Espressif Systems ESP32 Service Manual

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ESP32 Technical Reference Manual

Espressif Systems

August 31, 2016

About This Manual

ESP32 Technical Reference Manual targets application developers. The manual provides detailed and

complete information on how to use the ESP32 memory and peripherals.

Release Notes

Date Version Release notes

2016.08 V1.0 Initial release.

Disclaimer and Copyright Notice

Information in this document, including URL references, is subject to change without notice. THIS DOCUMENT

IS PROVIDED AS IS WITH NO WARRANTIES WHATSOEVER, INCLUDING ANY WARRANTY OF

MERCHANTABILITY, NON-INFRINGEMENT, FITNESS FOR ANY PARTICULAR PURPOSE, OR ANY WARRANTY

OTHERWISE ARISING OUT OF ANY PROPOSAL, SPECIFICATION OR SAMPLE.

All liability, including liability for infringement of any proprietary rights, relating to use of information in this

document is disclaimed. No licenses express or implied, by estoppel or otherwise, to any intellectual property

rights are granted herein. The Wi-Fi Alliance Member logo is a trademark of the Wi-Fi Alliance. The Bluetooth

logo is a registered trademark of Bluetooth SIG.

All trade names, trademarks and registered trademarks mentioned in this document are property of their

respective owners, and are hereby acknowledged.

Contents

1 System and Memory 8

1.1 Introduction 8

1.2 Features 8

1.3 Functional Description 10

1.3.1 Address Mapping 10

1.3.2 Embedded Memory 10

1.3.2.1 Internal ROM 0 11

1.3.2.2 Internal ROM 1 11

1.3.2.3 Internal SRAM 0 12

1.3.2.4 Internal SRAM 1 12

1.3.2.5 Internal SRAM 2 13

1.3.2.6 DMA 13

1.3.2.7 RTC FAST Memory 13

1.3.2.8 RTC SLOW Memory 13

1.3.3 External Memory 13

1.3.4 Peripherals 14

1.3.4.1 Asymmetric PID Controller Peripheral 15

1.3.4.2 Non-Contiguous Peripheral Memory Ranges 15

1.3.4.3 Memory Speed 16

2 Interrupt Matrix 17

2.1 Introduction 17

2.2 Features 17

2.3 Functional Description 17

2.3.1 Peripheral Interrupt Source 17

2.3.2 CPU Interrupt 20

2.3.3 Allocate Peripheral Interrupt Sources to Peripheral Interrupt on CPU 20

2.3.4 CPU NMI Interrupt Mask 21

2.3.5 Query Current Interrupt Status of Peripheral Interrupt Source 21

3 Reset and Clock 22

3.1 System Reset 22

3.1.1 Introduction 22

3.1.2 Reset Source 22

3.2 System Clock 23

3.2.1 Introduction 23

3.2.2 Clock Source 24

3.2.3 CPU Clock 24

3.2.4 Peripheral Clock 25

3.2.4.1 APB_CLK Source 25

3.2.4.2 REF_TICK Source 26

3.2.4.3 LEDC_SCLK Source 26

3.2.4.4 APLL_SCLK Source 26

3.2.4.5 PLL_D2_CLK Source 26

3.2.4.6 Clock Source Considerations 27

3.2.5 Wi-Fi BT Clock 27

3.2.6 RTC Clock 27

4 IO_MUX and GPIO Matrix 28

4.1 Introduction 28

4.2 Peripheral Input via GPIO Matrix 29

4.2.1 Summary 29

4.2.2 Functional Description 29

4.2.3 Simple GPIO Input 30

4.3 Peripheral Output via GPIO Matrix 30

4.3.1 Summary 30

4.3.2 Functional Description 30

4.3.3 Simple GPIO Output 31

4.4 Direct I/O via IO_MUX 31

4.4.1 Summary 31

4.4.2 Functional Description 32

4.5 RTC IO_MUX for Low Power and Analog I/O 32

4.5.1 Summary 32

4.5.2 Functional Description 32

4.6 Light-sleep Mode Pin Functions 32

4.7 Pad Hold Feature 33

4.8 I/O Pad Power Supply 33

4.8.1 VDD_SDIO Power Domain 33

4.9 Peripheral Signal List 34

4.10 IO_MUX Pad List 38

4.11 RTC_MUX Pin List 39

4.12 Register Summary 40

4.13 Registers 45

5 LED_PWM 66

5.1 Introduction 66

5.2 Functional Description 66

5.2.1 Architecture 66

5.2.2 Timers 67

5.2.3 Channels 67

5.2.4 Interrupts 68

5.3 Register Summary 68

5.4 Registers 71

6 Remote Controller Peripheral 81

6.1 Introduction 81

6.2 Functional Description 81

6.2.1 RMT Architecture 81

6.2.2 RMT RAM 82

6.2.3 Clock 82

6.2.4 Transmitter 82

6.2.5 Receiver 83

6.2.6 Interrupts 83

6.3 Register Summary 84

6.4 Registers 85

7 PULSE_CNT 90

7.1 Introduction 90

7.2 Functional Description 90

7.2.1 Architecture 90

7.2.2 Counter Channel Inputs 90

7.2.3 Watchpoints 91

7.2.4 Examples 92

7.2.5 Interrupts 92

7.3 Register Summary 92

7.4 Registers 94

8 64-bit Timers 98

8.1 Introduction 98

8.2 Functional Description 98

8.2.1 16-bit Prescaler 98

8.2.2 64-bit Time-base Counter 98

8.2.3 Alarm Generation 99

8.2.4 MWDT 99

8.2.5 Interrupts 99

8.3 Register summary 99

8.4 Registers 101

9 Watchdog Timers 108

9.1 Introduction 108

9.2 Features 108

9.3 Functional Description 108

9.3.1 Clock 108

9.3.1.1 Operating Procedure 109

9.3.1.2 Write Protection 109

9.3.1.3 Flash Boot Protection 109

9.3.1.4 Registers 110

10 AES Accelerator 111

10.1 Introduction 111

10.2 Features 111

10.3 Functional Description 111

10.3.1 AES Algorithm Operations 111

10.3.2 Key, Plaintext and Ciphertext 111

10.3.3 Endianness 112

10.3.4 Encryption and Decryption Operations 114

10.3.5 Speed 114

10.4 Register summary 114

10.5 Registers 116

11 SHA Accelerator 118

11.1 Introduction 118

11.2 Features 118

11.3 Functional Description 118

11.3.1 Padding and Parsing the Message 118

11.3.2 Message Digest 118

11.3.3 Hash Operation 119

11.3.4 Speed 119

11.4 Register Summary 119

11.5 Registers 121

List of Tables

1 Address Mapping 10

2 Embedded Memory Address Mapping 11

3 Module with DMA 13

4 External Memory Address Mapping 14

5 Peripheral Address Mapping 14

6 PRO_CPU, APP_CPU interrupt configuration 18

7 CPU Interrupts 20

8 PRO_CPU and APP_CPU reset reason values 22

9 CPU_CLK Source 24

10 CPU_CLK Derivation 25

11 Peripheral Clock Usage 25

12 APB_CLK Derivation 26

13 REF_TICK Derivation 26

14 LEDC_SCLK Derivation 26

15 IO_MUX Light-sleep Pin Function Registers 32

16 GPIO Matrix Peripheral Signals 34

17 IO_MUX Pad Summary 38

18 RTC_MUX Pin Summary 39

26 Operation Mode 111

27 AES Text Endianness 112

28 AES-128 Key Endianness 113

29 AES-192 Key Endianness 113

30 AES-256 Key Endianness 113

List of Figures

1 System Structure 9

2 System Address Mapping 9

3 Interrupt Matrix Structure 17

4 System Reset 22

5 System Clock 23

6 IO_MUX, RTC IO_MUX and GPIO Matrix Overview 28

7 Peripheral Input via IO_MUX, GPIO Matrix 29

8 Output via GPIO Matrix 31

9 ESP32 I/O Pad Power Sources 33

10 LED_PWM Architecture 66

11 LED_PWM High-speed Channel Diagram 66

12 LED PWM Output Signal Diagram 67

13 Output Signal Diagram of Gradient Duty Cycle 68

14 RMT Architecture 81

15 Data Structure 82

16 PULSE_CNT Architecture 90

17 PULSE_CNT Upcounting Diagram 92

18 PULSE_CNT Downcounting Diagram 92

1 SYSTEM AND MEMORY

1. System and Memory

1.1 Introduction

The ESP32 is a dual-core system with two Harvard Architecture Xtensa LX6 CPUs. All embedded memory,

external memory and peripherals are located on the data bus and/or the instruction bus of these CPUs.

With some minor exceptions (see below), the address mapping of two CPUs is symmetric, meaning they use the

same addresses to access the same memory. Multiple peripherals in the system can access embedded memory

via DMA.

The two CPUs are named “PRO_CPU” and “APP_CPU” (for “protocol” and “application”), however for most

purposes the two CPUs are interchangeable.

1.2 Features

• Address Space

– Symmetric address mapping

– 4 GB (32-bit) address space for both data bus and instruction bus

– 1296 KB embedded memory address space

– 19704 KB external memory address space

– 512 KB peripheral address space

– Some embedded and external memory regions can be accessed by either data bus or instruction bus

– 328 KB DMA address space

• Embedded Memory

– 448 KB Internal ROM

– 520 KB Internal SRAM

– 8 KB RTC FAST Memory

– 8 KB RTC SLOW Memory

• External Memory

Off-chip SPI memory can be mapped into the available address space as external memory. Parts of the

embedded memory can be used as transparent cache for this external memory.

– Supports up to 16 MB off-Chip SPI Flash.

– Supports up to 8 MB off-Chip SPI SRAM.

• Peripherals

– 41 peripherals

• DMA

– 13 modules are capable of DMA operation

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1.2 Features 1 SYSTEM AND MEMORY

Figure 1 block diagram illustrates the system structure, the block diagram in Figure 2 illustrates the address map

structure.

Figure 1: System Structure

Figure 2: System Address Mapping

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1.3 Functional Description 1 SYSTEM AND MEMORY

1.3 Functional Description

1.3.1 Address Mapping

Each of the two Harvard Architecture Xtensa LX6 CPUs has 4 GB (32-bit) address space. Address spaces are

symmetric between the two CPUs.

Addresses below 0x4000_0000 are serviced using the data bus. Addresses in the range 0x4000_0000 ~

0x4FFF_FFFF are serviced using the instruction bus. Finally, addresses over and including 0x5000_0000 are

shared by the data and instruction bus.

The data bus and instruction bus are both little-endian: for example, byte addresses 0x0, 0x1, 0x2, 0x3 access

the least significant, second least significant, second most significant, and most significant bytes of the 32-bit

word stored at address 0x0, respectively. The CPU can access data bus addresses via aligned or non-aligned

byte, half-word and word read and write operations. The CPU can read and write data through the instruction

bus, but only in a word aligned manner; non-word-aligned access will cause a CPU exception.

Each CPU can directly access embedded memory through both the data bus and the instruction bus, external

memory which is mapped into the address space (via transparent caching & MMU) and peripherals. Table 1

illustrates address ranges that can be accessed by each CPU’s data bus and instruction bus.

Some embedded memories and some external memories can be accessed via the data bus or the instruction

bus. In these cases, the same memory is available to either of the CPUs at two address ranges.

Table 1: Address Mapping

Bus Type

Data 0x3F40_0000 0x3F7F_FFFF 4 MB External Memory

Data 0x3F80_0000 0x3FBF_FFFF 4 MB External Memory

Data 0x3FF0_0000 0x3FF7_FFFF 512 KB Peripheral

Data 0x3FF8_0000 0x3FFF_FFFF 512 KB Embedded Memory

Instruction 0x4000_0000 0x400C_1FFF 776 KB Embedded Memory

Instruction 0x400C_2000 0x40BF_FFFF 11512 KB External Memory

Data Instruction 0x5000_0000 0x5000_1FFF 8 KB Embedded Memory

Low Address High Address

0x0000_0000 0x3F3F_FFFF Reserved

0x3FC0_0000 0x3FEF_FFFF 3 MB Reserved

0x40C0_0000 0x4FFF_FFFF 244 MB Reserved

0x5000_2000 0xFFFF_FFFF Reserved

Boundary Address

Size Target

1.3.2 Embedded Memory

The Embedded Memory consists of four segments: internal ROM (448 KB), internal SRAM (520 KB), RTC FAST

memory (8 KB) and RTC SLOW memory (8 KB).

The 448 KB internal ROM is divided into two parts: Internal ROM 0 (384 KB) and Internal ROM 1 (64 KB).

The 520 KB internal SRAM is divided into three parts: Internal SRAM 0 (192 KB), Internal SRAM 1 (128 KB), and

Internal SRAM 2 (200 KB).

RTC FAST Memory and RTC SLOW Memory are both implemented as SRAM.

Table 2 lists all embedded memories and their address ranges on the data and instruction buses.

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1.3 Functional Description 1 SYSTEM AND MEMORY

Table 2: Embedded Memory Address Mapping

Bus Type

Data 0x3FF8_0000 0x3FF8_1FFF 8 KB RTC FAST Memory PRO_CPU Only

Data 0x3FF9_0000 0x3FF9_FFFF 64 KB Internal ROM 1 -

Data 0x3FFA_E000 0x3FFD_FFFF 200 KB Internal SRAM 2 DMA

Data 0x3FFE_0000 0x3FFF_FFFF 128 KB Internal SRAM 1 DMA

Bus Type

Instruction 0x4000_0000 0x4000_7FFF 32 KB Internal ROM 0 Remap

Instruction 0x4000_8000 0x4005_FFFF 352 KB Internal ROM 0 -

Instruction 0x4007_0000 0x4007_FFFF 64 KB Internal SRAM 0 Cache

Instruction 0x4008_0000 0x4009_FFFF 128 KB Internal SRAM 0 -

Instruction 0x400A_0000 0x400A_FFFF 64 KB Internal SRAM 1 -

Instruction 0x400B_0000 0x400B_7FFF 32 KB Internal SRAM 1 Remap

Instruction 0x400B_8000 0x400B_FFFF 32 KB Internal SRAM 1 -

Instruction 0x400C_0000 0x400C_1FFF 8 KB RTC FAST Memory PRO_CPU Only

Bus Type

Data Instruc-

tion

Low Address High Address

0x3FF8_2000 0x3FF8_FFFF 56 KB Reserved -

0x3FFA_0000 0x3FFA_DFFF 56 KB Reserved -

Low Address High Address

0x4006_0000 0x4006_FFFF 64 KB Reserved -

Low Address High Address

0x5000_0000 0x5000_1FFF 8 KB RTC SLOW Memory -

Boundary Address

Size Target Comment

1.3.2.1 Internal ROM 0

The capacity of Internal ROM 0 is 384 KB, It is accessible by both CPUs through the address range

0x4000_0000 ~ 0x4005_FFFF, which is on the instruction bus.

The address range of the first 32 KB of the ROM 0 (0x4000_0000 ~ 0x4000_7FFF) can be re-mapped to access

a part of Internal SRAM 1 that normally resides in the memory range 0x400B_0000 ~ 0x400B_7FFF instead.

While remapping, such 32 KB SRAM can not be accessed by address range 0x400B_0000 ~ 0x400B_7FFF any

more, but it can still be accessible through the data bus (0x3FFE_8000 ~ 0x3FFE_FFFF). This can be done on a

per-CPU basis: setting bit 0 of register DPORT_PRO_BOOT_REMAP_CTRL_REG or

DPORT_APP_BOOT_REMAP_CTRL_REG will remap SRAM for the PRO_CPU and APP_CPU,

respectively.

1.3.2.2 Internal ROM 1

The capacity of Internal ROM 1 is 64 KB. It can be read by either CPU at address range 0x3FF9_0000 ~

0x3FF9_FFFF of the data bus.

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1.3 Functional Description 1 SYSTEM AND MEMORY

1.3.2.3 Internal SRAM 0

The capacity of Internal SRAM 0 is 192 KB. Hardware can be configured to use the first 64KB to cache external

memory access. When not used as cache, the first 64KB can be read and written by either CPU at addresses

0x4007_0000 ~ 0x4007_7FFF of the instruction bus. The remaining 128 KB can always be read and written by

either CPU at addresses 0x4007_8000 ~ 0x4007_FFFF of instruction bus.

1.3.2.4 Internal SRAM 1

The capacity of Internal SRAM 1 is 128 KB. Either CPU can read and write this memory at addresses

0x3FFE_0000 ~ 0x3FFF_FFFF of the data bus, and also at addresses 0x400A_0000 ~ 0x400B_FFFF of the

instruction bus.

The address range accessed via the instruction bus is in reverse order (word-wise) compared to access via the

data bus. That is to say, address

0x3FFE_0000 and 0x400B_FFFC access the same word

0x3FFE_0004 and 0x400B_FFF8 access the same word

0x3FFE_0008 and 0x400B_FFF4 access the same word

……

0x3FFF_FFF4 and 0x400A_0008 access the same word

0x3FFF_FFF8 and 0x400A_0004 access the same word

0x3FFF_FFFC and 0x400A_0000 access the same word

The data bus and instruction bus of the CPU are still both little endian, so the byte order of individual words is not

reversed between address spaces. For example, address

0x3FFE_0000 accesses the least significant byte in the word accessed by 0x400B_FFFC.

0x3FFE_0001 accesses the second least significant byte in the word accessed by 0x400B_FFFC.

0x3FFE_0002 accesses the second most significant byte in the word accessed by 0x400B_FFFC.

0x3FFE_0003 accesses the most significant byte in the word accessed by 0x400B_FFFC.

0x3FFE_0004 accesses the least significant byte in the word accessed by 0x400B_FFF8.

0x3FFE_0005 accesses the second least significant byte in the word accessed by 0x400B_FFF8.

0x3FFE_0006 accesses the second most significant byte in the word accessed by 0x400B_FFF8.

0x3FFE_0007 accesses the most significant byte in the word accessed by 0x400B_FFF8.

……

0x3FFF_FFF8 accesses the least significant byte in the word accessed by 0x400A_0004.

0x3FFF_FFF9 accesses the second least significant byte in the word accessed by 0x400A_0004.

0x3FFF_FFFA accesses the second most significant byte in the word accessed by 0x400A_0004.

0x3FFF_FFFB accesses the most significant byte in the word accessed by 0x400A_0004.

0x3FFF_FFFC accesses the least significant byte in the word accessed by 0x400A_0000.

0x3FFF_FFFD accesses the second most significant byte in the word accessed by 0x400A_0000.

0x3FFF_FFFE accesses the second most significant byte in the word accessed by 0x400A_0000.

0x3FFF_FFFF accesses the most significant byte in the word accessed by 0x400A_0000.

Part of this memory can be remapped to the ROM 0 address space. See Internal Rom 0 for more

information.

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1.3 Functional Description 1 SYSTEM AND MEMORY

1.3.2.5 Internal SRAM 2

The capacity of Internal SRAM 2 is 200 KB. It can be read and written by either CPU at addresses 0x3FFA_E000

~ 0x3FFD_FFFF on the data bus.

1.3.2.6 DMA

DMA uses the same addressing as the CPU data bus to read and write Internal SRAM 1 and Internal SRAM 2.

This means DMA uses address range 0x3FFE_0000 ~ 0x3FFF_FFFF to read and write Internal SRAM 1 and

address range 0x3FFA_E000 ~ 0x3FFD_FFFF to read and write Internal SRAM 2.

In the ESP32, 13 peripherals are equipped with DMA. Table 3 lists these peripherals.

Table 3: Module with DMA

UART0 UART1 UART2

SPI1 SPI2 SPI3

I2S0 I2S1

SDIO Slave SDMMC

EMAC

BT WIFI

1.3.2.7 RTC FAST Memory

RTC FAST Memory is 8 KB of SRAM. It can be read and written by PRO_CPU only at address range

0x3FF8_0000 ~ 0x3FF8_1FFF on the data bus or address range 0x400C_0000 ~ 0x400C_1FFF on the

instruction bus. Unlike most other memory regions, RTC FAST memory cannot be accessed by the

APP_CPU.

The two address ranges of PRO_CPU access RTC FAST Memory in the same order, so for example, address

0x3FF8_0000 and 0x400C_0000 access the same word. On the APP_CPU, these address ranges do not

provide access to RTC FAST Memory or any other memory location.

1.3.2.8 RTC SLOW Memory

RTC SLOW Memory is 8 KB of SRAM which can be read from and written by either CPU at address range

0x5000_0000 ~ 0x5000_1FFF. This address range is shared by both the data bus and the instruction bus.

1.3.3 External Memory

The ESP32 can access external SPI flash and SPI SRAM as external memory. Table 4 provides a list of external

memories that can be accessed by either CPU at a range of addresses on the data and instruction buses. When

a CPU accesses external memory through the Cache and MMU, the cache will map the CPU’s address to an

external physical memory address (in the external memory’s address space), according to the MMU settings. Due

to this address mapping, the ESP32 can address up to 16 MB External Flash and 8 MB External SRAM.

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1.3 Functional Description 1 SYSTEM AND MEMORY

Table 4: External Memory Address Mapping

Bus Type

Data 0x3F40_0000 0x3F7F_FFFF 4 MB External Flash Read

Data 0x3F80_0000 0x3FBF_FFFF 4 MB External SRAM Read and Write

Bus Type

Instruction 0x400C_2000 0x40BF_FFFF 11512 KB External Flash Read

Low Address High Address

Boundary Address

Size Target Comment

1.3.4 Peripherals

The ESP32 has 41 peripherals. Table 5 specifically describes the peripherals their respective address ranges.

Almost all peripheral modules can be accessed by either CPU at the same address, the only exception being the

PID Controller.

Table 5: Peripheral Address Mapping

Bus Type

Data 0x3FF0_0000 0x3FF0_0FFF 4 KB DPort Register

Data 0x3FF0_1000 0x3FF0_1FFF 4 KB AES Accelerator

Data 0x3FF0_2000 0x3FF0_2FFF 4 KB RSA Accelerator

Data 0x3FF0_3000 0x3FF0_3FFF 4 KB SHA Accelerator

Data 0x3FF0_4000 0x3FF0_4FFF 4 KB Secure Boot

Data 0x3FF1_0000 0x3FF1_3FFF 16 KB Cache MMU Table

Data 0x3FF1_F000 0x3FF1_FFFF 4 KB PID Controller Per-CPU peripheral

Data 0x3FF4_0000 0x3FF4_0FFF 4 KB UART0

Data 0x3FF4_2000 0x3FF4_2FFF 4 KB SPI1

Data 0x3FF4_3000 0x3FF4_3FFF 4 KB SPI0

Data 0x3FF4_4000 0x3FF4_4FFF 4 KB GPIO

Data 0x3FF4_8000 0x3FF4_8FFF 4 KB RTC

Data 0x3FF4_9000 0x3FF4_9FFF 4 KB IO MUX

Data 0x3FF4_B000 0x3FF4_BFFF 4 KB SDIO Slave One of three parts

Data 0x3FF4_C000 0x3FF4_CFFF 4 KB UDMA1

Data 0x3FF4_F000 0x3FF4_FFFF 4 KB I2S0

Data 0x3FF5_0000 0x3FF5_0FFF 4 KB UART1

Data 0x3FF5_3000 0x3FF5_3FFF 4 KB I2C0

Data 0x3FF5_4000 0x3FF5_4FFF 4 KB UDMA0

Low Address High Address

0x3FF0_5000 0x3FF0_FFFF 44 KB Reserved

0x3FF1_4000 0x3FF1_EFFF 44 KB Reserved

0x3FF2_0000 0x3FF3_FFFF 128 KB Reserved

0x3FF4_1000 0x3FF4_1FFF 4 KB Reserved

0x3FF4_5000 0x3FF4_7FFF 12 KB Reserved

0x3FF4_A000 0x3FF4_AFFF 4 KB Reserved

0x3FF4_D000 0x3FF4_EFFF 8 KB Reserved

0x3FF5_1000 0x3FF5_2FFF 8 KB Reserved

Boundary Address

Size Target Comment

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1.3 Functional Description 1 SYSTEM AND MEMORY

Bus Type

Data 0x3FF5_5000 0x3FF5_5FFF 4 KB SDIO Slave One of three parts

Data 0x3FF5_6000 0x3FF5_6FFF 4 KB RMT

Data 0x3FF5_7000 0x3FF5_7FFF 4 KB PCNT

Data 0x3FF5_8000 0x3FF5_8FFF 4 KB SDIO Slave One of three parts

Data 0x3FF5_9000 0x3FF5_9FFF 4 KB LED PWM

Data 0x3FF5_A000 0x3FF5_AFFF 4 KB Efuse Controller

Data 0x3FF5_B000 0x3FF5_BFFF 4 KB Flash Encryption

Data 0x3FF5_E000 0x3FF5_EFFF 4 KB PWM0

Data 0x3FF5_F000 0x3FF5_FFFF 4 KB TIMG0

Data 0x3FF6_0000 0x3FF6_0FFF 4 KB TIMG1

Data 0x3FF6_4000 0x3FF6_4FFF 4 KB SPI2

Data 0x3FF6_5000 0x3FF6_5FFF 4 KB SPI3

Data 0x3FF6_6000 0x3FF6_6FFF 4 KB SYSCON

Data 0x3FF6_7000 0x3FF6_7FFF 4 KB I2C1

Data 0x3FF6_8000 0x3FF6_8FFF 4 KB SDMMC

Data 0x3FF6_9000 0x3FF6_AFFF 8 KB EMAC

Data 0x3FF6_C000 0x3FF6_CFFF 4 KB PWM1

Data 0x3FF6_D000 0x3FF6_DFFF 4 KB I2S1

Data 0x3FF6_E000 0x3FF6_EFFF 4 KB UART2

Data 0x3FF6_F000 0x3FF6_FFFF 4 KB PWM2

Data 0x3FF7_0000 0x3FF7_0FFF 4 KB PWM3

Data 0x3FF7_5000 0x3FF7_5FFF 4 KB RNG

Low Address High Address

0x3FF5_C000 0x3FF5_DFFF 8 KB Reserved

0x3FF6_1000 0x3FF6_3FFF 12 KB Reserved

0x3FF6_B000 0x3FF6_BFFF 4 KB Reserved

0x3FF7_1000 0x3FF7_4FFF 16 KB Reserved

0x3FF7_6000 0x3FF7_FFFF 40 KB Reserved

Boundary Address

Size Target Comment

1.3.4.1 Asymmetric PID Controller Peripheral

There are two PID Controllers in the system. They serve the PRO_CPU and the APP_CPU, respectively. The

PRO_CPU and the APP_CPU can only access their own PID Controller and not their counterpart’s PID

Controller. Each CPU uses the same memory range 0x3FF1_F000 ~ 3FF1_FFFF to access its own PID

Controller.

1.3.4.2 Non-Contiguous Peripheral Memory Ranges

The SDIO Slave peripheral consists of three parts and the two CPUs use non-contiguous addresses to access

these. The three parts are accessed at the address ranges 0x3FF4_B000 ~ 3FF4_BFFF, 0x3FF5_5000 ~

3FF5_5FFF and 0x3FF5_8000 ~ 3FF5_8FFF of each CPU’s data bus. Similar to other peripherals, access to this

peripheral is identical for both CPUs.

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1.3 Functional Description 1 SYSTEM AND MEMORY

1.3.4.3 Memory Speed

The ROM as well as the SRAM are both clocked from CPU_CLK and can be accessed by the CPU in a single

cycle. The RTC FAST memory is clocked from the APB_CLOCK and the RTC SLOW memory from the

FAST_CLOCK, so access to these memories may be slower. DMA uses the APB_CLK to access memory.

Internally, the SRAM is organized in 32K-sized banks. Each CPU and DMA channel can access the SRAM at full

speed and simultaneously, provided they access address different memory banks.

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2 INTERRUPT MATRIX

2. Interrupt Matrix

2.1 Introduction

The Interrupt Matrix embedded in the ESP32 independently allocates peripheral interrupt sources to the two

CPUs’ peripheral interrupts. This configuration is highly flexible in order to meet many different needs.

2.2 Features

• Accepts 71 peripheral interrupt sources as input.

• Generates 26 peripheral interrupt sources per CPU as output (52 total).

• CPU NMI Interrupt Mask.

• Queries current interrupt status of peripheral interrupt sources.

The structure of the Interrupt Matrix is shown in Figure 3.

Figure 3: Interrupt Matrix Structure

2.3 Functional Description

2.3.1 Peripheral Interrupt Source

ESP32 has 71 peripheral interrupt sources in total. All peripheral interrupt sources are listed in table 6. 67 of 71

ESP32 peripheral interrupt sources can be allocated to either CPU.

The four remaining peripheral interrupt sources are CPU-specific, two per CPU. GPIO_INTERRUPT_PRO and

GPIO_INTERRUPT_PRO_NMI can only be allocated to PRO_CPU. GPIO_INTERRUPT_APP and

GPIO_INTERRUPT_APP_NMI can only be allocated to APP_CPU. As a result, PRO_CPU and APP_CPU each

have 69 peripheral interrupt sources.

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Table 6: PRO_CPU, APP_CPU interrupt configuration

2.3 Functional Description 2 INTERRUPT MATRIX

PRO_CPU APP_CPU

Peripheral Interrupt

Configuration Register

PRO_MAC_INTR_MAP_REG 0

PRO_MAC_NMI_MAP_REG 1 1 MAC_NMI 1 1 APP_MAC_NMI_MAP_REG

PRO_BB_INT_MAP_REG 2 2 BB_INT 2 2 APP_BB_INT_MAP_REG

PRO_BT_MAC_INT_MAP_REG 3 3 BT_MAC_INT 3 3 APP_BT_MAC_INT_MAP_REG

PRO_BT_BB_INT_MAP_REG 4 4 BT_BB_INT 4 4 APP_BT_BB_INT_MAP_REG

PRO_BT_BB_NMI_MAP_REG 5 5 BT_BB_NMI 5 5 APP_BT_BB_NMI_MAP_REG

PRO_RWBT_IRQ_MAP_REG 6 6 RWBT_IRQ 6 6 APP_RWBT_IRQ_MAP_REG

PRO_BT_BB_NMI_MAP_REG 5 5 BT_BB_NMI 5 5 APP_BT_BB_NMI_MAP_REG

PRO_RWBT_IRQ_MAP_REG 6 6 RWBT_IRQ 6 6 APP_RWBT_IRQ_MAP_REG

PRO_RWBLE_IRQ_MAP_REG 7 7 RWBLE_IRQ 7 7 APP_RWBLE_IRQ_MAP_REG

PRO_RWBT_NMI_MAP_REG 8 8 RWBT_NMI 8 8 APP_RWBT_NMI_MAP_REG

PRO_RWBLE_NMI_MAP_REG 9 9 RWBLE_NMI 9 9 APP_RWBLE_NMI_MAP_REG

PRO_SLC0_INTR_MAP_REG 10 10 SLC0_INTR 10 10 APP_SLC0_INTR_MAP_REG

PRO_SLC1_INTR_MAP_REG 11 11 SLC1_INTR 11 11 APP_SLC1_INTR_MAP_REG

PRO_UHCI0_INTR_MAP_REG 12 12 UHCI0_INTR 12 12 APP_UHCI0_INTR_MAP_REG

PRO_UHCI1_INTR_MAP_REG 13 13 UHCI1_INTR 13 13 APP_UHCI1_INTR_MAP_REG

PRO_TG_T0_LEVEL_INT_MAP_REG 14 14 TG_T0_LEVEL_INT 14 14 APP_TG_T0_LEVEL_INT_MAP_REG

PRO_TG_T1_LEVEL_INT_MAP_REG 15 15 TG_T1_LEVEL_INT 15 15 APP_TG_T1_LEVEL_INT_MAP_REG

PRO_TG_WDT_LEVEL_INT_MAP_REG 16 16 TG_WDT_LEVEL_INT 16 16 APP_TG_WDT_LEVEL_INT_MAP_REG

PRO_TG_LACT_LEVEL_INT_MAP_REG 17 17 TG_LACT_LEVEL_INT 17 17 APP_TG_LACT_LEVEL_INT_MAP_REG

PRO_TG1_T0_LEVEL_INT_MAP_REG 18 18 TG1_T0_LEVEL_INT 18 18 APP_TG1_T0_LEVEL_INT_MAP_REG

PRO_TG1_T1_LEVEL_INT_MAP_REG 19 19 TG1_T1_LEVEL_INT 19 19 APP_TG1_T1_LEVEL_INT_MAP_REG

PRO_TG1_WDT_LEVEL_INT_MAP_REG 20 20 TG1_WDT_LEVEL_INT 20 20 APP_TG1_WDT_LEVEL_INT_MAP_REG

PRO_TG1_LACT_LEVEL_INT_MAP_REG 21 21 TG1_LACT_LEVEL_INT 21 21 APP_TG1_LACT_LEVEL_INT_MAP_REG

PRO_GPIO_INTERRUPT_PRO_MAP_REG

PRO_GPIO_INTERRUPT_PRO_NMI_MAP_REG

PRO_CPU_INTR_FROM_CPU_0_MAP_REG 24 24 CPU_INTR_FROM_CPU_0 24 24 APP_CPU_INTR_FROM_CPU_0_MAP_REG

PRO_CPU_INTR_FROM_CPU_1_MAP_REG 25 25 CPU_INTR_FROM_CPU_1 25 25 APP_CPU_INTR_FROM_CPU_1_MAP_REG

PRO_CPU_INTR_FROM_CPU_2_MAP_REG 26 26 CPU_INTR_FROM_CPU_2 26 26 APP_CPU_INTR_FROM_CPU_2_MAP_REG

PRO_CPU_INTR_FROM_CPU_3_MAP_REG 27 27 CPU_INTR_FROM_CPU_3 27 27 APP_CPU_INTR_FROM_CPU_3_MAP_REG

PRO_SPI_INTR_0_MAP_REG 28 28 SPI_INTR_0 28 28 APP_SPI_INTR_0_MAP_REG

PRO_SPI_INTR_1_MAP_REG 29 29 SPI_INTR_1 29 29 APP_SPI_INTR_1_MAP_REG

PRO_SPI_INTR_2_MAP_REG 30 30 SPI_INTR_2 30 30 APP_SPI_INTR_2_MAP_REG

PRO_SPI_INTR_3_MAP_REG 31 31 SPI_INTR_3 31 31 APP_SPI_INTR_3_MAP_REG

PRO_I2S0_INT_MAP_REG 0

PRO_I2S1_INT_MAP_REG 1 33 I2S1_INT 33 1 APP_I2S1_INT_MAP_REG

PRO_UART_INTR_MAP_REG 2 34 UART_INTR 34 2 APP_UAR T_INTR_MAP_REG

PRO_UART1_INTR_MAP_REG 3 35 UART1_INTR 35 3 APP_UART1_INTR_MAP_REG

PRO_UART2_INTR_MAP_REG 4 36 UART2_INTR 36 4 APP_UART2_INTR_MAP_REG

PRO_SDIO_HOST_INTERRUPT_MAP_REG 5 37 SDIO_HOST_INTERRUPT 37 5 APP_SDIO_HOST_INTERRUPT_MAP_REG

PRO_EMAC_INT_MAP_REG 6 38 EMAC_INT 38 6 APP_EMAC_INT_MAP_REG

PRO_PWM0_INTR_MAP_REG 7 39 PWM0_INTR 39 7 APP_PWM0_INTR_MAP_REG

PRO_PWM1_INTR_MAP_REG 8 40 PWM1_INTR 40 8 APP_PWM1_INTR_MAP_REG

PRO_PWM2_INTR_MAP_REG 9 41 PWM2_INTR 41 9 APP_PWM2_INTR_MAP_REG

PRO_PWM3_INTR_MAP_REG 10 42 PWM3_INTR 42 10 APP_PWM3_INTR_MAP_REG

PRO_LEDC_INT_MAP_REG 11 43 LEDC_INT 43 11 APP_LEDC_INT_MAP_REG

PRO_EFUSE_INT_MAP_REG 12 44 EFUSE_INT 44 12 APP_EFUSE_INT_MAP_REG

PRO_CAN_INT_MAP_REG 13 45 CAN_INT 45 13 APP_CAN_INT_MAP_REG

PRO_RTC_CORE_INTR_MAP_REG 14 46 RTC_CORE_INTR 46 14 APP_R TC_CORE_INTR_MAP_REG

PRO_RMT_INTR_MAP_REG 15 47 RMT_INTR 47 15 APP_RMT_INTR_MAP_REG

PRO_PCNT_INTR_MAP_REG 16 48 PCNT_INTR 48 16 APP_PCNT_INTR_MAP_REG

PRO_I2C_EXT0_INTR_MAP_REG 17 49 I2C_EXT0_INTR 49 17 APP_I2C_EXT0_INTR_MAP_REG

PRO_I2C_EXT1_INTR_MAP_REG 18 50 I2C_EXT1_INTR 50 18 APP_I2C_EXT1_INTR_MAP_REG

PRO_RSA_INTR_MAP_REG 19 51 RSA_INTR 51 19 APP_RSA_INTR_MAP_REG

PRO_SPI1_DMA_INT_MAP_REG 20 52 SPI1_DMA_INT 52 20 APP_SPI1_DMA_INT_MAP_REG

Status Register Status Register

Bit Name

PRO_INTR_STATUS_REG_0

22 22

23 23

PRO_INTR_STATUS_REG_1

No. Name No.

0 MAC_INTR 0

GPIO_INTERRUPT_PRO GPIO_INTERRUPT_APP

GPIO_INTERRUPT_PRO_NMI GPIO_INTERRUPT_APP_NMI

32 I2S0_INT 32

Peripheral Interrupt Source

Name Bit

APP_INTR_STATUS_REG_0

22 22

23 23

APP_INTR_STATUS_REG_1

Peripheral Interrupt

Configuration Register

0 APP_MAC_INTR_MAP_REG

APP_GPIO_INTERRUPT_APP_MAP_REG

APP_GPIO_INTERRUPT_APP_NMI_MAP_REG

0 APP_I2S0_INT_MAP_REG

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PRO_CPU APP_CPU

Peripheral Interrupt

Configuration Register

PRO_SPI2_DMA_INT_MAP_REG 21

PRO_SPI3_DMA_INT_MAP_REG 22 54 SPI3_DMA_INT 54 22 APP_SPI3_DMA_INT_MAP_REG

PRO_WDG_INT_MAP_REG 23 55 WDG_INT 55 23 APP_WDG_INT_MAP_REG

PRO_TIMER_INT1_MAP_REG 24 56 TIMER_INT1 56 24 APP_TIMER_INT1_MAP_REG

PRO_TIMER_INT2_MAP_REG 25 57 TIMER_INT2 57 25 APP_TIMER_INT2_MAP_REG

PRO_TG_T0_EDGE_INT_MAP_REG 26 58 TG_T0_EDGE_INT 58 26 APP_TG_T0_EDGE_INT_MAP_REG

PRO_TG_T1_EDGE_INT_MAP_REG 27 59 TG_T1_EDGE_INT 59 27 APP_TG_T1_EDGE_INT_MAP_REG

PRO_TG_WDT_EDGE_INT_MAP_REG 28 60 TG_WDT_EDGE_INT 60 28 APP_TG_WDT_EDGE_INT_MAP_REG

PRO_TG_LACT_EDGE_INT_MAP_REG 29 61 TG_LACT_EDGE_INT 61 29 APP_TG_LACT_EDGE_INT_MAP_REG

PRO_TG1_T0_EDGE_INT_MAP_REG 30 62 TG1_T0_EDGE_INT 62 30 APP_TG1_T0_EDGE_INT_MAP_REG

PRO_TG1_T1_EDGE_INT_MAP_REG 31 63 TG1_T1_EDGE_INT 63 31 APP_TG1_T1_EDGE_INT_MAP_REG

PRO_TG1_WDT_EDGE_INT_MAP_REG 0

PRO_TG1_LACT_EDGE_INT_MAP_REG 1 65 TG1_LACT_EDGE_INT 65 1 APP_TG1_LACT_EDGE_INT_MAP_REG

PRO_MMU_IA_INT_MAP_REG 2 66 MMU_IA_INT 66 2 APP_MMU_IA_INT_MAP_REG

PRO_MPU_IA_INT_MAP_REG 3 67 MPU_IA_INT 67 3 APP_MPU_IA_INT_MAP_REG

PRO_CACHE_IA_INT_MAP_REG 4 68 CACHE_IA_INT 68 4 APP_CACHE_IA_INT_MAP_REG

Status Register Status Register

Bit Name

PRO_INTR_STATUS_REG_1

PRO_INTR_STATUS_REG_2

No. Name No.

53 SPI2_DMA_INT 53

64 TG1_WDT_EDGE_INT 64

Peripheral Interrupt Source

Name Bit

APP_INTR_STATUS_REG_1

APP_INTR_STATUS_REG_2

Peripheral Interrupt

Configuration Register

21 APP_SPI2_DMA_INT_MAP_REG

0 APP_TG1_WDT_EDGE_INT_MAP_REG

2.3 Functional Description 2 INTERRUPT MATRIX

2.3.2 CPU Interrupt

Both of the two CPUs (PRO and APP) have 32 interrupts each, of which 26 are peripheral interrupts. All

interrupts in a CPU are listed in Table 7.

Table 7: CPU Interrupts

No. Category Type Priority Level

0 Peripheral Level-Triggered 1

1 Peripheral Level-Triggered 1

2 Peripheral Level-Triggered 1

3 Peripheral Level-Triggered 1

4 Peripheral Level-Triggered 1

5 Peripheral Level-Triggered 1

6 Internal Timer.0 1

7 Internal Software 1

8 Peripheral Level-Triggered 1

9 Peripheral Level-Triggered 1

10 Peripheral Edge-Triggered 1

11 Internal Profiling 3

12 Peripheral Level-Triggered 1

13 Peripheral Level-Triggered 1

14 Peripheral NMI NMI

15 Internal Timer.1 3

16 Internal Timer.2 5

17 Peripheral Level-Triggered 1

18 Peripheral Level-Triggered 1

19 Peripheral Level-Triggered 2

20 Peripheral Level-Triggered 2

21 Peripheral Level-Triggered 2

22 Peripheral Edge-Triggered 3

23 Peripheral Level-Triggered 3

24 Peripheral Level-Triggered 4

25 Peripheral Level-Triggered 4

26 Peripheral Level-Triggered 5

27 Peripheral Level-Triggered 3

28 Peripheral Edge-Triggered 4

29 Internal Software 3

30 Peripheral Edge-Triggered 4

31 Peripheral Level-Triggered 5

2.3.3 Allocate Peripheral Interrupt Sources to Peripheral Interrupt on CPU

In this section:

• Source_X stands for any particular peripheral interrupt source.

• PRO_X_MAP_REG (or APP_X_MAP_REG) stands for any particular peripheral interrupt configuration

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2.3 Functional Description 2 INTERRUPT MATRIX

peripheral interrupt source Source_X. Referring to Table 6, the registers listed under “PRO_CPU

(APP_CPU) - Peripheral Interrupt Configuration Register” correspond to the peripheral interrupt sources

listed in “Peripheral Interrupt Source - Name”.

• Interrupt_P stands for CPU peripheral interrupt, numbered as Num_P. Num_P can take the ranges 0 ~ 5, 8

~ 10, 12 ~ 14, 17 ~ 28, 30 ~ 31.

• Interrupt_I stands for CPU internal interrupt numbered as Num_I. Num_I can take values 6, 7, 11, 15, 16,

29.

Using this terminology, the possible operations of the Interrupt Matrix controller can be described as

follows:

• Allocate peripheral interrupt source Source_X to CPU (PRO_CPU or APP_CPU)

Set PRO_X_MAP_REG�or APP_X_MAP_REG�to Num_P. Num_P can be any CPU peripheral interrupt

number. CPU interrupts can be shared between multiple peripherals (see below).

• Disable peripheral interrupt source Source_X for CPU (PRO_CPU or APP_CPU)

Set PRO_X_MAP_REG�or APP_X _MAP_REG�for peripheral interrupt source to any Num_I. The specific

choice of internal interrupt number does not change behaviour, as none of the interrupt numbered as

Num_I are connected to either CPU.

• Allocate multiple peripheral sources Source_Xn ORed to PRO_CPU (APP_CPU) peripheral interrupt

Set multiple PRO_Xn_MAP_REG (APP_Xn_MAP_REG) to the same Num_P. Any of these peripheral

interrupts will trigger CPU Interrupt_P.

2.3.4 CPU NMI Interrupt Mask

The Interrupt Matrix temporarily masks all peripheral interrupt sources allocated to PRO_CPU’s ( or APP_CPU’s )

NMI interrupt if it receives the signal PRO_CPU NMI Interrupt Mask ( or APP_CPU NMI Interrupt Mask ) from the

peripheral PID Controller respectively.

2.3.5 Query Current Interrupt Status of Peripheral Interrupt Source

The current interrupt status of a peripheral interrupt source can be read via the bit value in

PRO_INTR_STATUS_REG_n (APP_INTR_STATUS_REG_n) as shown in the mapping in Table 6.

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3 RESET AND CLOCK

3. Reset and Clock

3.1 System Reset

3.1.1 Introduction

The ESP32 has three reset levels: CPU reset, Core reset, and System reset. None of these reset levels clear the

RAM. Figure 4 shows the subsystems included in each reset level.

Figure 4: System Reset

• CPU reset: Only resets the registers of one or both the CPU cores.

• Core reset: Resets all the digital registers, including CPU cores, external GPIO and digital GPIO. The RTC is

not reset.

• System reset: Resets all the registers on the chip, including those of the RTC.

3.1.2 Reset Source

While most of the time the APP_CPU and PRO_CPU will be reset simultaneously, some reset sources are able to

reset only one of the two cores. The reset reason for each core can be looked up individually: the PRO_CPU

reset reason will be stored in RTC_CNTL_RESET_CAUSE_PROCPU, the reset reason for the APP_CPU in

APP_CNTL_RESET_CAUSE_PROCPU. Table 8 shows the possible reset reason values that can be read from

these registers.

Table 8: PRO_CPU and APP_CPU reset reason values

PRO APP Source Reset Type Note

0x01 0x01 Chip Power On Reset System Reset -

0x10 0x10 RWDT System Reset System Reset Refer to WDT Chapter.

0x0F 0x0F Brown Out Reset System Reset Refer to Power Management Chapter.

0x03 0x03 Software System Reset Core Reset Configure RTC_CNTL_SW_SYS_RST register.

0x05 0x05 Deep Sleep Rest Core Reset Refer to Power Management Chapter.

0x07 0x07 MWDT0 Global Reset Core Reset Refer to WDT Chapter.

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3.2 System Clock 3 RESET AND CLOCK

PRO APP APP Source Reset Type Note

0x08 0x08 MWDT1 Global Reset Core Reset Refer to WDT Chapter.

0x09 0x09 RWDT Core Reset Core Reset Refer to WDT Chapter.

0x0B - MWDT0 CPU Reset CPU Reset Refer to WDT Chapter.

0x0C - Software CPU Reset CPU Reset Configure RTC_CNTL_SW_APPCPU_RST register.

- 0x0B MWDT1 CPU Reset CPU Reset Refer to WDT Chapter.

- 0x0C Software CPU Reset CPU Reset Configure RTC_CNTL_SW_APPCPU_RST register.

0x0D 0x0D RWDT CPU Reset CPU Reset Refer to WDT Chapter.

Indicates that the PRO CPU has indepen-

- 0xE PRO CPU Reset CPU Reset

dently reset the APP CPU by configuring the

DPORT_APPCPU_RESETTING register.

3.2 System Clock

3.2.1 Introduction

The ESP32 integrates multiple clock sources for the CPU cores, the peripherals and the RTC. These clocks can

be configured to meet different requirements. Figure 5 shows the system clock structure.

Figure 5: System Clock

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3.2 System Clock 3 RESET AND CLOCK

3.2.2 Clock Source

The ESP32 can use an external crystal oscillator, an internal PLL or an oscillating circuit as a clock source.

Specifically, the clock sources available are:

• High Speed Clocks

– PLL_CLK is an internal PLL clock with a frequency of 320 MHz.

– XTL_CLK is a clock signal generated using an external crystal with a frequency range of 2 ~ 40 MHz.

• Low Power Clocks

– XTL32K_CLK is a clock generated using an external crystal with a frequency of 32 KHz.

– RTC8M_CLK is an internal clock with a default frequency of 8 MHz. This frequency is adjustable.

– RTC8M_D256_CLK is divided from RTC8M_CLK 256. Its frequency is (RTC8M_CLK / 256). With the

default RTC8M_CLK frequency of 8 MHz, this clock runs at 31.250 KHz.

– RTC_CLK is an internal low power clock with a default frequency of 150 KHz. This frequency is

adjustable.

• Audio Clock

– APLL_CLK is an internal Audio PLL clock with a frequency range of 16 ~ 128 MHz.

3.2.3 CPU Clock

As Figure 5 shows, CPU_CLK is the master clock for both CPU cores. CPU_CLK clock can be as high as 160

MHz when the CPU is in high performance mode. Alternatively, the CPU can run at lower frequencies to reduce

power consumption.

The CPU_CLK clock source is determined by the RTC_CNTL_SOC_CLK_SEL register. PLL_CLK, APLL_CLK,

RTC8M_CLK and XTL_CLK can be set as the CPU_CLK source; see Table 9 and 10.

Table 9: CPU_CLK Source

RTC_CNTL_SOC_CLK_SEL Value Clock Source

0 XTL_CLK

1 PLL_CLK

2 RTC8M_CLK

3 APLL_CLK

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3.2 System Clock 3 RESET AND CLOCK

Table 10: CPU_CLK Derivation

Clock Source SEL* CPU Clock

0 / XTL_CLK -

1 / PLL_CLK 0

1 / PLL_CLK 1

2 / RTC8M_CLK -

3 / APLL_CLK 0 CPU_CLK = APLL_CLK / 4

3 / APLL_CLK 1 CPU_CLK = APLL_CLK / 2

*SEL: DPORT_CPUPERIOD _SEL value

CPU_CLK = XTL_CLK / (APB_CTRL_PRE_DIV_CNT+1)

APB_CTRL_PRE_DIV_CNT range is 0 ~ 1023. Default is 0.

CPU_CLK = PLL_CLK / 4

CPU_CLK frequency is 80 MHz

CPU_CLK = PLL_CLK / 2

CPU_CLK frequency is 160 MHz

CPU_CLK = RTC8M_CLK / (APB_CTRL_PRE_DIV_CNT+1)

APB_CTRL_PRE_DIV_CNT range is 0 ~ 1023. Default is 0.

3.2.4 Peripheral Clock

Peripheral clocks include APB_CLK, REF_TICK, LEDC_SCLK, APLL_CLK and PLL_D2_CLK.

Table 11 shows which clocks can be used by which peripherals.

Table 11: Peripheral Clock Usage

Peripherals APB_CLK REF_TICK LEDC_SCLK APLL_CLK PLL_D2_CLK

EMAC Y N N Y N

TIMG Y N N N N

I2S Y N N Y Y

UART Y Y N N N

RMT Y Y N N N

LED PWM Y Y Y N N

PWM Y N N N N

I2C Y N N N N

SPI Y N N N N

PCNT Y N N N N

Efuse Controller Y N N N N

SDIO Slave Y N N N N

SDMMC Y N N N N

3.2.4.1 APB_CLK Source

The APB_CLK is derived from CPU_CLK as detailed in Table 12. The division factor depends on the CPU_CLK

source.

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3.2 System Clock 3 RESET AND CLOCK

Table 12: APB_CLK Derivation

CPU_CLK Source APB_CLK

PLL_CLK PLL_CLK / 4

APLL_CLK CPU_CLK / 2

XTAL_CLK CPU_CLK

RTC8M_CLK CPU_CLK

3.2.4.2 REF_TICK Source

REF_TICK is derived from APB_CLK via a divider. The divider value used depends on the APB_CLK source,

which in turn depends on the CPU_CLK source.

By configuring correct divider values for each APB_CLK source, the user can ensure that the REF_TICK

frequency does not change when CPU_CLK changes source causing the APB_CLK frequency to change.

Clock divider registers are shown in Table 13.

Table 13: REF_TICK Derivation

CPU_CLK & APB_CLK Source Clock Divider Register

PLL_CLK APB_CTRL_PLL_TICK_NUM

XTAL_CLK APB_CTRL_XTAL_TICK_NUM

APLL_CLK APB_CTRL_APLL_TICK_NUM

RTC8M_CLK APB_CTRL_CK8M_TICK_NUM

3.2.4.3 LEDC_SCLK Source

The LEDC_SCLK clock source is selected by the LEDC_APB_CLK_SEL register, as shown in Table 14.

Table 14: LEDC_SCLK Derivation

LEDC_APB_CLK_SEL Value LEDC_SCLK Source

1 RTC8M_CLK

0 APB_CLK

3.2.4.4 APLL_SCLK Source

The APLL_CLK is sourced from PLL_CLK, with its output frequency configured using the APLL configuration

registers.

3.2.4.5 PLL_D2_CLK Source

PLL_D2_CLK is half the PLL_CLK frequency.

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3.2 System Clock 3 RESET AND CLOCK

3.2.4.6 Clock Source Considerations

Most peripherals will operate using the APB_CLK frequency as a reference. When this frequency changes, the

peripherals will need to update their clock configuration to operate at the same frequency after the change.

Peripherals accessing REF_TICK can continue operating normally when switching clock sources, without

changing clock source. Please refer to Table 11 for details.

The LED PWM module can use RTC8M_CLK as a clock source, meaning that it can be used when APB_CLK is

disabled. In other words, when the system is in low power consumption mode (refer to power manager module),

normal peripherals will be halted (APB_CLK is turned off), but the LED PWM can work normally via

RTC8M_CLK.

3.2.5 Wi-Fi BT Clock

Wi-Fi and BT can only operate if APB_CLK has PLL_CLK as its clock source. Suspending PLL_CLK requires

Wi-Fi and BT to both have entered low power consumption mode first.

For LOW_POWER_CLK, one of RTC_CLK, SLOW_CLK, RTC8M_CLK or XTL_CLK can be selected as the low

power consumption mode clock source for Wi-Fi and BT.

3.2.6 RTC Clock

The clock sources of SLOW_CLK and FAST_CLK are low frequency clocks. The RTC module can operate when

most other clocks are stopped.

SLOW_CLK is used to clock the Power Management module. It can be sourced from RTC_CLK, XTL32K_CLK

or RTC8M_D256_CLK

FAST_CLK is used to clock the On-chip Sensor module. It can be sourced from a divided XTL_CLK or from

RTC8M_CLK.

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4 IO_MUX AND GPIO MATRIX

4. IO_MUX and GPIO Matrix

4.1 Introduction

The ESP32 chip features 40 physical GPIO pads. Some GPIO pads cannot be used or do not have the

corresponding pin on the chip package. Each pad can be used as a general purpose I/O or can be connected to

an internal peripheral signal. The IO_MUX, RTC IO_MUX and the GPIO matrix are responsible for routing signals

from the peripherals to GPIO pads. Together these systems provide highly configurable I/O.

This chapter describes the signal selection and connection between the digital pads (FUNC_SEL, IE, OE, WPU,

WDU, etc), 256 peripheral input/output signals (control signals: SIG_IN_SEL, SIG_OUT_SEL, IE, OE, etc), fast

peripheral input/output signals (control signals: SIG_IN_SEL, SIG_OUT_SEL, IE, OE, etc), and RTC

IO_MUX.

Figure 6: IO_MUX, RTC IO_MUX and GPIO Matrix Overview

1. The IO_MUX contains one register per GPIO pad. Each pad can be configured for ”GPIO” function

(connected to the GPIO Matrix) or configured for a direct function (bypassing the GPIO Matrix. Some high

speed digital functions (Ethernet, SDIO, SPI, JTAG, UART) can bypass the GPIO Matrix for better high

frequency digital performance. In this case, the IO_MUX is used to connect these pads directly to the

peripheral.)

Refer to Section 4.10 for a list of IO_MUX functions for each I/O pad.

2. The GPIO Matrix is a full switching matrix between the peripheral input/output signals and the pads.

• For input to the chip: Each of the 256 internal peripheral inputs can select any GPIO pad as the input

source.

• For output from the chip: The output signal of each of the 40 GPIO pads can be from one of the 256

peripheral output signals.

Refer to Section 4.9 for a list of GPIO Matrix peripheral signals.

3. RTC IO_MUX is used to connect GPIO pads to their low power and analog functions. Only a subset of

GPIO pads have these optional ”RTC” functions.

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4.2 Peripheral Input via GPIO Matrix 4 IO_MUX AND GPIO MATRIX

GPIO_FUNCy_IN_SEL

GPIO0_in

GPIO1_in GPIO2_in

GPIO3_in

GPIO39_in

0 (FUNC)

1 (FUNC)

2 (GPIO)

Peripheral Signal Y

I/O Pad X

In GPIO matrix

In IO MUX

GPIO X in

GPIOx_MCU_SEL

GPIOX_in

Constant 0 input Constant 1 input

(0x30) 48 (0x38) 56

1 (GPIO)

GPIO_SIGxx_IN_SEL

GPIOx_FUN_IE = 1

Refer to Section 4.11 for a list of RTC IO_MUX functions.

4.2 Peripheral Input via GPIO Matrix

4.2.1 Summary

To receive a peripheral input signal via the GPIO Matrix, the GPIO Matrix is configured to source the peripheral

signal’s input index (0-255) from one of the 40 GPIOs (0-39).

The input signal is read from the GPIO pad through the IO_MUX. The IO_MUX must be configured to set the

chosen pad to ”GPIO” function. This causes the GPIO pad input signal to be routed into the GPIO Matrix which

in turn routes it to the selected peripheral input.

4.2.2 Functional Description

Figure 7 shows the logic for input selection via GPIO Matrix.

To read GPIO pad X into peripheral signal Y, follow these steps:

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Figure 7: Peripheral Input via IO_MUX, GPIO Matrix

1. Configure the GPIO_FUNCy_IN_SEL_CFG register for peripheral signal Y in the GPIO Matrix:

• Set the GPIO_FUNCx_IN_SEL field to the number of the GPIO pad X to read from.

2. Configure the GPIO_FUNCx_OUT_SEL_CFG and GPIO_ENABLE_DATA[x] for GPIO pad X in the GPIO

Matrix:

• For input ony signals, the pad output can be disabled by setting the GPIO_FUNCx_OEN_SEL bits to

one and GPIO_ENABLE_DATA[x] to zero. Otherwise, there is no need to disable output.

3. Configure the IO_MUX register for GPIO pad X:

• Set the function field to GPIO.

• Enable the input by setting the xx_FUN_IE bit.

• Set xx_FUN_WPU and xx_FUN_WPD fields as desired to enable internal pull-up/pull-down resistors.

4.3 Peripheral Output via GPIO Matrix 4 IO_MUX AND GPIO MATRIX

Notes:

• One input pad can be connected to multiple input_signals.

• The input signal can be inverted with GPIO_FUNCx_IN_INV_SEL.

• It is possible to have a peripheral read a constant low or constant high input value without connecting this

input to a pad. This can be done by selecting a special GPIO_FUNCy_IN_SEL input instead of a GPIO

number:

– When GPIO_FUNCx_IN_SEL is 0x30, input_signal_x is always 0

– When GPIO_FUNCx_IN_SEL is 0x38, input_signal_x is always 1.

4.2.3 Simple GPIO Input

The GPIO_IN_DATA register holds the input values of each GPIO pad.

The input value of any GPIO pin can be read at any time without configuring the GPIO Matrix for a particular

peripheral signal. However, it is necessary to configure the xx_FUN_IE register for pad X, as shown in Section

4.2.2.

4.3 Peripheral Output via GPIO Matrix

4.3.1 Summary

To output a signal from a peripheral via the GPIO Matrix, the GPIO Matrix is configured to route the peripheral

output signal (0-255) to one of the first 34 GPIOs (0-33). (Note that GPIO pads 34-39 cannot be used as

outputs.)

The output signal is routed from the peripheral into the GPIO Matrix. It is then routed into the IO_MUX, which is

configured to set the chosen pad to ”GPIO” function. This causes the output GPIO signal to be connected to the

pad.

4.3.2 Functional Description

One of 256 input signals can be selected to go through the GPIO matrix into the IO_MUX and then to a pad.

Figure 8 illustrates the configuration.

To output peripheral signal Y to particular GPIO pad X, follow these steps:

1. Configure the GPIO_FUNCx_OUT_SEL_CFG register and GPIO_ENABLE_DATA[x] of GPIO X in the GPIO

Matrix:

• Set GPIO_FUNCx_OUT_SEL to the index of desired peripheral output signal Y.

• Set the GPIO_FUNCx_OEN_SEL bits and GPIO_ENABLE_DATA[x] to enable output mode by force,

OR, clear GPIO_FUNCx_OEN_SEL to zero so that the output enable signal will be decided by the

internal logic function.

2. Optionally, to enable open drain mode set the GPIO_PINx_PAD_DRIVER bit in the GPIO_PINx register.

3. Configure the I/O mux register for GPIO pad X:

• Set the function field to GPIO.

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4.4 Direct I/O via IO_MUX 4 IO_MUX AND GPIO MATRIX

GPIO_FUNCx_OUT_SEL

signal0_out signal1_out signal2_out signal3_out

signal255_out

GPIO_OUT_DATA bit x

0 1 2 3

255

256

(0x100)

GPIOx_out

In GPIO matrix

In IO MUX

0 (FUNC) 1 (FUNC)

2 (GPIO)

I/O Pad X

GPIO X out

GPIOx_MCU_SEL

GPIOx_FUN_OE = 1

• Set the xx_FUN_DRV field to the desired value for output strength. The higher the value is, the higher

the output strength is. Pull up/down the pad by configuring xx_FUNC_WPU and xx_FUNC_WPD

registers in open drain mode.

Notes:

• The output signal from a single peripheral can be sent to multiple pads simultaneously.

• Only the first 34 GPIOs (0-33) can be used as outputs.

• The output signal can be inverted by setting the GPIO_FUNCx_OUT_INV_SEL bit.

Figure 8: Output via GPIO Matrix

4.3.3 Simple GPIO Output

The GPIO Matrix can also be used for simple GPIO output - setting a bit in the GPIO_OUT_DATA register will

write to the corresponding GPIO pad.

To configure a pad as simple GPIO output, the GPIO Matrix GPIO_FUNCx_OUT_SEL register is configured with a

special peripheral index value (0x100).

4.4 Direct I/O via IO_MUX

4.4.1 Summary

Some high speed digital functions (Ethernet, SDIO, SPI, JTAG, UART) can bypass the GPIO Matrix for better high

frequency digital performance. In this case, the IO_MUX is used to connect these pads directly to the

peripheral.

Selecting this option is less flexible than using the GPIO Matrix, as the IO_MUX register for each GPIO pad can

only select from a limited number of functions. However, better high frequency digital performance will be

maintained.

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4.6 Light-sleep Mode Pin Functions 4 IO_MUX AND GPIO MATRIX

4.4.2 Functional Description

Two registers must be configured in order to bypass the GPIO Matrix for peripheral I/O:

1. IO_MUX for the GPIO pad must be set to the desired pad function (Section 4.10 has a list of pad functions).

2. For inputs, the SIG_IN_SEL register must be set to route the input directly to the peripheral.

4.5 RTC IO_MUX for Low Power and Analog I/O

4.5.1 Summary

18 pins have low power (RTC domain) capabilities and analog functions which are handled by the RTC

subsystem of ESP32. The IO_MUX and GPIO Matrix are not used for these functions, instead the RTC_MUX is

used to redirect the I/O to the RTC subsystem.

When configured as RTC GPIOs, the output pads can still retain the output level value when the chip is in

Deep-sleep mode, and the input pads can wake up the chip from Deep-sleep.

Section 4.11 has a list of RTC_MUX pins and their functions.

4.5.2 Functional Description

Each pad with analog and RTC functions is controlled by the RTC_IO_TOUCH_PADx_TO_GPIO bit in the

RTC_GPIO_PINx register. By default this bit is set to 1, routing all I/O via the IO_MUX subsystem as described in

earlier subsections.

If the RTC_IO_TOUCH_PADx_TO_GPIO bit is cleared, then I/O to and from that pad is routed to the RTC

subsystem instead. In this mode, the RTC_GPIO_PINx register is used for digital I/O and the analog features of

the pad are also available. See Section 4.11 for a list of RTC pin functions.

See 4.11 for a table mapping GPIO pads to their RTC equivalent pins and analog functions. Note that the

RTC_IO_PINx registers use the RTC GPIO pin numbering, not the GPIO pad numbering.

4.6 Light-sleep Mode Pin Functions

Pins can have different functions when the ESP32 is in Light-sleep mode. If the GPIOxx_SLP_SEL bit in the

IO_MUX register for a GPIO pad is set to 1, a different set of registers is used to control the pad when the ESP32

is in Light-sleep mode:

Table 15: IO_MUX Light-sleep Pin Function Registers

IO_MUX Function

Output Drive Strength GPIOxx_FUNC_DRV GPIOxx_MCU_DRV

Pullup Resistor GPIOxx_FUNC_WPU GPIOxx_MCU_WPU

Pulldown Resistor GPIOxx_FUNC_WPD GPIOxx_MCU_WPD

Output Enable (From GPIO Matrix _OEN field) GPIOxx_MCU_OE

If GPIOxx_SLP_SEL is set to 0, the pin functions remain the same in both normal execution and Light-sleep

modes.

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Normal Execution Light-sleep Mode

OR GPIOxx_SLP_SEL = 0 AND GPIOxx_SLP_SEL = 1

4.7 Pad Hold Feature 4 IO_MUX AND GPIO MATRIX

4.7 Pad Hold Feature

Each IO pad (including the RTC pads) has an individual hold function controlled by a RTC register. When the pad

is set to hold, the state is latched at that moment and will not change no matter how the internal signals change

or how the IO_MUX configuration or GPIO configuration is modified. Users can use the hold function for the pads

to retain the pad state through a core reset and system reset triggered by watchdog time-out or Deep-sleep

events.

4.8 I/O Pad Power Supply

IO pad power supply is shown in Figure 9.

Figure 9: ESP32 I/O Pad Power Sources

• Pads marked blue are RTC pads that have their individual analog function and can also act as normal

digital IO pads. For details, please refer to Section 4.11.

• Pads marked pink and green only have digital functions.

• Pads marked green can be powered externally or internally via VDD_SDIO (see below).

4.8.1 VDD_SDIO Power Domain

VDD_SDIO can source or sink current, allowing this power domain to be powered externally or internally. To

power VDD_SDIO externally, apply the same power supply of VDD3P3_RTC to the VDD_SDIO pad.

Without an external power supply, the internal regulator will supply VDD_SDIO. The VDD_SDIO voltage can be

configured to be either 1.8V or 3.3V (the same as that at VRTC), depending on the state of the MTDI pad at reset

- a high level configures 1.8V and a low level configures 3.3V. Setting the efuse bit decides the default voltage of

the VDD_SDIO. In addition, software can change the voltage of the VDD_SDIO by configuring register bits.

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4.9 Peripheral Signal List 4 IO_MUX AND GPIO MATRIX

4.9 Peripheral Signal List

Table 16 contains a list of Peripheral Input/Output signals used by the GPIO Matrix:

Table 16: GPIO Matrix Peripheral Signals

Signal Input Signal Output Signal Direct I/O in IO_MUX

0 SPICLK_in SPICLK_out YES

1 SPIQ_in SPIQ_out YES

2 SPID_in SPID_out YES

3 SPIHD_in SPIHD_out YES

4 SPIWP_in SPIWP_out YES

5 SPICS0_in SPICS0_out YES

6 SPICS1_in SPICS1_out

7 SPICS2_in SPICS2_out

8 HSPICLK_in HSPICLK_out YES

9 HSPIQ_in HSPIQ_out YES

10 HSPID_in HSPID_out YES

11 HSPICS0_in HSPICS0_out YES

12 HSPIHD_in HSPIHD_out YES

13 HSPIWP_in HSPIWP_out YES

14 U0RXD_in U0TXD_out YES

15 U0CTS_in U0RTS_out YES

16 U0DSR_in U0DTR_out

17 U1RXD_in U1TXD_out YES

18 U1CTS_in U1RTS_out YES

23 I2S0O_BCK_in I2S0O_BCK_out

24 I2S1O_BCK_in I2S1O_BCK_out

25 I2S0O_WS_in I2S0O_WS_out

26 I2S1O_WS_in I2S1O_WS_out

27 I2S0I_BCK_in I2S0I_BCK_out

28 I2S0I_WS_in I2S0I_WS_out

29 I2CEXT0_SCL_in I2CEXT0_SCL_out

30 I2CEXT0_SDA_in I2CEXT0_SDA_out

31 pwm0_sync0_in sdio_tohost_int_out

32 pwm0_sync1_in pwm0_out0a

33 pwm0_sync2_in pwm0_out0b

34 pwm0_f0_in pwm0_out1a

35 pwm0_f1_in pwm0_out1b

36 pwm0_f2_in pwm0_out2a

37 pwm0_out2b

39 pcnt_sig_ch0_in0

40 pcnt_sig_ch1_in0

41 pcnt_ctrl_ch0_in0

42 pcnt_ctrl_ch1_in0

43 pcnt_sig_ch0_in1

44 pcnt_sig_ch1_in1

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4.9 Peripheral Signal List 4 IO_MUX AND GPIO MATRIX

Signal Input Signal Output Signal Direct I/O in IO_MUX

45 pcnt_ctrl_ch0_in1

46 pcnt_ctrl_ch1_in1

47 pcnt_sig_ch0_in2

48 pcnt_sig_ch1_in2

49 pcnt_ctrl_ch0_in2

50 pcnt_ctrl_ch1_in2

51 pcnt_sig_ch0_in3

52 pcnt_sig_ch1_in3

53 pcnt_ctrl_ch0_in3

54 pcnt_ctrl_ch1_in3

55 pcnt_sig_ch0_in4

56 pcnt_sig_ch1_in4

57 pcnt_ctrl_ch0_in4

58 pcnt_ctrl_ch1_in4

61 HSPICS1_in HSPICS1_out

62 HSPICS2_in HSPICS2_out

63 VSPICLK_in VSPICLK_out_mux YES

64 VSPIQ_in VSPIQ_out YES

65 VSPID_in VSPID_out YES

66 VSPIHD_in VSPIHD_out YES

67 VSPIWP_in VSPIWP_out YES

68 VSPICS0_in VSPICS0_out YES

69 VSPICS1_in VSPICS1_out

70 VSPICS2_in VSPICS2_out

71 pcnt_sig_ch0_in5 ledc_hs_sig_out0

72 pcnt_sig_ch1_in5 ledc_hs_sig_out1

73 pcnt_ctrl_ch0_in5 ledc_hs_sig_out2

74 pcnt_ctrl_ch1_in5 ledc_hs_sig_out3

75 pcnt_sig_ch0_in6 ledc_hs_sig_out4

76 pcnt_sig_ch1_in6 ledc_hs_sig_out5

77 pcnt_ctrl_ch0_in6 ledc_hs_sig_out6

78 pcnt_ctrl_ch1_in6 ledc_hs_sig_out7

79 pcnt_sig_ch0_in7 ledc_ls_sig_out0

80 pcnt_sig_ch1_in7 ledc_ls_sig_out1

81 pcnt_ctrl_ch0_in7 ledc_ls_sig_out2

82 pcnt_ctrl_ch1_in7 ledc_ls_sig_out3

83 rmt_sig_in0 ledc_ls_sig_out4

84 rmt_sig_in1 ledc_ls_sig_out5

85 rmt_sig_in2 ledc_ls_sig_out6

86 rmt_sig_in3 ledc_ls_sig_out7

87 rmt_sig_in4 rmt_sig_out0

88 rmt_sig_in5 rmt_sig_out1

89 rmt_sig_in6 rmt_sig_out2

90 rmt_sig_in7 rmt_sig_out3

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4.9 Peripheral Signal List 4 IO_MUX AND GPIO MATRIX

Signal Input Signal Output Signal Direct I/O in IO_MUX

91 rmt_sig_out4

92 rmt_sig_out5

93 rmt_sig_out6

94 rmt_sig_out7

95 I2CEXT1_SCL_in I2CEXT1_SCL_out

96 I2CEXT1_SDA_in I2CEXT1_SDA_out

97 host_card_detect_n_1 host_ccmd_od_pullup_en_n

98 host_card_detect_n_2 host_rst_n_1

99 host_card_write_prt_1 host_rst_n_2

100 host_card_write_prt_2 gpio_sd0_out

101 host_card_int_n_1 gpio_sd1_out

102 host_card_int_n_2 gpio_sd2_out

103 pwm1_sync0_in gpio_sd3_out

104 pwm1_sync1_in gpio_sd4_out

105 pwm1_sync2_in gpio_sd5_out

106 pwm1_f0_in gpio_sd6_out

107 pwm1_f1_in gpio_sd7_out

108 pwm1_f2_in pwm1_out0a

109 pwm0_cap0_in pwm1_out0b

110 pwm0_cap1_in pwm1_out1a

111 pwm0_cap2_in pwm1_out1b

112 pwm1_cap0_in pwm1_out2a

113 pwm1_cap1_in pwm1_out2b

114 pwm1_cap2_in pwm2_out1h

115 pwm2_flta pwm2_out1l

116 pwm2_fltb pwm2_out2h

117 pwm2_cap1_in pwm2_out2l

118 pwm2_cap2_in pwm2_out3h

119 pwm2_cap3_in pwm2_out3l

120 pwm3_flta pwm2_out4h

121 pwm3_fltb pwm2_out4l

122 pwm3_cap1_in

123 pwm3_cap2_in

124 pwm3_cap3_in

140 I2S0I_DATA_in0 I2S0O_DATA_out0

141 I2S0I_DATA_in1 I2S0O_DATA_out1

142 I2S0I_DATA_in2 I2S0O_DATA_out2

143 I2S0I_DATA_in3 I2S0O_DATA_out3

144 I2S0I_DATA_in4 I2S0O_DATA_out4

145 I2S0I_DATA_in5 I2S0O_DATA_out5

146 I2S0I_DATA_in6 I2S0O_DATA_out6

147 I2S0I_DATA_in7 I2S0O_DATA_out7

148 I2S0I_DATA_in8 I2S0O_DATA_out8

149 I2S0I_DATA_in9 I2S0O_DATA_out9

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4.9 Peripheral Signal List 4 IO_MUX AND GPIO MATRIX

Signal Input Signal Output Signal Direct I/O in IO_MUX

150 I2S0I_DATA_in10 I2S0O_DATA_out10

151 I2S0I_DATA_in11 I2S0O_DATA_out11

152 I2S0I_DATA_in12 I2S0O_DATA_out12

153 I2S0I_DATA_in13 I2S0O_DATA_out13

154 I2S0I_DATA_in14 I2S0O_DATA_out14

155 I2S0I_DATA_in15 I2S0O_DATA_out15

156 I2S0O_DATA_out16

157 I2S0O_DATA_out17

158 I2S0O_DATA_out18

159 I2S0O_DATA_out19

160 I2S0O_DATA_out20

161 I2S0O_DATA_out21

162 I2S0O_DATA_out22

163 I2S0O_DATA_out23

164 I2S1I_BCK_in I2S1I_BCK_out

165 I2S1I_WS_in I2S1I_WS_out

166 I2S1I_DATA_in0 I2S1O_DATA_out0

167 I2S1I_DATA_in1 I2S1O_DATA_out1

168 I2S1I_DATA_in2 I2S1O_DATA_out2

169 I2S1I_DATA_in3 I2S1O_DATA_out3

170 I2S1I_DATA_in4 I2S1O_DATA_out4

171 I2S1I_DATA_in5 I2S1O_DATA_out5

172 I2S1I_DATA_in6 I2S1O_DATA_out6

173 I2S1I_DATA_in7 I2S1O_DATA_out7

174 I2S1I_DATA_in8 I2S1O_DATA_out8

175 I2S1I_DATA_in9 I2S1O_DATA_out9

176 I2S1I_DATA_in10 I2S1O_DATA_out10

177 I2S1I_DATA_in11 I2S1O_DATA_out11

178 I2S1I_DATA_in12 I2S1O_DATA_out12

179 I2S1I_DATA_in13 I2S1O_DATA_out13

180 I2S1I_DATA_in14 I2S1O_DATA_out14

181 I2S1I_DATA_in15 I2S1O_DATA_out15

182 I2S1O_DATA_out16

183 I2S1O_DATA_out17

184 I2S1O_DATA_out18

185 I2S1O_DATA_out19

186 I2S1O_DATA_out20

187 I2S1O_DATA_out21

188 I2S1O_DATA_out22

189 I2S1O_DATA_out23

190 I2S0I_H_SYNC pwm3_out1h

191 I2S0I_V_SYNC pwm3_out1l

192 I2S0I_H_ENABLE pwm3_out2h

193 I2S1I_H_SYNC pwm3_out2l

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4.10 IO_MUX Pad List 4 IO_MUX AND GPIO MATRIX

Signal Input Signal Output Signal Direct I/O in IO_MUX

194 I2S1I_V_SYNC pwm3_out3h

195 I2S1I_H_ENABLE pwm3_out3l

196 pwm3_out4h

197 pwm3_out4l

198 U2RXD_in U2TXD_out YES

199 U2CTS_in U2RTS_out YES

200 emac_mdc_i emac_mdc_o

201 emac_mdi_i emac_mdo_o

202 emac_crs_i emac_crs_o

203 emac_col_i emac_col_o

204 pcmfsync_in bt_audio0_irq

205 pcmclk_in bt_audio1_irq

206 pcmdin bt_audio2_irq

207 ble_audio0_irq

208 ble_audio1_irq

209 ble_audio2_irq

210 pcmfsync_out

211 pcmclk_out

212 pcmdout

213 ble_audio_sync0_p

214 ble_audio_sync1_p

215 ble_audio_sync2_p

224 sig_in_func224

225 sig_in_func225

226 sig_in_func226

227 sig_in_func227

228 sig_in_func228

Direct I/O in IO_MUX ”YES” means this signal is also available directly via IO_MUX. To apply GPIO Matrix for

these signals, their corresponding SIG_IN_SEL register must be cleared.

4.10 IO_MUX Pad List

Table 17 shows the IO_MUX functions for each I/O pad:

Table 17: IO_MUX Pad Summary

GPIO Pad Name Function 1 Function 2 Function 3 Function 4 Function 5 Function 6 Reset Notes

0 GPIO0 GPIO0 CLK_OUT1 GPIO0 - - EMAC_TX_CLK 3 R

1 U0TXD U0TXD CLK_OUT3 GPIO1 - - EMAC_RXD2 3 -

2 GPIO2 GPIO2 HSPIWP GPIO2 HS2_DATA0 SD_DATA0 - 2 R

3 U0RXD U0RXD CLK_OUT2 GPIO3 - - - 3 -

4 GPIO4 GPIO4 HSPIHD GPIO4 HS2_DATA1 SD_DATA1 EMAC_TX_ER 2 R

5 GPIO5 GPIO5 VSPICS0 GPIO5 HS1_DATA6 - EMAC_RX_CLK 3 -

6 SD_CLK SD_CLK SPICLK GPIO6 HS1_CLK U1CTS - 3 -

7 SD_DATA_0 SD_DATA0 SPIQ GPIO7 HS1_DATA0 U2RTS - 3 -

8 SD_DATA_1 SD_DATA1 SPID GPIO8 HS1_DATA1 U2CTS - 3 -

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4.11 RTC_MUX Pin List 4 IO_MUX AND GPIO MATRIX

GPIO Pad Name Function 1 Function 2 Function 3 Function 4 Function 5 Function 6 Reset Notes

9 SD_DATA_2 SD_DATA2 SPIHD GPIO9 HS1_DATA2 U1RXD - 3 -

10 SD_DATA_3 SD_DATA3 SPIWP GPIO10 HS1_DATA3 U1TXD - 3 -

11 SD_CMD SD_CMD SPICS0 GPIO11 HS1_CMD U1RTS - 3 -

12 MTDI MTDI HSPIQ GPIO12 HS2_DATA2 SD_DATA2 EMAC_TXD3 2 R

13 MTCK MTCK HSPID GPIO13 HS2_DATA3 SD_DATA3 EMAC_RX_ER 1 R

14 MTMS MTMS HSPICLK GPIO14 HS2_CLK SD_CLK EMAC_TXD2 1 R

15 MTDO MTDO HSPICS0 GPIO15 HS2_CMD SD_CMD EMAC_RXD3 3 R

16 GPIO16 GPIO16 - GPIO16 HS1_DATA4 U2RXD EMAC_CLK_OUT 1 -

17 GPIO17 GPIO17 - GPIO17 HS1_DATA5 U2TXD EMAC_CLK_180 1 -

18 GPIO18 GPIO18 VSPICLK GPIO18 HS1_DATA7 - - 1 -

19 GPIO19 GPIO19 VSPIQ GPIO19 U0CTS - EMAC_TXD0 1 -

20 GPIO20 GPIO20 - GPIO20 - - - 1 -

21 GPIO21 GPIO21 VSPIHD GPIO21 - - EMAC_TX_EN 1 -

22 GPIO22 GPIO22 VSPIWP GPIO22 U0RTS - EMAC_TXD1 1 -

23 GPIO23 GPIO23 VSPID GPIO23 HS1_STROBE - - 1 -

25 GPIO25 GPIO25 - GPIO25 - - EMAC_RXD0 0 R

26 GPIO26 GPIO26 - GPIO26 - - EMAC_RXD1 0 R

27 GPIO27 GPIO27 - GPIO27 - - EMAC_RX_DV 1 R

32 32K_XP GPIO32 - GPIO32 - - - 0 R

33 32K_XN GPIO33 - GPIO33 - - - 0 R

34 VDET_1 GPIO34 - GPIO34 - - - 0 R, I

35 VDET_2 GPIO35 - GPIO35 - - - 0 R, I

36 SENSOR_VP GPIO36 - GPIO36 - - - 0 R, I

37 SENSOR_CAPP GPIO37 - GPIO37 - - - 0 R, I

38 SENSOR_CAPN GPIO38 - GPIO38 - - - 0 R, I

39 SENSOR_VN GPIO39 - GPIO39 - - - 0 R, I

Reset Configurations

”Reset” column shows each pad’s default configurations after reset:

• 0 - IE=0 (input disabled).

• 1 - IE=1 (input enabled).

• 2 - IE=1, WPD=1 (input enabled, pulldown resistor).

• 3 - IE=1, WPU=1 (input enabled, pullup resistor).

Notes

• R - Pad has RTC/analog functions via RTC_MUX.

• I - Pad can only be configured as input GPIO.

Refer to ESP32 Pin List datasheet for more details and a complete table of pin functions.

4.11 RTC_MUX Pin List

Table 18 shows the RTC pins and how they correspond to GPIO pads:

Table 18: RTC_MUX Pin Summary

RTC GPIO Num GPIO Num Pad Name

1 2 3

Analog Function

0 36 SENSOR_VP ADC_H ADC1_CH0 -

1 37 SENSOR_CAPP ADC_H ADC1_CH1 -

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4.12 Register Summary 4 IO_MUX AND GPIO MATRIX

RTC GPIO Num GPIO Num Pad Name

2 38 SENSOR_CAPN ADC_H ADC1_CH2 -

3 39 SENSOR_VN ADC_H ADC1_CH3 -

4 34 VDET_1 - ADC1_CH6 -

5 35 VDET_2 - ADC1_CH7 -

6 25 GPIO25 DAC_1 ADC2_CH8 -

7 26 GPIO26 DAC_2 ADC2_CH9 -

8 33 32K_XN XTAL_32K_N ADC1_CH5 TOUCH8

9 32 32K_XP XTAL_32K_P ADC1_CH4 TOUCH9

10 4 GPIO4 - ADC2_CH0 TOUCH0

11 0 GPIO0 - ADC2_CH1 TOUCH1

12 2 GPIO2 - ADC2_CH2 TOUCH2

13 15 MTDO - ADC2_CH3 TOUCH3

14 13 MTCK - ADC2_CH4 TOUCH4

15 12 MTDI - ADC2_CH5 TOUCH5

16 14 MTMS - ADC2_CH6 TOUCH6

17 27 GPIO27 - ADC2_CH7 TOUCH7

1 2 3

Analog Function

4.12 Register Summary

Name Description Address Access

GPIO_OUT_REG GPIO 0-31 output register_REG 0x3FF44004 R/W

GPIO_OUT_W1TS_REG GPIO 0-31 output register_W1TS_REG 0x3FF44008 RO

GPIO_OUT_W1TC_REG GPIO 0-31 output register_W1TC_REG 0x3FF4400C RO

GPIO_OUT1_REG GPIO 0-31 output register1_REG 0x3FF44010 R/W

GPIO_OUT1_W1TS_REG GPIO 0-31 output register1_W1TS_REG 0x3FF44014 RO

GPIO_OUT1_W1TC_REG GPIO 0-31 output register1_W1TC_REG 0x3FF44018 RO

GPIO_OUT_W1TS_REG GPIO 0-31 output bit set register_REG 0x3FF44008 RO

GPIO_OUT_W1TC_REG GPIO 0-31 output bit clear register_REG 0x3FF4400C RO

GPIO_OUT1_REG GPIO 32-39 output register_REG 0x3FF44010 R/W

GPIO_OUT1_W1TS_REG GPIO 32-39 output register_W1TS_REG 0x3FF44014 RO

GPIO_OUT1_W1TC_REG GPIO 32-39 output register_W1TC_REG 0x3FF44018 RO

GPIO_OUT1_W1TS_REG GPIO 32-39 output bit set register_REG 0x3FF44014 RO

GPIO_OUT1_W1TC_REG GPIO 32-39 output bit clear register_REG 0x3FF44018 RO

GPIO_ENABLE_REG GPIO 0-31 output enable register_REG 0x3FF44020 R/W

GPIO_ENABLE_W1TS_REG GPIO 0-31 output enable register_W1TS_REG 0x3FF44024 RO

GPIO_ENABLE_W1TC_REG GPIO 0-31 output enable register_W1TC_REG 0x3FF44028 RO

GPIO_ENABLE1_REG GPIO 0-31 output enable register1_REG 0x3FF4402C R/W

GPIO_ENABLE1_W1TS_REG GPIO 0-31 output enable register1_W1TS_REG 0x3FF44030 RO

GPIO_ENABLE1_W1TC_REG GPIO 0-31 output enable register1_W1TC_REG 0x3FF44034 RO

GPIO_ENABLE_W1TS_REG GPIO 0-31 output enable bit set register_REG 0x3FF44024 RO

GPIO_ENABLE_W1TC_REG GPIO 0-31 output enable bit clear register_REG 0x3FF44028 RO

GPIO_ENABLE1_REG GPIO 32-39 output enable register_REG 0x3FF4402C R/W

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4.12 Register Summary 4 IO_MUX AND GPIO MATRIX

Name Description Address Access

GPIO_ENABLE1_W1TS_REG GPIO 32-39 output enable register_W1TS_REG 0x3FF44030 RO

GPIO_ENABLE1_W1TC_REG GPIO 32-39 output enable register_W1TC_REG 0x3FF44034 RO

GPIO_ENABLE1_W1TS_REG GPIO 32-39 output enable bit set register_REG 0x3FF44030 RO

GPIO_ENABLE1_W1TC_REG GPIO 32-39 output enable bit clear register_REG 0x3FF44034 RO

GPIO_STRAP_REG Bootstrap pin value register_REG 0x3FF44038 RO

GPIO_IN_REG GPIO 0-31 input register_REG 0x3FF4403C RO

GPIO_IN1_REG GPIO 0-31 input register1_REG 0x3FF44040 RO

GPIO_IN1_REG GPIO 32-39 input register_REG 0x3FF44040 RO

GPIO_STATUS_REG GPIO 0-31 interrupt status register_REG 0x3FF44044 R/W

GPIO_STATUS_W1TS_REG GPIO 0-31 interrupt status register_W1TS_REG 0x3FF44048 RO

GPIO_STATUS_W1TC_REG GPIO 0-31 interrupt status register_W1TC_REG 0x3FF4404C RO

GPIO_STATUS1_REG GPIO 0-31 interrupt status register1_REG 0x3FF44050 R/W

GPIO_STATUS1_W1TS_REG GPIO 0-31 interrupt status register1_W1TS_REG 0x3FF44054 RO

GPIO_STATUS1_W1TC_REG GPIO 0-31 interrupt status register1_W1TC_REG 0x3FF44058 RO

GPIO_STATUS_W1TS_REG GPIO 0-31 interrupt status bit set register_REG 0x3FF44048 RO

GPIO_STATUS_W1TC_REG GPIO 0-31 interrupt status bit clear register_REG 0x3FF4404C RO

GPIO_STATUS1_REG GPIO 32-39 interrupt status register_REG 0x3FF44050 R/W

GPIO_STATUS1_W1TS_REG GPIO 32-39 interrupt status register_W1TS_REG 0x3FF44054 RO

GPIO_STATUS1_W1TC_REG GPIO 32-39 interrupt status register_W1TC_REG 0x3FF44058 RO

GPIO_STATUS1_W1TS_REG GPIO 32-39 interrupt status bit set register_REG 0x3FF44054 RO

GPIO_STATUS1_W1TC_REG GPIO 32-39 interrupt status bit clear register_REG 0x3FF44058 RO

GPIO_ACPU_INT_REG GPIO 0-31 APP_CPU interrupt status_REG 0x3FF44060 RO

GPIO_ACPU_INT1_REG GPIO 0-31 APP_CPU interrupt status1_REG 0x3FF44074 RO

GPIO_ACPU_NMI_INT_REG

GPIO_ACPU_NMI_INT1_REG

GPIO 0-31 APP_CPU non-maskable interrupt sta-

tus_REG

GPIO 0-31 APP_CPU non-maskable interrupt sta-

tus1_REG

0x3FF44064 RO

0x3FF44078 RO

GPIO_PCPU_INT_REG GPIO 0-31 PRO_CPU interrupt status_REG 0x3FF44068 RO

GPIO_PCPU_INT1_REG GPIO 0-31 PRO_CPU interrupt status1_REG 0x3FF4407C RO

GPIO_PCPU_NMI_INT_REG

GPIO_PCPU_NMI_INT1_REG

GPIO 0-31 PRO_CPU non-maskable interrupt sta-

tus_REG

GPIO 0-31 PRO_CPU non-maskable interrupt sta-

tus1_REG

0x3FF4406C RO

0x3FF44080 RO

GPIO_ACPU_INT1_REG GPIO 32-39 APP_CPU interrupt status_REG 0x3FF44074 RO

GPIO_ACPU_NMI_INT1_REG

GPIO 32-39 APP_CPU non-maskable interrupt

status_REG

0x3FF44078 RO

GPIO_PCPU_INT1_REG GPIO 32-39 PRO_CPU interrupt status_REG 0x3FF4407C RO

GPIO_PCPU_NMI_INT1_REG

GPIO 32-39 PRO_CPU non-maskable interrupt

status_REG

0x3FF44080 RO

GPIO_PIN0_REG Configuration for GPIO pin 0_REG 0x3FF44088 R/W

GPIO_PIN1_REG Configuration for GPIO pin 1_REG 0x3FF4408C R/W

GPIO_PIN2_REG Configuration for GPIO pin 2_REG 0x3FF44090 R/W

... ...

GPIO_PIN38_REG Configuration for GPIO pin 38_REG 0x3FF44120 R/W

Espressif Systems 41 ESP32 Technical Reference Manual V1.0

4.12 Register Summary 4 IO_MUX AND GPIO MATRIX

Name Description Address Access

GPIO_PIN39_REG Configuration for GPIO pin 39_REG 0x3FF44124 R/W

GPIO_FUNC0_IN_SEL_CFG_REG Peripheral function 0 input selection register_REG 0x3FF44130 R/W

GPIO_FUNC1_IN_SEL_CFG_REG Peripheral function 1 input selection register_REG 0x3FF44134 R/W

... ...

GPIO_FUNC254_IN_SEL_CFG_REG

GPIO_FUNC255_IN_SEL_CFG_REG

Peripheral function 254 input selection regis-

ter_REG

Peripheral function 255 input selection regis-

ter_REG

0x3FF44528 R/W

0x3FF4452C R/W

GPIO_FUNC0_OUT_SEL_CFG_REG Peripheral output selection for GPIO 0_REG 0x3FF44530 R/W

GPIO_FUNC1_OUT_SEL_CFG_REG Peripheral output selection for GPIO 1_REG 0x3FF44534 R/W

... ...

GPIO_FUNC38_OUT_SEL_CFG_REG Peripheral output selection for GPIO 38_REG 0x3FF445C8 R/W

GPIO_FUNC39_OUT_SEL_CFG_REG Peripheral output selection for GPIO 39_REG 0x3FF445CC R/W

Name Description Address Access

IO_MUX_GPIO36_REG Configuration register for pad GPIO36 0x3FF53004 R/W

IO_MUX_GPIO37_REG Configuration register for pad GPIO37 0x3FF53008 R/W

IO_MUX_GPIO38_REG Configuration register for pad GPIO38 0x3FF5300C R/W

IO_MUX_GPIO39_REG Configuration register for pad GPIO39 0x3FF53010 R/W

IO_MUX_GPIO34_REG Configuration register for pad GPIO34 0x3FF53014 R/W

IO_MUX_GPIO35_REG Configuration register for pad GPIO35 0x3FF53018 R/W

IO_MUX_GPIO32_REG Configuration register for pad GPIO32 0x3FF5301C R/W

IO_MUX_GPIO33_REG Configuration register for pad GPIO33 0x3FF53020 R/W

IO_MUX_GPIO25_REG Configuration register for pad GPIO25 0x3FF53024 R/W

IO_MUX_GPIO26_REG Configuration register for pad GPIO26 0x3FF53028 R/W

IO_MUX_GPIO27_REG Configuration register for pad GPIO27 0x3FF5302C R/W

IO_MUX_MTMS_REG Configuration register for pad MTMS 0x3FF53030 R/W

IO_MUX_MTDI_REG Configuration register for pad MTDI 0x3FF53034 R/W

IO_MUX_MTCK_REG Configuration register for pad MTCK 0x3FF53038 R/W

IO_MUX_MTDO_REG Configuration register for pad MTDO 0x3FF5303C R/W

IO_MUX_GPIO2_REG Configuration register for pad GPIO2 0x3FF53040 R/W

IO_MUX_GPIO0_REG Configuration register for pad GPIO0 0x3FF53044 R/W

IO_MUX_GPIO4_REG Configuration register for pad GPIO4 0x3FF53048 R/W

IO_MUX_GPIO16_REG Configuration register for pad GPIO16 0x3FF5304C R/W

IO_MUX_GPIO17_REG Configuration register for pad GPIO17 0x3FF53050 R/W

IO_MUX_SD_DATA2_REG Configuration register for pad SD_DATA2 0x3FF53054 R/W

IO_MUX_SD_DATA3_REG Configuration register for pad SD_DATA3 0x3FF53058 R/W

IO_MUX_SD_CMD_REG Configuration register for pad SD_CMD 0x3FF5305C R/W

IO_MUX_SD_CLK_REG Configuration register for pad SD_CLK 0x3FF53060 R/W

IO_MUX_SD_DATA0_REG Configuration register for pad SD_DATA0 0x3FF53064 R/W

IO_MUX_SD_DATA1_REG Configuration register for pad SD_DATA1 0x3FF53068 R/W

IO_MUX_GPIO5_REG Configuration register for pad GPIO5 0x3FF5306C R/W

IO_MUX_GPIO18_REG Configuration register for pad GPIO18 0x3FF53070 R/W

IO_MUX_GPIO19_REG Configuration register for pad GPIO19 0x3FF53074 R/W

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4.12 Register Summary 4 IO_MUX AND GPIO MATRIX

Name Description Address Access

IO_MUX_GPIO20_REG Configuration register for pad GPIO20 0x3FF53078 R/W

IO_MUX_GPIO21_REG Configuration register for pad GPIO21 0x3FF5307C R/W

IO_MUX_GPIO22_REG Configuration register for pad GPIO22 0x3FF53080 R/W

IO_MUX_U0RXD_REG Configuration register for pad U0RXD 0x3FF53084 R/W

IO_MUX_U0TXD_REG Configuration register for pad U0TXD 0x3FF53088 R/W

IO_MUX_GPIO23_REG Configuration register for pad GPIO23 0x3FF5308C R/W

IO_MUX_GPIO24_REG Configuration register for pad GPIO24 0x3FF53090 R/W

Name Description Address Access

GPIO configuration / data registers

RTCIO_RTC_GPIO_OUT_REG RTC GPIO output register_REG 0x3FF48000 R/W

RTCIO_RTC_GPIO_OUT_W1TS_REG RTC GPIO output register_W1TS_REG 0x3FF48001 WO

RTCIO_RTC_GPIO_OUT_W1TC_REG RTC GPIO output register_W1TC_REG 0x3FF48002 WO

RTCIO_RTC_GPIO_OUT_W1TS_REG RTC GPIO output bit set register_REG 0x3FF48001 WO

RTCIO_RTC_GPIO_OUT_W1TC_REG RTC GPIO output bit clear register_REG 0x3FF48002 WO

RTCIO_RTC_GPIO_ENABLE_REG RTC GPIO output enable register_REG 0x3FF48003 R/W

RTCIO_RTC_GPIO_ENABLE_W1TS_REG RTC GPIO output enable register_W1TS_REG 0x3FF48004 WO

RTCIO_RTC_GPIO_ENABLE_W1TC_REG RTC GPIO output enable register_W1TC_REG 0x3FF48005 WO

RTCIO_RTC_GPIO_ENABLE_W1TS_REG RTC GPIO output enable bit setregister_REG 0x3FF48004 WO

RTCIO_RTC_GPIO_ENABLE_W1TC_REG RTC GPIO output enable bit clear register_REG 0x3FF48005 WO

RTCIO_RTC_GPIO_STATUS_REG RTC GPIO interrupt status register_REG 0x3FF48006 R/W

RTCIO_RTC_GPIO_STATUS_W1TS_REG

RTCIO_RTC_GPIO_STATUS_W1TC_REG

RTC GPIO interrupt status regis-

ter_W1TS_REG

RTC GPIO interrupt status regis-

ter_W1TC_REG

0x3FF48007 WO

0x3FF48008 WO

RTCIO_RTC_GPIO_STATUS_W1TS_REG RTC GPIO interrupt status bit set register_REG 0x3FF48007 WO

RTCIO_RTC_GPIO_STATUS_W1TC_REG

RTC GPIO interrupt status bit clear regis-

ter_REG

0x3FF48008 WO

RTCIO_RTC_GPIO_IN_REG RTC GPIO input register_REG 0x3FF48009 RO

RTCIO_RTC_GPIO_PIN0_REG RTC configuration for pin 0_REG 0x3FF4800A R/W

RTCIO_RTC_GPIO_PIN1_REG RTC configuration for pin 1_REG 0x3FF4800B R/W

RTCIO_RTC_GPIO_PIN2_REG RTC configuration for pin 2_REG 0x3FF4800C R/W

RTCIO_RTC_GPIO_PIN3_REG RTC configuration for pin 3_REG 0x3FF4800D R/W

RTCIO_RTC_GPIO_PIN4_REG RTC configuration for pin 4_REG 0x3FF4800E R/W

RTCIO_RTC_GPIO_PIN5_REG RTC configuration for pin 5_REG 0x3FF4800F R/W

RTCIO_RTC_GPIO_PIN6_REG RTC configuration for pin 6_REG 0x3FF48010 R/W

RTCIO_RTC_GPIO_PIN7_REG RTC configuration for pin 7_REG 0x3FF48011 R/W

RTCIO_RTC_GPIO_PIN8_REG RTC configuration for pin 8_REG 0x3FF48012 R/W

RTCIO_RTC_GPIO_PIN9_REG RTC configuration for pin 9_REG 0x3FF48013 R/W

RTCIO_RTC_GPIO_PIN10_REG RTC configuration for pin 10_REG 0x3FF48014 R/W

RTCIO_RTC_GPIO_PIN11_REG RTC configuration for pin 11_REG 0x3FF48015 R/W

RTCIO_RTC_GPIO_PIN12_REG RTC configuration for pin 12_REG 0x3FF48016 R/W

RTCIO_RTC_GPIO_PIN13_REG RTC configuration for pin 13_REG 0x3FF48017 R/W

RTCIO_RTC_GPIO_PIN14_REG RTC configuration for pin 14_REG 0x3FF48018 R/W

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4.12 Register Summary 4 IO_MUX AND GPIO MATRIX

Name Description Address Access

RTCIO_RTC_GPIO_PIN15_REG RTC configuration for pin 15_REG 0x3FF48019 R/W

RTCIO_RTC_GPIO_PIN16_REG RTC configuration for pin 16_REG 0x3FF4801A R/W

RTCIO_RTC_GPIO_PIN17_REG RTC configuration for pin 17_REG 0x3FF4801B R/W

RTCIO_DIG_PAD_HOLD_REG RTC GPIO hold register_REG 0x3FF4801D R/W

GPIO RTC functions configuration registers

RTCIO_HALL_SENS_REG Hall sensor configuration_REG 0x3FF4801E R/W

RTCIO_SENSOR_PADS_REG Sensor pads configuration register_REG 0x3FF4801F R/W

RTCIO_ADC_PAD_REG ADC configuration register_REG 0x3FF48020 R/W

RTCIO_PAD_DAC1_REG DAC1 configuration register_REG 0x3FF48021 R/W

RTCIO_PAD_DAC2_REG DAC2 configuration register_REG 0x3FF48022 R/W

RTCIO_XTAL_32K_PAD_REG 32KHz crystal pads configuration register_REG 0x3FF48023 R/W

RTCIO_TOUCH_CFG_REG Touch sensor configuration register_REG 0x3FF48024 R/W

RTCIO_EXT_WAKEUP0_REG External wake up configuration register_REG 0x3FF4802F R/W

RTCIO_XTL_EXT_CTR_REG Crystal power down enable gpio source_REG 0x3FF48030 R/W

RTCIO_SAR_I2C_IO_REG RTC I2C pad selection_REG 0x3FF48031 R/W

Espressif Systems 44 ESP32 Technical Reference Manual V1.0

4.13 Registers 4 IO_MUX AND GPIO MATRIX

4.13 Registers

31 0

x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x

GPIO_OUT_REG GPIO0-31 output value. (R/W)

31 0

x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x

GPIO_OUT_W1TS_REG GPIO0-31 output set register. For every bit that is one in the value that is

written here, the corresponding bit in GPIO_OUT_DATA will be set. (RO)

Reset

31 0

x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x

GPIO_OUT_W1TC_REG GPIO0-31 output clear register. For every bit that is one in the value that is

written here, the corresponding bit in GPIO_OUT_DATA will be cleared. (RO)

(reserved)

31 8

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

7 0

x x x x x x x x

GPIO_OUT_DATA

GPIO_OUT_DATA GPIO32-39 output value. (R/W)

Reset

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4.13 Registers 4 IO_MUX AND GPIO MATRIX

(reserved)

31 8

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

7 0

x x x x x x x x

GPIO_OUT_DATA

GPIO_OUT_DATA GPIO32-39 output value set register. For every bit that is one in the value that is

written here, the corresponding bit in GPIO_OUT1_DATA will be set. (RO)

(reserved)

31 8

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

7 0

x x x x x x x x

GPIO_OUT_DATA

GPIO_OUT_DATA GPIO32-39 output value clear register. For every bit that is one in the value that is

written here, the corresponding bit in GPIO_OUT1_DATA will be cleared. (RO)

Reset

31 0

x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x

GPIO_ENABLE_REG GPIO0-31 output enable. (R/W)

31 0

x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x

GPIO_ENABLE_W1TS_REG GPIO0-31 output enable set register. For every bit that is one in the

value that is written here, the corresponding bit in GPIO_ENABLE will be set. (RO)

31 0

x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x

Reset

GPIO_ENABLE_W1TC_REG GPIO0-31 output enable clear register. For every bit that is one in the

value that is written here, the corresponding bit in GPIO_ENABLE will be cleared. (RO)

Espressif Systems 46 ESP32 Technical Reference Manual V1.0

4.13 Registers 4 IO_MUX AND GPIO MATRIX

(reserved)

31 8

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

7 0

x x x x x x x x

GPIO_ENABLE_DATA

GPIO_ENABLE_DATA GPIO32-39 output enable. (R/W)

(reserved)

31 8

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

7 0

x x x x x x x x

GPIO_ENABLE_DATA

GPIO_ENABLE_DATA GPIO32-39 output enable set register. For every bit that is one in the value

that is written here, the corresponding bit in GPIO_ENABLE1 will be set. (RO)

Reset

(reserved)

31 8

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

7 0

x x x x x x x x

GPIO_ENABLE_DATA

GPIO_ENABLE_DATA GPIO32-39 output enable clear register. For every bit that is one in the value

that is written here, the corresponding bit in GPIO_ENABLE1 will be cleared. (RO)

(reserved)

31 16

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

15 0

x x x x x x x x x x x x x x x x

GPIO_STRAPPING

Reset

GPIO_STRAPPING GPIO strapping results: boot_sel_chip[5:0]: MTDI, GPIO0, GPIO2, GPIO4,

MTDO, GPIO5.

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4.13 Registers 4 IO_MUX AND GPIO MATRIX

31 0

x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x

Reset

GPIO_IN_REG GPIO0-31 input value. Each bit represents pad input value, 1 for high level and 0 for

low level. (RO)

(reserved)

31 8

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

7 0

x x x x x x x x

GPIO_IN_DATA_NEXT

GPIO_IN_DATA_NEXT GPIO32-39 input value. Each bit represents pad input value. (RO)

31 0

x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x

GPIO_STATUS_REG GPIO0-31 interrupt status register. Each bit can be the two interrupt sources

for the two CPUs. The enable bits in GPIO_STATUS_INTERRUPT corresponding to the 0-4 bits in

GPIO_PINn_REG should be set to 1. (R/W)

31 0

x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x

Reset

GPIO_STATUS_W1TS_REG GPIO0-31 interrupt status set register. For every bit that is one in the

value that is written here, the corresponding bit in GPIO_STATUS_INTERRUPT will be set. (RO)

31 0

x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x

Reset

GPIO_STATUS_W1TC_REG GPIO0-31 interrupt status clear register. For every bit that is one in the

value that is written here, the corresponding bit in GPIO_STATUS_INTERRUPT will be cleared. (RO)

Espressif Systems 48 ESP32 Technical Reference Manual V1.0

4.13 Registers 4 IO_MUX AND GPIO MATRIX

(reserved)

31 8

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

7 0

x x x x x x x x

GPIO_STATUS_INTERRUPT

GPIO_STATUS_INTERRUPT GPIO32-39 interrupt status. (R/W)

(reserved)

31 8

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

7 0

x x x x x x x x

GPIO_STATUS_INTERRUPT

GPIO_STATUS_INTERRUPT GPIO32-39 interrupt status set register. For every bit that is one in the

value that is written here, the corresponding bit in GPIO_STATUS_INTERRUPT1 will be set. (RO)

Reset

(reserved)

31 8

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

7 0

x x x x x x x x

GPIO_STATUS_INTERRUPT

GPIO_STATUS_INTERRUPT GPIO32-39 interrupt status clear register. For every bit that is one in

the value that is written here, the corresponding bit in GPIO_STATUS_INTERRUPT1 will be cleared.

(RO)

31 0

x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x

Reset

GPIO_ACPU_INT_REG GPIO0-31 APP CPU interrupt status. (RO)

Espressif Systems 49 ESP32 Technical Reference Manual V1.0

4.13 Registers 4 IO_MUX AND GPIO MATRIX

31 0

x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x

Reset

GPIO_ACPU_NMI_INT_REG GPIO0-31 APP CPU non-maskable interrupt status. (RO)

31 0

x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x

Reset

GPIO_PCPU_INT_REG GPIO0-31 PRO CPU interrupt status. (RO)

31 0

x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x

GPIO_PCPU_NMI_INT_REG GPIO0-31 PRO CPU non-maskable interrupt status. (RO)

(reserved)

31 8

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

7 0

x x x x x x x x

GPIO_APPCPU_INT

GPIO_APPCPU_INT GPIO32-39 APP CPU interrupt status. (RO)

Reset

(reserved)

31 8

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

7 0

x x x x x x x x

GPIO_APPCPU_NMI_INT

Reset

GPIO_APPCPU_NMI_INT GPIO32-39 APP CPU non-maskable interrupt status. (RO)

Espressif Systems 50 ESP32 Technical Reference Manual V1.0

4.13 Registers 4 IO_MUX AND GPIO MATRIX

(reserved)

31 8

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

7 0

x x x x x x x x

GPIO_PROCPU_INT GPIO32-39 PRO CPU interrupt status. (RO)

(reserved)

31 8

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

7 0

x x x x x x x x

GPIO_PROCPU_NMI_INT GPIO32-39 PRO CPU non-maskable interrupt status. (RO)

GPIO_PROCPU_INT

Reset

GPIO_PROCPU_NMI_INT

Reset

Espressif Systems 51 ESP32 Technical Reference Manual V1.0

4.13 Registers 4 IO_MUX AND GPIO MATRIX

(reserved)

31 18

0 0 0 0 0 0 0 0 0 0 0 0 0 0

GPIO_PINn_INT_ENA

17 13

x x x x x

(reserved)

12 11

0 0

GPIO_PINn_WAKEUP_ENABLE

GPIO_PINn_INT_TYPE

9 7

x x x

(reserved)

6 3

0 0 0 0

GPIO_PINn_PAD_DRIVER

3 2

0 0

GPIO_PINn_INT_ENA Interrupt enable bits for pin n: (R/W)

bit0: APP CPU interrupt enable;

bit1: APP CPU non-maskable interrupt enable;

bit3: PRO CPU interrupt enable;

bit4: PRO CPU non-maskable interrupt enable.

GPIO_PINn_WAKEUP_ENABLE GPIO wake up enable. Will only wake the CPU from Light-sleep.

(R/W)

GPIO_PINn_INT_TYPE Interrupt type selection: (R/W)

0: GPIO interrupt disable;

1: rising edge trigger;

2: falling edge trigger;

3: any edge trigger;

4: low level trigger;

5: high level trigger.

(reserved)

Reset

GPIO_PINn_PAD_DRIVER 0: normal output; 1: open drain output. (R/W)

(reserved)

31 8

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

GPIO_FUNCm_IN_INV_SEL

GPIO_SIGm_IN_SEL

5 0

x x x x x x

GPIO_FUNCm_IN_SEL

GPIO_SIGm_IN_SEL Bypass the GPIO Matrix. 0: route through GPIO Matrix, 1: connect signal

directly to peripheral configured in the IO_MUX. (R/W)

GPIO_FUNCm_IN_INV_SEL Invert the input value. 1: invert; 0: do not invert. (R/W)

GPIO_FUNCm_IN_SEL Selection control for peripheral input m. A value of 0-39 selects which of the

40 GPIO Matrix input pins this signal is connected to, or 0x38 for a constant high input or 0x30 for

a constant low input. (R/W)

Reset

Espressif Systems 52 ESP32 Technical Reference Manual V1.0

4.13 Registers 4 IO_MUX AND GPIO MATRIX

(reserved)

31 12

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

GPIO_FUNCn_OUT_INV_SEL

GPIO_FUNCn_OEN_SEL

GPIO_FUNCn_OEN_INV_SEL

8 0

x x x x x x x x x

GPIO_FUNCn_OUT_SEL

GPIO_FUNCn_OEN_INV_SEL 1: Invert the output enable signal; 0: do not invert the output enable

signal. (R/W)

GPIO_FUNCn_OEN_SEL 1: Force the output enable signal to be sourced from bit n of

GPIO_ENABLE_REG; 0: use output enable signal from peripheral. (R/W)

GPIO_FUNCn_OUT_INV_SEL 1: Invert the output value; 0: do not invert the output value. (R/W)

GPIO_FUNCn_OUT_SEL Selection control for GPIO output n. A value of s(0<=s<256) connects

peripheral output s to GPIO output n. A value of 256 selects bit n of GPIO_DATA_REG and

GPIO_ENABLE_REG as the output value and output enable. (R/W)

Reset

Espressif Systems 53 ESP32 Technical Reference Manual V1.0

4.13 Registers 4 IO_MUX AND GPIO MATRIX

(reserved)

31 15

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

IO_x_MCU_SEL

14 12

0x0

IO_x_FUNC_DRV

11 10

0x2

IO_x_FUNC_IE

IO_x_FUNC_WPD

IO_x_FUNC_WPU

IO_x_MCU_DRV

6 5

0x0

IO_x_MCU_IE

IO_x_MCU_WPD

IO_x_MCU_WPU

IO_x_SLP_SEL

IO_x_MCU_SEL Select the IO_MUX function for this signal. 0 selects Function 1, 1 selects Function

2, etc. (R/W)

IO_x_FUNC_DRV Select the drive strength of the pad. A higher value selects a higher strength. (R/W)

IO_x_FUNC_IE Input enable of the pad. 1: input enabled; 0: input disabled. (R/W)

IO_x_FUNC_WPU Pull-up enable of the pad. 1: internal pull-up enabled; 0: internal pull-up disabled.

(R/W)

IO_x_FUNC_WPD Pull-down enable of the pad. 1: internal pull-down enabled, 0: internal pull-down

disabled. (R/W)

IO_x_MCU_DRV Select the drive strength of the pad during sleep mode. A higher value selects a

higher strength. (R/W)

IO_x_MCU_IE Input enable of the pad during sleep mode. 1: input enabled; 0: input disabled. (R/W)

IO_x_MCU_WPU Pull-up enable of the pad during sleep mode. 1: internal pull-up enabled; 0: internal

pull-up disabled. (R/W)

IO_x_MCU_OE

Reset

IO_x_MCU_WPD Pull-down enable of the pad during sleep mode. 1: internal pull-down enabled; 0:

internal pull-down disabled. (R/W)

IO_x_SLP_SEL Sleep mode selection of this pad. Set to 1 to put the pad in sleep mode. (R/W)

IO_x_MCU_OE Output enable of the pad in sleep mode. 1: enable output; 0: disable output. (R/W)

RTCIO_RTC_GPIO_OUT_DATA

31 14

x x x x x x x x x x x x x x x x x x

27 14

0 0 0 0 0 0 0 0 0 0 0 0 0 0

(reserved)

RTCIO_RTC_GPIO_OUT_DATA GPIO0-17 output register. Bit14 is GPIO[0], bit15 is GPIO[1], etc.

(R/W)

Reset

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4.13 Registers 4 IO_MUX AND GPIO MATRIX

RTCIO_RTC_GPIO_OUT_DATA_W1TS

31 14

x x x x x x x x x x x x x x x x x x

27 14

0 0 0 0 0 0 0 0 0 0 0 0 0 0

(reserved)

RTCIO_RTC_GPIO_OUT_DATA_W1TS GPIO0-17 output set register. For every bit that is one in the

value that is written here, the corresponding bit in RTCIO_RTC_GPIO_OUT will be set. (WO)

RTCIO_RTC_GPIO_OUT_DATA_W1TC

31 14

x x x x x x x x x x x x x x x x x x

27 14

0 0 0 0 0 0 0 0 0 0 0 0 0 0

(reserved)

Reset

RTCIO_RTC_GPIO_OUT_DATA_W1TC GPIO0-17 output clear register. For every bit that is one in

the value that is written here, the corresponding bit in RTCIO_RTC_GPIO_OUT will be cleared.

(WO)

RTCIO_RTC_GPIO_ENABLE

31 14

x x x x x x x x x x x x x x x x x x

27 14

0 0 0 0 0 0 0 0 0 0 0 0 0 0

(reserved)

RTCIO_RTC_GPIO_ENABLE GPIO0-17 output enable. Bit14 is GPIO[0], bit15 is GPIO[1], etc. 1

means this GPIO pad is output. (R/W)

Reset

Espressif Systems 55 ESP32 Technical Reference Manual V1.0

4.13 Registers 4 IO_MUX AND GPIO MATRIX

RTCIO_RTC_GPIO_ENABLE_W1TS

31 14

x x x x x x x x x x x x x x x x x x

27 14

0 0 0 0 0 0 0 0 0 0 0 0 0 0

(reserved)

RTCIO_RTC_GPIO_ENABLE_W1TS GPIO0-17 output enable set register. For every bit that is one

in the value that is written here, the corresponding bit in RTCIO_RTC_GPIO_ENABLE will be set.

(WO)

RTCIO_RTC_GPIO_ENABLE_W1TC

31 14

x x x x x x x x x x x x x x x x x x

27 14

0 0 0 0 0 0 0 0 0 0 0 0 0 0

(reserved)

Reset

RTCIO_RTC_GPIO_ENABLE_W1TC GPIO0-17 output enable clear register. For every bit that is

one in the value that is written here, the corresponding bit in RTCIO_RTC_GPIO_ENABLE will be

cleared. (WO)

RTCIO_RTC_GPIO_STATUS_INT

31 14

x x x x x x x x x x x x x x x x x x

27 14

0 0 0 0 0 0 0 0 0 0 0 0 0 0

(reserved)

RTCIO_RTC_GPIO_STATUS_INT GPIO0-17 interrupt status. Bit14 is GPIO[0], bit15 is GPIO[1],

etc. This register should be used together with RTCIO_RTC_GPIO_PINn_INT_TYPE in RT-

CIO_RTC_GPIO_PINn_REG. 1 means there is corresponding interrupt, 0 means there is no in-

terrupt. (R/W)

Reset

Espressif Systems 56 ESP32 Technical Reference Manual V1.0

4.13 Registers 4 IO_MUX AND GPIO MATRIX

RTCIO_RTC_GPIO_STATUS_INT_W1TS

31 14

x x x x x x x x x x x x x x x x x x

27 14

0 0 0 0 0 0 0 0 0 0 0 0 0 0

(reserved)

RTCIO_RTC_GPIO_STATUS_INT_W1TS GPIO0-17 interrupt set register. For every bit that is one in

the value that is written here, the corresponding bit in RTCIO_RTC_GPIO_STATUS_INT will be set.

(WO)

RTCIO_RTC_GPIO_STATUS_INT_W1TC

31 14

x x x x x x x x x x x x x x x x x x

27 14

0 0 0 0 0 0 0 0 0 0 0 0 0 0

(reserved)

Reset

RTCIO_RTC_GPIO_STATUS_INT_W1TC GPIO0-17 interrupt clear register. For every bit that is one

in the value that is written here, the corresponding bit in RTCIO_RTC_GPIO_STATUS_INT will be

cleared. (WO)

RTCIO_RTC_GPIO_IN_NEXT

31 14

x x x x x x x x x x x x x x x x x x

27 14

0 0 0 0 0 0 0 0 0 0 0 0 0 0

(reserved)

RTCIO_RTC_GPIO_IN_NEXT GPIO0-17 input value. Bit14 is GPIO[0], bit15 is GPIO[1], etc. Each

bit represents pad input value, 1 for high level and 0 for low level. (RO)

Reset

Espressif Systems 57 ESP32 Technical Reference Manual V1.0

4.13 Registers 4 IO_MUX AND GPIO MATRIX

(reserved)

31 11

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

RTCIO_RTC_GPIO_PINn_WAKEUP_ENABLE

RTCIO_RTC_GPIO_PINn_INT_TYPE

9 7

x x x

(reserved)

6 3

0 0 0 0

RTCIO_RTC_GPIO_PINn_PAD_DRIVER

3 2

0 0

RTCIO_RTC_GPIO_PINn_WAKEUP_ENABLE GPIO wake up enable. This will only wake up the

ESP32 from Light-sleep. (R/W)

RTCIO_RTC_GPIO_PINn_INT_TYPE GPIO interrupt type selection. (R/W)

0: GPIO interrupt disable;

1: rising edge trigger;

2: falling edge trigger;

3: any edge trigger;

4: low level trigger;

5: high level trigger.

RTCIO_RTC_GPIO_PINn_PAD_DRIVER Pad driver selection. 0: normal output; 1: open drain.

(R/W)

(reserved)

Reset

31 0

RTCIO_DIG_PAD_HOLD_REG Select which digital pads are on hold. 0 allows normal operation, 1

holds the pad. (R/W)

RTCIO_HALL_PHASE

RTCIO_HALL_XPD_HALL

59 30

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

(reserved)

RTCIO_HALL_XPD_HALL Power on hall sensor and connect to VP and VN. (R/W)

RTCIO_HALL_PHASE Reverse the polarity of the hall sensor. (R/W)

Reset

Espressif Systems 58 ESP32 Technical Reference Manual V1.0

4.13 Registers 4 IO_MUX AND GPIO MATRIX

RTCIO_SENSOR_SENSE4_MUX_SEL

RTCIO_SENSOR_SENSE3_MUX_SEL

RTCIO_SENSOR_SENSE2_MUX_SEL

RTCIO_SENSOR_SENSE1_MUX_SEL

RTCIO_SENSOR_SENSE4_HOLD

RTCIO_SENSOR_SENSE3_HOLD

RTCIO_SENSOR_SENSE2_HOLD

RTCIO_SENSOR_SENSE1_HOLD

RTCIO_SENSOR_SENSE2_FUN_SEL

RTCIO_SENSOR_SENSE1_FUN_SEL

23 22

RTCIO_SENSOR_SENSE1_FUN_IE

RTCIO_SENSOR_SENSE1_SLP_IE

RTCIO_SENSOR_SENSE1_SLP_SEL

18 17

RTCIO_SENSOR_SENSE2_SLP_SEL

RTCIO_SENSOR_SENSE3_FUN_IE

RTCIO_SENSOR_SENSE2_FUN_IE

RTCIO_SENSOR_SENSE2_SLP_IE

RTCIO_SENSOR_SENSE3_FUN_SEL

13 12

RTCIO_SENSOR_SENSE3_SLP_IE

RTCIO_SENSOR_SENSE3_SLP_SEL

RTCIO_SENSOR_SENSE4_FUN_SEL

8 7

RTCIO_SENSOR_SENSE4_FUN_IE

RTCIO_SENSOR_SENSE4_SLP_IE

RTCIO_SENSOR_SENSE4_SLP_SEL

(reserved)

7 4

0 0 0 0

RTCIO_SENSOR_SENSEn_HOLD Set to 1 to hold the output value on sensen, 0 for normal opera-

tion. (R/W)

RTCIO_SENSOR_SENSEn_MUX_SEL 1: route sensen to the RTC block; 0: route sensen to the

digital IO_MUX. (R/W)

RTCIO_SENSOR_SENSEn_FUN_SEL Select the RTC IO_MUX function for this pad. 0: select Func-

tion 0; 1: select Function 1. (R/W)

RTCIO_SENSOR_SENSEn_SLP_SEL Sleep mode selection signal of the pad. Set to 1 to put the

pad in sleep mode. (R/W)

RTCIO_SENSOR_SENSEn_SLP_IE Input enable of the pad in sleep mode. 1: enabled; 0: disabled.

(R/W)

RTCIO_SENSOR_SENSEn_FUN_IE Input enable of the pad. 1: enabled; 0: disabled. (R/W)

Reset

Espressif Systems 59 ESP32 Technical Reference Manual V1.0

4.13 Registers 4 IO_MUX AND GPIO MATRIX

RTCIO_ADC_ADC1_HOLD

RTCIO_ADC_ADC1_FUN_SEL

27 26

RTCIO_ADC_ADC2_MUX_SEL

RTCIO_ADC_ADC1_MUX_SEL

RTCIO_ADC_ADC2_HOLD

RTCIO_ADC_ADC1_FUN_IE

RTCIO_ADC_ADC1_SLP_IE

RTCIO_ADC_ADC1_SLP_SEL

RTCIO_ADC_ADC2_FUN_SEL

22 21

RTCIO_ADC_ADC2_SLP_IE

RTCIO_ADC_ADC2_SLP_SEL

RTCIO_ADC_ADC2_FUN_IE

35 18

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

(reserved)

RTCIO_ADC_ADCn_HOLD Set to 1 to hold the output value on the pad, 0 for normal operation.

(R/W)

RTCIO_ADC_ADCn_MUX_SEL 1: route pad to the digital IO_MUX; (R/W)

0: route pad to the RTC block.

RTCIO_ADC_ADCn_FUN_SEL Select the RTC function for this pad. 0: select Function 0; 1: select

Function 1. (R/W)

RTCIO_ADC_ADCn_SLP_SEL Sleep mode selection signal of the pad. Set this bit to 1 to put the

pad to sleep. (R/W)

RTCIO_ADC_ADCn_SLP_IE Input enable of the pad in sleep mode. 1: enabled; 0: disabled. (R/W)

RTCIO_ADC_ADCn_FUN_IE Input enable of the pad. 1: enabled; 0: disabled. (R/W)

Reset

Espressif Systems 60 ESP32 Technical Reference Manual V1.0

4.13 Registers 4 IO_MUX AND GPIO MATRIX

RTCIO_PAD_PDAC1_RDE

RTCIO_PAD_PDAC1_HOLD

RTCIO_PAD_PDAC1_DRV

31 30

RTCIO_PAD_PDAC1_RUE

26 19

RTCIO_PAD_PDAC1_DAC

RTCIO_PAD_PDAC1_XPD_DAC

RTCIO_PAD_PDAC1_FUN_SEL

RTCIO_PAD_PDAC1_MUX_SEL

16 15

RTCIO_PAD_PDAC1_SLP_IE

RTCIO_PAD_PDAC1_SLP_OE

RTCIO_PAD_PDAC1_SLP_SEL

RTCIO_PAD_PDAC1_DAC_XPD_FORCE

RTCIO_PAD_PDAC1_FUN_IE

19 10

0 0 0 0 0 0 0 0 0 0

(reserved)

RTCIO_PAD_PDAC1_DRV Select the drive strength of the pad. (R/W)

RTCIO_PAD_PDAC1_HOLD Set to 1 to hold the output value on the pad, 0 for normal operation.

(R/W)

RTCIO_PAD_PDAC1_RDE 1: Pull-down on pad enabled; 0: Pull-down disabled. (R/W)

RTCIO_PAD_PDAC1_RUE 1: Pull-up on pad enabled; 0: Pull-up disabled. (R/W)

RTCIO_PAD_PDAC1_DAC PAD DAC1 output value. (R/W)

RTCIO_PAD_PDAC1_XPD_DAC Power on DAC1. Usually, PDAC1 needs to be tristated if we power

on the DAC, i.e. IE=0, OE=0, RDE=0, RUE=0. (R/W)

RTCIO_PAD_PDAC1_MUX_SEL 1: route pad to the digital IO_MUX; (R/W)

0: route sense 4 to the RTC block.

RTCIO_PAD_PDAC1_FUN_SEL the functional selection signal of the pad. (R/W)

RTCIO_PAD_PDAC1_SLP_SEL Sleep mode selection signal of the pad. Set this bit to 1 to put the

pad to sleep. (R/W)

Reset

RTCIO_PAD_PDAC1_SLP_IE Input enable of the pad in sleep mode. 1: enabled; 0: disabled. (R/W)

RTCIO_PAD_PDAC1_SLP_OE Output enable of the pad. 1: enabled; 0: disabled. (R/W)

RTCIO_PAD_PDAC1_FUN_IE Input enable of the pad. 1: enabled; 0: disabled. (R/W)

RTCIO_PAD_PDAC1_DAC_XPD_FORCE Power on DAC1. Usually, we need to tristate PDAC1 if

we power on the DAC, i.e. IE=0, OE=0, RDE=0, RUE=0. (R/W)

Espressif Systems 61 ESP32 Technical Reference Manual V1.0

4.13 Registers 4 IO_MUX AND GPIO MATRIX

RTCIO_PAD_PDAC2_RDE

RTCIO_PAD_PDAC2_HOLD

RTCIO_PAD_PDAC2_DRV

31 30

RTCIO_PAD_PDAC2_RUE

26 19

RTCIO_PAD_PDAC2_DAC

RTCIO_PAD_PDAC2_XPD_DAC

RTCIO_PAD_PDAC2_FUN_SEL

RTCIO_PAD_PDAC2_MUX_SEL

16 15

RTCIO_PAD_PDAC2_SLP_IE

RTCIO_PAD_PDAC2_SLP_OE

RTCIO_PAD_PDAC2_SLP_SEL

RTCIO_PAD_PDAC2_DAC_XPD_FORCE

RTCIO_PAD_PDAC2_FUN_IE

19 10

0 0 0 0 0 0 0 0 0 0

(reserved)

RTCIO_PAD_PDAC2_DRV Select the drive strength of the pad. (R/W)

RTCIO_PAD_PDAC2_HOLD Set to 1 to hold the output value on the pad, 0 for normal operation.

(R/W)

RTCIO_PAD_PDAC2_RDE 1: Pull-down on pad enabled; 0: Pull-down disabled. (R/W)

RTCIO_PAD_PDAC2_RUE 1: Pull-up on pad enabled; 0: Pull-up disabled. (R/W)

RTCIO_PAD_PDAC2_DAC PAD DAC2 output value. (R/W)

RTCIO_PAD_PDAC2_XPD_DAC Power on DAC2. PDAC2 needs to be tristated if we power on the

DAC, i.e. IE=0, OE=0, RDE=0, RUE=0. (R/W)

RTCIO_PAD_PDAC2_MUX_SEL 1: route pad to the digital IO_MUX; (R/W)

0: route sense 4 to the RTC block.

RTCIO_PAD_PDAC2_FUN_SEL Select the RTC function for this pad. 0: select Function 0; 1: select

Function 1. (R/W)

Reset

RTCIO_PAD_PDAC2_SLP_SEL Sleep mode selection signal of the pad. Set this bit to 1 to put the

pad to sleep. (R/W)

RTCIO_PAD_PDAC2_SLP_IE Input enable of the pad in sleep mode. 1: enabled; 0: disabled. (R/W)

RTCIO_PAD_PDAC2_SLP_OE Output enable of the pad. 1: enabled; 0: disabled. (R/W)

RTCIO_PAD_PDAC2_FUN_IE Input enable of the pad. 1: enabled; 0: disabled. (R/W)

RTCIO_PAD_PDAC2_DAC_XPD_FORCE Power on DAC2. Usually, we need to tristate PDAC2 if

we power on the DAC, i.e. IE=0, OE=0, RDE=0, RUE=0. (R/W)

Espressif Systems 62 ESP32 Technical Reference Manual V1.0

4.13 Registers 4 IO_MUX AND GPIO MATRIX

RTCIO_XTAL_X32N_DRV

RTCIO_XTAL_X32N_HOLD

31 30

RTCIO_XTAL_X32P_DRV

RTCIO_XTAL_X32N_RUE

RTCIO_XTAL_X32N_RDE

26 25

RTCIO_XTAL_X32P_RDE

RTCIO_XTAL_X32P_HOLD

RTCIO_XTAL_DAC_XTAL_32K

RTCIO_XTAL_X32P_RUE

21 20

0 1

RTCIO_XTAL_X32N_MUX_SEL

RTCIO_XTAL_XPD_XTAL_32K

RTCIO_XTAL_X32N_FUN_SEL

RTCIO_XTAL_X32P_MUX_SEL

16 15

RTCIO_XTAL_X32N_SLP_IE

RTCIO_XTAL_X32N_SLP_SEL

RTCIO_XTAL_X32N_FUN_IE

RTCIO_XTAL_X32N_SLP_OE

RTCIO_XTAL_X32P_FUN_SEL

RTCIO_XTAL_X32P_SLP_SEL

10 9

RTCIO_XTAL_X32P_FUN_IE

RTCIO_XTAL_X32P_SLP_OE

RTCIO_XTAL_X32P_SLP_IE

RTCIO_XTAL_DRES_XTAL_32K

4 3

2 1

1 0

0 0

(reserved)

RTCIO_XTAL_DBIAS_XTAL_32K

Reset

RTCIO_XTAL_X32N_DRV Select the drive strength of the pad. (R/W)

RTCIO_XTAL_X32N_HOLD Set to 1 to hold the output value on the pad, 0 for normal operation. (R/W)

RTCIO_XTAL_X32N_RDE 1: Pull-down on pad enabled; 0: Pull-down disabled. (R/W)

RTCIO_XTAL_X32N_RUE 1: Pull-up on pad enabled; 0: Pull-up disabled. (R/W)

RTCIO_XTAL_X32P_DRV Select the drive strength of the pad. (R/W)

RTCIO_XTAL_X32P_HOLD Set to 1 to hold the output value on the pad, 0 for normal operation. (R/W)

RTCIO_XTAL_X32P_RDE 1: Pull-down on pad enabled; 0: Pull-down disabled. (R/W)

RTCIO_XTAL_X32P_RUE 1: Pull-up on pad enabled; 0: Pull-up disabled. (R/W)

RTCIO_XTAL_DAC_XTAL_32K 32K XTAL bias current DAC value. (R/W)

RTCIO_XTAL_XPD_XTAL_32K Power up 32 KHz crystal oscillator. (R/W)

RTCIO_XTAL_X32N_MUX_SEL 1: route X32N pad to the digital IO_MUX, 0: route to RTC block. (R/W)

RTCIO_XTAL_X32P_MUX_SEL 1: route X32P pad to the digital IO_MUX, 0: route to RTC block. (R/W)

RTCIO_XTAL_X32N_FUN_SEL Select the RTC function. 0: select function0; 1: select function1. (R/W)

RTCIO_XTAL_X32N_SLP_SEL Sleep mode selection. Set this bit to 1 to put the pad to sleep. (R/W)

RTCIO_XTAL_X32N_SLP_IE Input enable of the pad in sleep mode. 1: enabled; 0: disabled. (R/W)

RTCIO_XTAL_X32N_SLP_OE Output enable of the pad. 1: enabled; 0: disabled. (R/W)

RTCIO_XTAL_X32N_FUN_IE Input enable of the pad. 1: enabled; 0: disabled. (R/W)

RTCIO_XTAL_X32P_FUN_SEL Select the RTC function. 0: select Function 0; 1: select Function 1. (R/W)

RTCIO_XTAL_X32P_SLP_SEL Sleep mode selection. Set this bit to 1 to put the pad to sleep. (R/W)

RTCIO_XTAL_X32P_SLP_IE Input enable of the pad in sleep mode. 1: enabled; 0: disabled. (R/W)

RTCIO_XTAL_X32P_SLP_OE Output enable of the pad in sleep mode. 1: enabled; 0: disabled. (R/W)

RTCIO_XTAL_X32P_FUN_IE Input enable of the pad. 1: enabled; 0: disabled. (R/W)

RTCIO_XTAL_DRES_XTAL_32K 32K XTAL resistor bias control. (R/W)

RTCIO_XTAL_DBIAS_XTAL_32K 32K XTAL self-bias reference control. (R/W)

Espressif Systems 63 ESP32 Technical Reference Manual V1.0

4.13 Registers 4 IO_MUX AND GPIO MATRIX

RTCIO_TOUCH_DREFH

RTCIO_TOUCH_XPD_BIAS

30 29

28 27

1 1

0 0

RTCIO_TOUCH_DRANGE

RTCIO_TOUCH_DREFL

26 25

1 1

RTCIO_TOUCH_DCUR

24 23

45 23

0 0

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

(reserved)

RTCIO_TOUCH_XPD_BIAS Touch sensor bias power on bit. 1: power on; 0: disabled. (R/W)

RTCIO_TOUCH_DREFH Touch sensor saw wave top voltage. (R/W)

RTCIO_TOUCH_DREFL Touch sensor saw wave bottom voltage. (R/W)

RTCIO_TOUCH_DRANGE Touch sensor saw wave voltage range. (R/W)

RTCIO_TOUCH_DCUR Touch sensor bias current. When BIAS_SLEEP is enabled, this setting is

available. (R/W)

Reset

(reserved)

31 26

0 0 0 0 0 0

RTCIO_TOUCH_PADn_DAC

RTCIO_TOUCH_PADn_START

25 23

0x4

RTCIO_TOUCH_PADn_TO_GPIO

RTCIO_TOUCH_PADn_XPD

RTCIO_TOUCH_PADn_TIE_OPT

37 19

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

(reserved)

RTCIO_TOUCH_PADn_DAC Touch sensor slope control. 3-bit for each touch pad, defaults to 100.

(R/W)

RTCIO_TOUCH_PADn_START Start touch sensor. (R/W)

RTCIO_TOUCH_PADn_TIE_OPT Default touch sensor tie option. 0: tie low; 1: tie high. (R/W)

RTCIO_TOUCH_PADn_XPD Touch sensor power on. (R/W)

RTCIO_TOUCH_PADn_TO_GPIO Connect the RTC pad input to digital pad input, 0 is available.

(R/W)

Reset

Espressif Systems 64 ESP32 Technical Reference Manual V1.0

4.13 Registers 4 IO_MUX AND GPIO MATRIX

RTCIO_EXT_WAKEUP0_SEL

31 27

53 27

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

(reserved)

RTCIO_EXT_WAKEUP0_SEL GPIO[0-17] can be used to wake up the chip when the chip is in sleep

mode. This register selects the pad source to wake up the chip in deep/light sleep mode. 0: select

GPIO0; 1: select GPIO2, etc. (R/W)

RTCIO_XTL_EXT_CTR_SEL

31 27

53 27

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

(reserved)

RTCIO_XTL_EXT_CTR_SEL Select the external crystal power down enable source in sleep

mode. 0: select GPIO0; 1: select GPIO2, etc. The input value on this pin XOR RT-

CIO_RTC_EXT_XTAL_CONF_REG[30] is the crystal power down enable signal. (R/W)

Reset

RTCIO_SAR_I2C_SDA_SEL

RTCIO_SAR_I2C_SCL_SEL

31 30

29 28

55 28

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

(reserved)

RTCIO_SAR_I2C_SDA_SEL Selects a different pad as the RTC I2C SDA signal. 0: use pad

TOUCH_PAD[1]; 1: use pad TOUCH_PAD[3]. (R/W)

RTCIO_SAR_I2C_SCL_SEL Selects a different pad as the RTC I2C SCL signal. 0: use pad

TOUCH_PAD[1]; 1: use pad TOUCH_PAD[3]. (R/W)

Reset

Espressif Systems 65 ESP32 Technical Reference Manual V1.0

5 LED_PWM

5. LED_PWM

5.1 Introduction

The LED_PWM controller is primarily designed to control the intensity of LEDs, although it can be used to

generate PWM signals for other purposes as well. It has 16 channels which can generate independent

waveforms that can be used to drive e.g. RGB LED devices. For maximum flexibility, the high-speed as well as

the low-speed channels can be driven from one of four high-speed/low-speed timers. The PWM controller also

has the ability to automatically increase or decrease the duty cycle gradually, allowing for fades without any

processor interference. To increase resolution, the LED_PWM controller is also able to dither between two values

when a fractional PWM value is configured.

The LED_PWM controller has eight high-speed and eight low-speed PWM generators. In this document, they will

be referred to as hschn and lschn respectively. These channels can be driven from four timers, which will be

indicated by h_timerx and l_timerx.

5.2 Functional Description

5.2.1 Architecture

Figure 10: LED_PWM Architecture

Figure 10 shows the architecture of the LED_PWM controller. As can be seen from the figure, the LED_PWM

controller contains 8 high-speed and 8 low-speed channels. There are 4 high-speed clock modules for the

high-speed channels, from which one h_timerx can be selected. There are also 4 low-speed clock modules for

the low-speed channels, from which one l_timerx can be selected.

Figure 11: LED_PWM High-speed Channel Diagram

Espressif Systems 66 ESP32 Technical Reference Manual V1.0

5.2 Functional Description 5 LED_PWM

Figure 11 illustrates a PWM channel with its selected timer; in this instance a high-speed channel and associated

high-speed timer.

5.2.2 Timers

A high-speed timer consists of a multiplexer to select one of two clock sources: either REF_TICK or APB_CLK.

For more information on the clock sources, please refer to Chapter Reset And Clock. The input clock is divided

down by a divider first. The division factor is specified by LEDC_DIV_NUM_HSTIMERx which contains a fixed

point number: the highest 10 bits represent the integer portion while the lowest 8 bits contain the fractional

portion.

The divided clock signal is then fed into a 20-bit counter. This counter will count up to the value specified in

LEDC_HSTIMERx_LIM. An overflow interrupt will be generated once the counting value reaches this value, at

which point the counter restarts counting from 0. It is also possible to reset, suspend and read the values of the

counter by software.

The output signal of the timer is the 20-bit value generated by the counter. The cycle period of this signal defines

the frequency of the signals of any PWM channels connected to this timer. This frequency depends on both the

division factor of the divider as well as the range of the counter:

sig_out

REF_TICK

· (!LEDC_TICK_SEL_HSTIMERx) + f LEDC_DIV_NUM_HSTIMERx · 2

APB_CLK

· LEDC_TICK_SEL_HSTIMERx

LEDC_HSTIMERx_LIM

The low-speed timers l_timerx on the low-speed channel differ from the high-speed timers h_timerx in two

aspects:

1. Where the high-speed timer clock source can be clocked from REF_TICK or APB_CLK, the low speed

timers are sourced from either REF_TICK or SLOW_CLOCK. The SLOW_CLOCK source can be either

APB_CLK (80 MHz) or 8 MHz, selectable using LEDC_APB_CLK_SEL.

2. The high-speed counter and divider are glitch-free, meaning that if software modifies the maximum counter

or divisor value, the update will come into effect after the next overflow interrupt. In contrast, the low-speed

counter and divider will update these values only when LEDC_LSTIMERx_PARA_UP is set.

5.2.3 Channels

A channel takes the 20-bit value from the counter of the selected high-speed timer and compares it to a set of

two values in order to set the channel output. The first value it is compared to is the contents of

LEDC_HPOINT_HSCHn; if these two match, the output will be latched high. The second value is the sum of

LEDC_HPOINT_HSCHn and LEDC_DUTY_HSCHn[24..4]. When this value is reached, the output is latched low.

By using these two values, the relative phase and the duty cycle of the PWM output can be set. Figure 12

illustrates this.

Figure 12: LED PWM Output Signal Diagram

Espressif Systems 67 ESP32 Technical Reference Manual V1.0

5.3 Register Summary 5 LED_PWM

LEDC_DUTY_HSCHn is a fixed-point register with 4 fractional bits. As stated before, LEDC_DUTY_HSCHn[24..4]

is used in the PWM calculation directly, LEDC_DUTY_HSCHn[3..0] can be used to dither the output. If this value

is non-zero, with a statistical chance of LEDC_DUTY_HSCHn[3..0]/16, the actual PWM pulse will be one cycle

longer. This effectively increases the resolution of the PWM generator to 24 bits, but at the cost of a slight jitter in

the duty cycle.

The channels also have ability to automatically fade from one duty cycle value to another. This feature is enabled

by setting LEDC_DUTY_START_HSCHn. When this bit is set, the PWM controller will automatically increment or

decrement the value in LEDC_DUTY_HSCHn, depending on whether the bit LEDC_DUTY_INC_HSCHn is set or

cleared, respectively. The speed the duty cycle changes is defined as such: every LEDC_DUTY_CYCLE_HSCHn

cycles, the content of LEDC_DUTY_SCALE_HSCHn is added to or subtracted from LEDC_DUTY_HSCHn[24..4].

The length of the fade can be limited by setting LEDC_DUTY_NUM_HSCHn: the fade will only last that number of

cycles before finishing. A finished fade also generates an interrupt.

Figure 13: Output Signal Diagram of Gradient Duty Cycle

Figure 13 is an illustration of this. In this configuration, LEDC_DUTY_NUM_HSCHn_R increases by

LEDC_DUTY_SCALE_HSCHn every LEDC_DUTY_CYCLE_HSCHn clock cycles, which is reflected in the duty

cycle of the output signal.

5.2.4 Interrupts

• LEDC_DUTY_CHNG_END_LSCHn_INT: Triggered when a fade on a low-speed channel has finished.

• LEDC_DUTY_CHNG_END_HSCHn_INT: Triggered when a fade on a high-speed channel has finished.

• LEDC_HS_TIMERx_OVF_INT: Triggered when a high-speed timer has reached its maximum counter value.

• LEDC_LS_TIMERx_OVF_INT: Triggered when a low-speed timer has reached its maximum counter value.

5.3 Register Summary

Name Description Address Access

Configuration registers

LEDC_CONF_REG Global ledc configuration register 0x3FF59190 R/W

LEDC_HSCH0_CONF0_REG Configuration register 0 for high-speed channel 0 0x3FF59000 R/W

LEDC_HSCH1_CONF0_REG Configuration register 0 for high-speed channel 1 0x3FF59014 R/W

LEDC_HSCH2_CONF0_REG Configuration register 0 for high-speed channel 2 0x3FF59028 R/W

LEDC_HSCH3_CONF0_REG Configuration register 0 for high-speed channel 3 0x3FF5903C R/W

LEDC_HSCH4_CONF0_REG Configuration register 0 for high-speed channel 4 0x3FF59050 R/W

LEDC_HSCH5_CONF0_REG Configuration register 0 for high-speed channel 5 0x3FF59064 R/W

LEDC_HSCH6_CONF0_REG Configuration register 0 for high-speed channel 6 0x3FF59078 R/W

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5.3 Register Summary 5 LED_PWM

Name Description Address Access

LEDC_HSCH7_CONF0_REG Configuration register 0 for high-speed channel 7 0x3FF5908C R/W

LEDC_HSCH0_CONF1_REG Configuration register 1 for high-speed channel 0 0x3FF5900C R/W

LEDC_HSCH1_CONF1_REG Configuration register 1 for high-speed channel 1 0x3FF59020 R/W

LEDC_HSCH2_CONF1_REG Configuration register 1 for high-speed channel 2 0x3FF59034 R/W

LEDC_HSCH3_CONF1_REG Configuration register 1 for high-speed channel 3 0x3FF59048 R/W

LEDC_HSCH4_CONF1_REG Configuration register 1 for high-speed channel 4 0x3FF5905C R/W

LEDC_HSCH5_CONF1_REG Configuration register 1 for high-speed channel 5 0x3FF59070 R/W

LEDC_HSCH6_CONF1_REG Configuration register 1 for high-speed channel 6 0x3FF59084 R/W

LEDC_HSCH7_CONF1_REG Configuration register 1 for high-speed channel 7 0x3FF59098 R/W

LEDC_LSCH0_CONF0_REG Configuration register 0 for low-speed channel 0 0x3FF590A0 R/W

LEDC_LSCH1_CONF0_REG Configuration register 0 for low-speed channel 1 0x3FF590B4 R/W

LEDC_LSCH2_CONF0_REG Configuration register 0 for low-speed channel 2 0x3FF590C8 R/W

LEDC_LSCH3_CONF0_REG Configuration register 0 for low-speed channel 3 0x3FF590DC R/W

LEDC_LSCH4_CONF0_REG Configuration register 0 for low-speed channel 4 0x3FF590F0 R/W

LEDC_LSCH5_CONF0_REG Configuration register 0 for low-speed channel 5 0x3FF59104 R/W

LEDC_LSCH6_CONF0_REG Configuration register 0 for low-speed channel 6 0x3FF59118 R/W

LEDC_LSCH7_CONF0_REG Configuration register 0 for low-speed channel 7 0x3FF5912C R/W

LEDC_LSCH0_CONF1_REG Configuration register 1 for low-speed channel 0 0x3FF590AC R/W

LEDC_LSCH1_CONF1_REG Configuration register 1 for low-speed channel 1 0x3FF590C0 R/W

LEDC_LSCH2_CONF1_REG Configuration register 1 for low-speed channel 2 0x3FF590D4 R/W

LEDC_LSCH3_CONF1_REG Configuration register 1 for low-speed channel 3 0x3FF590E8 R/W

LEDC_LSCH4_CONF1_REG Configuration register 1 for low-speed channel 4 0x3FF590FC R/W

LEDC_LSCH5_CONF1_REG Configuration register 1 for low-speed channel 5 0x3FF59110 R/W

LEDC_LSCH6_CONF1_REG Configuration register 1 for low-speed channel 6 0x3FF59124 R/W

LEDC_LSCH7_CONF1_REG Configuration register 1 for low-speed channel 7 0x3FF59138 R/W

Duty-cycle registers

LEDC_HSCH0_DUTY_REG Initial duty cycle for high-speed channel 0 0x3FF59008 R/W

LEDC_HSCH1_DUTY_REG Initial duty cycle for high-speed channel 1 0x3FF5901C R/W

LEDC_HSCH2_DUTY_REG Initial duty cycle for high-speed channel 2 0x3FF59030 R/W

LEDC_HSCH3_DUTY_REG Initial duty cycle for high-speed channel 3 0x3FF59044 R/W

LEDC_HSCH4_DUTY_REG Initial duty cycle for high-speed channel 4 0x3FF59058 R/W

LEDC_HSCH5_DUTY_REG Initial duty cycle for high-speed channel 5 0x3FF5906C R/W

LEDC_HSCH6_DUTY_REG Initial duty cycle for high-speed channel 6 0x3FF59080 R/W

LEDC_HSCH7_DUTY_REG Initial duty cycle for high-speed channel 7 0x3FF59094 R/W

LEDC_HSCH0_DUTY_R_REG Current duty cycle for high-speed channel 0 0x3FF59010 RO

LEDC_HSCH1_DUTY_R_REG Current duty cycle for high-speed channel 1 0x3FF59024 RO

LEDC_HSCH2_DUTY_R_REG Current duty cycle for high-speed channel 2 0x3FF59038 RO

LEDC_HSCH3_DUTY_R_REG Current duty cycle for high-speed channel 3 0x3FF5904C RO

LEDC_HSCH4_DUTY_R_REG Current duty cycle for high-speed channel 4 0x3FF59060 RO

LEDC_HSCH5_DUTY_R_REG Current duty cycle for high-speed channel 5 0x3FF59074 RO

LEDC_HSCH6_DUTY_R_REG Current duty cycle for high-speed channel 6 0x3FF59088 RO

LEDC_HSCH7_DUTY_R_REG Current duty cycle for high-speed channel 7 0x3FF5909C RO

LEDC_LSCH0_DUTY_REG Initial duty cycle for low-speed channel 0 0x3FF590A8 R/W

LEDC_LSCH1_DUTY_REG Initial duty cycle for low-speed channel 1 0x3FF590BC R/W

Espressif Systems 69 ESP32 Technical Reference Manual V1.0

5.3 Register Summary 5 LED_PWM

Name Description Address Access

LEDC_LSCH2_DUTY_REG Initial duty cycle for low-speed channel 2 0x3FF590D0 R/W

LEDC_LSCH3_DUTY_REG Initial duty cycle for low-speed channel 3 0x3FF590E4 R/W

LEDC_LSCH4_DUTY_REG Initial duty cycle for low-speed channel 4 0x3FF590F8 R/W

LEDC_LSCH5_DUTY_REG Initial duty cycle for low-speed channel 5 0x3FF5910C R/W

LEDC_LSCH6_DUTY_REG Initial duty cycle for low-speed channel 6 0x3FF59120 R/W

LEDC_LSCH7_DUTY_REG Initial duty cycle for low-speed channel 7 0x3FF59134 R/W

LEDC_LSCH0_DUTY_R_REG Current duty cycle for low-speed channel 0 0x3FF590B0 RO

LEDC_LSCH1_DUTY_R_REG Current duty cycle for low-speed channel 1 0x3FF590C4 RO

LEDC_LSCH2_DUTY_R_REG Current duty cycle for low-speed channel 2 0x3FF590D8 RO

LEDC_LSCH3_DUTY_R_REG Current duty cycle for low-speed channel 3 0x3FF590EC RO

LEDC_LSCH4_DUTY_R_REG Current duty cycle for low-speed channel 4 0x3FF59100 RO

LEDC_LSCH5_DUTY_R_REG Current duty cycle for low-speed channel 5 0x3FF59114 RO

LEDC_LSCH6_DUTY_R_REG Current duty cycle for low-speed channel 6 0x3FF59128 RO

LEDC_LSCH7_DUTY_R_REG Current duty cycle for low-speed channel 7 0x3FF5913C RO

Timer registers

LEDC_HSTIMER0_CONF_REG High-speed timer 0 configuration 0x3FF59140 R/W

LEDC_HSTIMER1_CONF_REG High-speed timer 1 configuration 0x3FF59148 R/W

LEDC_HSTIMER2_CONF_REG High-speed timer 2 configuration 0x3FF59150 R/W

LEDC_HSTIMER3_CONF_REG High-speed timer 3 configuration 0x3FF59158 R/W

LEDC_HSTIMER0_VALUE_REG High-speed timer 0 current counter value 0x3FF59144 RO

LEDC_HSTIMER1_VALUE_REG High-speed timer 1 current counter value 0x3FF5914C RO

LEDC_HSTIMER2_VALUE_REG High-speed timer 2 current counter value 0x3FF59154 RO

LEDC_HSTIMER3_VALUE_REG High-speed timer 3 current counter value 0x3FF5915C RO

LEDC_HSTIMER0_CONF_REG Low-speed timer 0 configuration 0x3FF59140 R/W

LEDC_HSTIMER1_CONF_REG Low-speed timer 1 configuration 0x3FF59148 R/W

LEDC_HSTIMER2_CONF_REG Low-speed timer 2 configuration 0x3FF59150 R/W

LEDC_HSTIMER3_CONF_REG Low-speed timer 3 configuration 0x3FF59158 R/W

LEDC_HSTIMER0_VALUE_REG Low-speed timer 0 current counter value 0x3FF59144 RO

LEDC_HSTIMER1_VALUE_REG Low-speed timer 1 current counter value 0x3FF5914C RO

LEDC_HSTIMER2_VALUE_REG Low-speed timer 2 current counter value 0x3FF59154 RO

LEDC_HSTIMER3_VALUE_REG Low-speed timer 3 current counter value 0x3FF5915C RO

Interrupt registers

LEDC_INT_RAW_REG Raw interrupt status 0x3FF59180 RO

LEDC_INT_ST_REG Masked interrupt status 0x3FF59184 RO

LEDC_INT_ENA_REG Interrupt enable bits 0x3FF59188 R/W

LEDC_INT_CLR_REG Interrupt clear bits 0x3FF5918C WO

Espressif Systems 70 ESP32 Technical Reference Manual V1.0

5.4 Registers 5 LED_PWM

5.4 Registers

(reserved)

31 4

0x00000000

LEDC_SIG_OUT_EN_HSCHn

LEDC_IDLE_LV_HSCHn

1 0

LEDC_IDLE_LV_HSCHn This bit is used to control the output value when high-speed channel n is

inactive. (R/W)

LEDC_SIG_OUT_EN_HSCHn This is the output enable control bit for high-speed channel n. (R/W)

LEDC_TIMER_SEL_HSCHn There are four high-speed timers. These two bits are used to select one

of them for high-speed channel n: (R/W)

0: select hstimer0;

1: select hstimer1;

2: select hstimer2;

3: select hstimer3.

LEDC_TIMER_SEL_HSCHn

Reset

(reserved)

31 20

0x0000

19 0

LEDC_HPOINT_HSCHn

0x000000

LEDC_HPOINT_HSCHn The output value changes to high when htimerx(x=[0,3]) selected by high-

speed channel n has reached reg_hpoint_hschn[19:0]. (R/W)

Reset

Espressif Systems 71 ESP32 Technical Reference Manual V1.0

5.4 Registers 5 LED_PWM

(reserved)

31 25

0x00

24 0

LEDC_DUTY_HSCHn

0x0000000

LEDC_DUTY_HSCHn The register is used to control output duty. When hstimerx(x=[0,3]) selected

by high-speed channel n has reached reg_lpoint_hschn, the output signal changes to low. (R/W)

reg_lpoint_hschn=(reg_hpoint_hschn[19:0]+reg_duty_hschn[24:4]) (1)

reg_lpoint_hschn=(reg_hpoint_hschn[19:0]+reg_duty_hschn[24:4] +1) (2)

See the Functional Description for more information on when (1) or (2) is chosen.

LEDC_DUTY_INC_HSCHn

LEDC_DUTY_START_HSCHn

29 20

LEDC_DUTY_NUM_HSCHn

0x000

LEDC_DUTY_CYCLE_HSCHn

19 10

0x000

LEDC_DUTY_SCALE_HSCHn

9 0

0x000

Reset

LEDC_DUTY_START_HSCHn When REG_DUTY_NUM_HSCHn, REG_DUTY_CYCLE_HSCHn and

REG_DUTY_SCALE_HSCHn has been configured, these register won’t take effect until

REG_DUTY_START_HSCHn is set. This bit is automatically cleared by hardware. (R/W)

LEDC_DUTY_INC_HSCHn This register is used to increase or decrease the duty of output signal for

high-speed channel n. (R/W)

LEDC_DUTY_NUM_HSCHn This register is used to control the number of times the duty cycle is

increased or decreased for high-speed channel n. (R/W)

LEDC_DUTY_CYCLE_HSCHn This register is used to increase or decrease the duty cycle every

REG_DUTY_CYCLE_HSCHn cycles for high-speed channel n. (R/W)

LEDC_DUTY_SCALE_HSCHn This register is used to increase or decrease the step scale for high-

speed channel n. (R/W)

Espressif Systems 72 ESP32 Technical Reference Manual V1.0

5.4 Registers 5 LED_PWM

(reserved)

31 25

0x00

24 0

LEDC_DUTY_HSCHn_R

0x0000000

LEDC_DUTY_HSCHn_R This register represents the current duty cycle of the output signal for high-

speed channel n. (RO)

(reserved)

31 5

0x0000000

LEDC_PARA_UP_LSCHn

LEDC_SIG_OUT_EN_LSCHn

LEDC_IDLE_LV_LSCHn

1 0

LEDC_PARA_UP_LSCHn This bit is used to update register LEDC_LSCHn_HPOINT and

LEDC_LSCHn_DUTY for low-speed channel n. (R/W)

Reset

LEDC_TIMER_SEL_LSCHn

Reset

LEDC_IDLE_LV_LSCHn This bit is used to control the output value when low-speed channel n is

inactive. (R/W)

LEDC_SIG_OUT_EN_LSCHn This is the output enable control bit for low-speed channel n. (R/W)

LEDC_TIMER_SEL_LSCHn There are four low speed timers, the two bits are used to select one of

them for low-speed channel n. (R/W)

0: select lstimer0;

1: select lstimer1;

2: select lstimer2;

3: select lstimer3.

Espressif Systems 73 ESP32 Technical Reference Manual V1.0

5.4 Registers 5 LED_PWM

(reserved)

31 20

0x0000

19 0

LEDC_HPOINT_LSCHn

0x000000

LEDC_HPOINT_LSCHn The output value changes to high when lstimerx(x=[0,3]) selected by low-

speed channel n has reached reg_hpoint_lschn[19:0]. (R/W)

(reserved)

31 25

0x00

24 0

LEDC_DUTY_LSCHn

0x0000000

LEDC_DUTY_LSCHn The register is used to control output duty. When lstimerx(x=[0,3]) chosen by

low-speed channel n has reached reg_lpoint_lschn,the output signal changes to low. (R/W)

reg_lpoint_lschn=(reg_hpoint_lschn[19:0]+reg_duty_lschn[24:4]) (1)

reg_lpoint_lschn=(reg_hpoint_lschn[19:0]+reg_duty_lschn[24:4] +1) (2)

See the Functional Description for more information on when (1) or (2) is chosen.

Reset

Espressif Systems 74 ESP32 Technical Reference Manual V1.0

5.4 Registers 5 LED_PWM

LEDC_DUTY_INC_LSCHn

LEDC_DUTY_START_LSCHn

29 20

LEDC_DUTY_NUM_LSCHn

0x000

LEDC_DUTY_CYCLE_LSCHn

19 10

0x000

LEDC_DUTY_SCALE_LSCHn

9 0

0x000

LEDC_DUTY_START_LSCHn When reg_duty_num_hschn, reg_duty_cycle_hschn and

reg_duty_scale_hschn has been configured, these settings won’t take effect until set

reg_duty_start_hschn. This bit is automatically cleared by hardware. (R/W)

LEDC_DUTY_INC_LSCHn This register is used to increase or decrease the duty of output signal for

low-speed channel n. (R/W)

LEDC_DUTY_NUM_LSCHn This register is used to control the number of times the duty cycle is

increased or decreasedfor low-speed channel n. (R/W)

LEDC_DUTY_CYCLE_LSCHn This register is used to increase or decrease the duty every

reg_duty_cycle_lschn cycles for low-speed channel n. (R/W)

LEDC_DUTY_SCALE_LSCHn This register is used to increase or decrease the step scale for low-

speed channel n. (R/W)

Reset

(reserved)

31 25

0x00

24 0

LEDC_DUTY_LSCHn_R

0x0000000

LEDC_DUTY_LSCHn_R This register represents the current duty of the output signal for low-speed

channel n. (RO)

Reset

Espressif Systems 75 ESP32 Technical Reference Manual V1.0

5.4 Registers 5 LED_PWM

(reserved)

31 26

0x00

LEDC_HSTIMERx_PAUSE

LEDC_HSTIMERx_RST

LEDC_TICK_SEL_HSTIMERx

22 5

LEDC_DIV_NUM_HSTIMERx

0x00000

LEDC_HSTIMERx_LIM

4 0

0x00

LEDC_TICK_SEL_HSTIMERx This bit is used to select APB_CLK or REF_TICK for high-speed timer

x. (R/W)

1: APB_CLK;

0: REF_TICK.

LEDC_HSTIMERx_RST This bit is used to reset high-speed timer x. The counter value will be 0 after

reset. (R/W)

LEDC_HSTIMERx_PAUSE This bit is used to suspend the counter in high-speed timer x. (R/W)

LEDC_DIV_NUM_HSTIMERx This register is used to configure the division factor for the divider in

high-speed timer x. The least significant eight bits represent the fractional part. (R/W)

LEDC_HSTIMERx_LIM This register is used to control the range of the counter in high-speed timer

x. The counter range is [0,2**reg_hstimerx_lim], the maximum bit width for counter is 20. (R/W)

Reset

(reserved)

31 20

0x0000

19 0

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

LEDC_HSTIMERx_CNT

LEDC_HSTIMERx_CNT Software can read this register to get the current counter value of high-speed

timer x. (RO)

Reset

Espressif Systems 76 ESP32 Technical Reference Manual V1.0

5.4 Registers 5 LED_PWM

(reserved)

31 27

0x00

LEDC_LSTIMERx_PARA_UP

LEDC_LSTIMERx_PAUSE

LEDC_LSTIMERx_RST

LEDC_TICK_SEL_LSTIMERx

22 5

LEDC_DIV_NUM_LSTIMERx

0x00000

LEDC_LSTIMERx_LIM

4 0

0x00

LEDC_LSTIMERx_PARA_UP Set this bit to update REG_DIV_NUM_LSTIMEx and

REG_LSTIMERx_LIM. (R/W)

LEDC_TICK_SEL_LSTIMERx This bit is used to select SLOW_CLK or REF_TICK for low-speed timer

x. (R/W)

1: SLOW_CLK;

0: REF_TICK.

LEDC_LSTIMERx_RST This bit is used to reset low-speed timer x. The counter will be 0 after reset.

(R/W)

LEDC_LSTIMERx_PAUSE This bit is used to suspend the counter in low-speed timer x. (R/W)

LEDC_DIV_NUM_LSTIMERx This register is used to configure the division factor for the divider in

low-speed timer x. The least significant eight bits represent the fractional part. (R/W)

LEDC_LSTIMERx_LIM This register is used to control the range of the counter in low-speed timer x.

The counter range is [0,2**reg_lstimerx_lim], the max bit width for counter is 20. (R/W)

Reset

(reserved)

31 20

0x0000

19 0

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

LEDC_LSTIMERx_CNT

LEDC_LSTIMERx_CNT Software can read this register to get the current counter value of low-speed

timer x. (RO)

Reset

Espressif Systems 77 ESP32 Technical Reference Manual V1.0

5.4 Registers 5 LED_PWM

(reserved)

31 24

0 0 0 0 0 0 0 0

LEDC_DUTY_CHNG_END_LSCH7_INT_RAW

LEDC_DUTY_CHNG_END_LSCH6_INT_RAW

LEDC_DUTY_CHNG_END_LSCH0_INT_RAW

LEDC_DUTY_CHNG_END_LSCH1_INT_RAW

LEDC_DUTY_CHNG_END_LSCH2_INT_RAW

LEDC_DUTY_CHNG_END_LSCH3_INT_RAW

LEDC_DUTY_CHNG_END_LSCH4_INT_RAW

LEDC_DUTY_CHNG_END_LSCH5_INT_RAW

LEDC_DUTY_CHNG_END_HSCH5_INT_RAW

LEDC_DUTY_CHNG_END_HSCH4_INT_RAW

LEDC_DUTY_CHNG_END_HSCH6_INT_RAW

LEDC_DUTY_CHNG_END_HSCH7_INT_RAW

LEDC_DUTY_CHNG_END_HSCH1_INT_RAW

LEDC_DUTY_CHNG_END_HSCH2_INT_RAW

LEDC_DUTY_CHNG_END_HSCH3_INT_RAW

LEDC_DUTY_CHNG_END_HSCH0_INT_RAW

LEDC_LSTIMER0_OVF_INT_RAW

LEDC_HSTIMER2_OVF_INT_RAW

LEDC_HSTIMER3_OVF_INT_RAW

LEDC_LSTIMER1_OVF_INT_RAW

LEDC_LSTIMER2_OVF_INT_RAW

LEDC_LSTIMER3_OVF_INT_RAW

LEDC_HSTIMER1_OVF_INT_RAW

LEDC_DUTY_CHNG_END_LSCHn_INT_RAW The raw interrupt status bit for the

LEDC_DUTY_CHNG_END_LSCHn_INT interrupt. (RO)

LEDC_DUTY_CHNG_END_HSCHn_INT_RAW The raw interrupt status bit for the

LEDC_DUTY_CHNG_END_HSCHn_INT interrupt. (RO)

LEDC_LSTIMERx_OVF_INT_RAW The raw interrupt status bit for the LEDC_LSTIMERx_OVF_INT

interrupt. (RO)

LEDC_HSTIMERx_OVF_INT_RAW The raw interrupt status bit for the LEDC_HSTIMERx_OVF_INT

interrupt. (RO)

LEDC_HSTIMER0_OVF_INT_RAW

Reset

(reserved)

31 24

0 0 0 0 0 0 0 0

LEDC_DUTY_CHNG_END_LSCH7_INT_ST

LEDC_DUTY_CHNG_END_LSCH5_INT_ST

LEDC_DUTY_CHNG_END_LSCH6_INT_ST

LEDC_DUTY_CHNG_END_LSCH2_INT_ST

LEDC_DUTY_CHNG_END_LSCH3_INT_ST

LEDC_DUTY_CHNG_END_LSCH4_INT_ST

LEDC_DUTY_CHNG_END_LSCH0_INT_ST

LEDC_DUTY_CHNG_END_LSCH1_INT_ST

LEDC_DUTY_CHNG_END_HSCH5_INT_ST

LEDC_DUTY_CHNG_END_HSCH6_INT_ST

LEDC_DUTY_CHNG_END_HSCH7_INT_ST

LEDC_DUTY_CHNG_END_HSCH2_INT_ST

LEDC_DUTY_CHNG_END_HSCH3_INT_ST

LEDC_DUTY_CHNG_END_HSCH4_INT_ST

LEDC_DUTY_CHNG_END_HSCH1_INT_ST

LEDC_LSTIMER2_OVF_INT_ST

LEDC_LSTIMER3_OVF_INT_ST

LEDC_DUTY_CHNG_END_HSCH0_INT_ST

LEDC_HSTIMER3_OVF_INT_ST

LEDC_LSTIMER0_OVF_INT_ST

LEDC_LSTIMER1_OVF_INT_ST

LEDC_HSTIMER0_OVF_INT_ST

LEDC_HSTIMER1_OVF_INT_ST

LEDC_HSTIMER2_OVF_INT_ST

Reset

LEDC_DUTY_CHNG_END_LSCHn_INT_ST The masked interrupt status bit for the

LEDC_DUTY_CHNG_END_LSCHn_INT interrupt. (RO)

LEDC_DUTY_CHNG_END_HSCHn_INT_ST The masked interrupt status bit for the

LEDC_DUTY_CHNG_END_HSCHn_INT interrupt. (RO)

LEDC_LSTIMERx_OVF_INT_ST The masked interrupt status bit for the LEDC_LSTIMERx_OVF_INT

interrupt. (RO)

LEDC_HSTIMERx_OVF_INT_ST The masked interrupt status bit for the LEDC_HSTIMERx_OVF_INT

interrupt. (RO)

Espressif Systems 78 ESP32 Technical Reference Manual V1.0

5.4 Registers 5 LED_PWM

(reserved)

31 24

0 0 0 0 0 0 0 0

LEDC_DUTY_CHNG_END_LSCH2_INT_ENA

LEDC_DUTY_CHNG_END_LSCH3_INT_ENA

LEDC_DUTY_CHNG_END_LSCH7_INT_ENA

LEDC_DUTY_CHNG_END_LSCH4_INT_ENA

LEDC_DUTY_CHNG_END_LSCH5_INT_ENA

LEDC_DUTY_CHNG_END_LSCH6_INT_ENA

LEDC_DUTY_CHNG_END_LSCH0_INT_ENA

LEDC_DUTY_CHNG_END_LSCH1_INT_ENA

LEDC_DUTY_CHNG_END_HSCH5_INT_ENA

LEDC_DUTY_CHNG_END_HSCH6_INT_ENA

LEDC_DUTY_CHNG_END_HSCH7_INT_ENA

LEDC_DUTY_CHNG_END_HSCH4_INT_ENA

LEDC_LSTIMER3_OVF_INT_ENA

LEDC_DUTY_CHNG_END_HSCH0_INT_ENA

LEDC_DUTY_CHNG_END_HSCH1_INT_ENA

LEDC_DUTY_CHNG_END_HSCH2_INT_ENA

LEDC_DUTY_CHNG_END_HSCH3_INT_ENA

LEDC_LSTIMER0_OVF_INT_ENA

LEDC_LSTIMER1_OVF_INT_ENA

LEDC_LSTIMER2_OVF_INT_ENA

LEDC_HSTIMER1_OVF_INT_ENA

LEDC_HSTIMER2_OVF_INT_ENA

LEDC_HSTIMER3_OVF_INT_ENA

LEDC_DUTY_CHNG_END_LSCHn_INT_ENA The interrupt enable bit for the

LEDC_DUTY_CHNG_END_LSCHn_INT interrupt. (R/W)

LEDC_DUTY_CHNG_END_HSCHn_INT_ENA The interrupt enable bit for the

LEDC_DUTY_CHNG_END_HSCHn_INT interrupt. (R/W)

LEDC_LSTIMERx_OVF_INT_ENA The interrupt enable bit for the LEDC_LSTIMERx_OVF_INT inter-

rupt. (R/W)

LEDC_HSTIMERx_OVF_INT_ENA The interrupt enable bit for the LEDC_HSTIMERx_OVF_INT inter-

rupt. (R/W)

LEDC_HSTIMER0_OVF_INT_ENA

Reset

(reserved)

31 24

0 0 0 0 0 0 0 0

LEDC_DUTY_CHNG_END_LSCH7_INT_CLR

LEDC_DUTY_CHNG_END_LSCH6_INT_CLR

LEDC_DUTY_CHNG_END_LSCH3_INT_CLR

LEDC_DUTY_CHNG_END_LSCH4_INT_CLR

LEDC_DUTY_CHNG_END_LSCH5_INT_CLR

LEDC_DUTY_CHNG_END_LSCH0_INT_CLR

LEDC_DUTY_CHNG_END_LSCH1_INT_CLR

LEDC_DUTY_CHNG_END_LSCH2_INT_CLR

LEDC_DUTY_CHNG_END_HSCH5_INT_CLR

LEDC_DUTY_CHNG_END_HSCH6_INT_CLR

LEDC_DUTY_CHNG_END_HSCH7_INT_CLR

LEDC_DUTY_CHNG_END_HSCH4_INT_CLR

LEDC_DUTY_CHNG_END_HSCH1_INT_CLR

LEDC_LSTIMER3_OVF_INT_CLR

LEDC_DUTY_CHNG_END_HSCH0_INT_CLR

LEDC_DUTY_CHNG_END_HSCH2_INT_CLR

LEDC_DUTY_CHNG_END_HSCH3_INT_CLR

LEDC_LSTIMER0_OVF_INT_CLR

LEDC_LSTIMER1_OVF_INT_CLR

LEDC_LSTIMER2_OVF_INT_CLR

LEDC_HSTIMER1_OVF_INT_CLR

LEDC_HSTIMER2_OVF_INT_CLR

LEDC_HSTIMER3_OVF_INT_CLR

LEDC_HSTIMER0_OVF_INT_CLR

Reset

LEDC_DUTY_CHNG_END_LSCHn_INT_CLR Set this bit to clear the

LEDC_DUTY_CHNG_END_LSCHn_INT interrupt. (WO)

LEDC_DUTY_CHNG_END_HSCHn_INT_CLR Set this bit to clear the

LEDC_DUTY_CHNG_END_HSCHn_INT interrupt. (WO)

LEDC_LSTIMERx_OVF_INT_CLR Set this bit to clear the LEDC_LSTIMERx_OVF_INT interrupt. (WO)

LEDC_HSTIMERx_OVF_INT_CLR Set this bit to clear the LEDC_HSTIMERx_OVF_INT interrupt.

(WO)

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5.4 Registers 5 LED_PWM

(reserved)

31 1

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

LEDC_APB_CLK_SEL This bit is used to set the frequency of SLOW_CLK. (R/W)

0: 8 MHz;

1: 80 MHz.

LEDC_APB_CLK_SEL

Reset

Espressif Systems 80 ESP32 Technical Reference Manual V1.0

6 REMOTE CONTROLLER PERIPHERAL

6. Remote Controller Peripheral

6.1 Introduction

The RMT (Remote Control) module is primarily designed to send and receive infrared remote control signals that

use on-off-keying of a carrier frequency, but due to its design it can be used to generate various types of signals.

An RMT transmitter does this by reading consecutive duration values for an active and inactive output from the

built-in RAM block, optionally modulating it with a carrier wave. A receiver will inspect its input signal, optionally

filtering it, and will place the lengths of time the signal is active and inactive in the RAM block.

The RMT module has eight channels, numbered 0 to 7; registers, signals and blocks that are duplicated every

channel are indicated by an n as a placeholder for the channel number.

6.2 Functional Description

6.2.1 RMT Architecture

Figure 14: RMT Architecture

The RMT module contains eight channels; each channel has a transmitter and receiver, of which one can be

active per channel. The 8 channels share a 512x32-bit RAM block which can be read and written by the

processor cores over the APB bus, as well as read by the transmitters and written by the receivers. The

transmitted signal can optionally be modulated by a carrier wave. Each channel is clocked by a divided-down

signal derived from either the APB bus clock or REF_TICK.

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6.2 Functional Description 6 REMOTE CONTROLLER PERIPHERAL

6.2.2 RMT RAM

Figure 15: Data Structure

The data structure in RAM is shown in Figure 15. Each 32-bit value contains two 16-bit entries, containing two

fields each: ”level” indicates whether a high-level or a low-level value is to be sent or was received, ”period” is the

duration (in channel clock periods) for which the level lasts. A period of zero is interpreted as an end marker: the

transmitter will stop transmitting once it has read this and the receiver will write this once it has detected that the

signal it received has gone idle.

Normally, only one block of 64x32-bit worth of data can be sent or received. If the data size is larger than this

block size, blocks can either be extended or the channel can be configured for wraparound mode.

The RMT RAM can be accessed via APB bus. The initial address is RMT base address + 0x800. The RAM block

is divided into eight 64x32-bit blocks. By default, each channel uses one block (block 0 for channel 0, block 1 for

channel 1, and so on). Users can extend the memory for a specific channel by configuring RMT_MEM_SIZE_CHn

range for channel n is start_addr_CHn to end_addr_CHn, which are defined by:

start_addr_chn = RMT base address + 0x800 + 64 ∗ 4 ∗ n, and

end_addr_chn = RMT base address + 0x800 + �64 ∗ 4 ∗ n + 64 ∗ 4 ∗ RMT_MEM_SIZE_CHn�mod�512 ∗ 4�

To protect a receiver from overwriting the blocks a transmitter is about to transmit, RMT_MEM_OWNER_CHn

can be configured to assign the owner, i.e. transmitter or receiver, of channel n’s RAM block. If this ownership is

violated, the RMT_CHn_ERR interrupt will be generated.

6.2.3 Clock

The main clock for a channel is generated by taking either the 80 MHz APB clock or REF_TICK (usually 1MHz),

according to the state of RMT_REF_ALWAYS_ON_CHn. For more information on the clock sources, please refer

to Chapter Reset And Clock. This gets then scaled down using a configurable 8-bit divider to create the channel

clock, to be used by both the carrier wave generator as well as by the counter. The divider value can be set by

configuring RMT_DIV_CNT_CHn.

6.2.4 Transmitter

When the RMT_TX_START_CHn register is 1, the transmitter of channel n will start reading data from RAM and

sending it. The transmitter will receive a 32-bits value each time it reads from RAM. Of these 32 bits, the low

16-bit entry is sent first, the high entry second.

To transmit more data than fits in the channels RAM, wraparound mode can be enabled. In this mode, when the

transmitter has reached the last entry in the channels memory, it will loop back to the first byte. To use this

mechanism to send more data than fits in the channels RAM, fill the RAM with the initial events and set

RMT_CHn_TX_LIM_REG to cause an RMT_CHn_TX_THR_EVENT_INT interrupt before the wraparound

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6.2 Functional Description 6 REMOTE CONTROLLER PERIPHERAL

happens. Then, when the interrupt happens, the data that was already sent should be replaced with subsequent

events: when the wraparound happens the transmitter will seamlessly continue sending the new events.

With or without wraparound mode enabled, transmission ends when an entry with a length of 0 is encountered.

When this happens, the transmitter will generate a RMT_CHn_TX_END_INT interrupt, and return to the idle state.

When a transmitter is in the idle state users can configure RMT_IDLE_OUT_EN_CHn and

RMT_IDLE_OUT_LV_CHn to control the transmitter output manually.

The output of the transmitter can be modulated using a carrier wave by setting RMT_CARRIER_EN_CHn. The

carrier frequency and duty cycle can be configured by configuring its high and low durations, in channel clock

cycles, in RMT_CARRIER_HIGH_CHn and RMT_CARRIER_HIGH_CHn.

6.2.5 Receiver

When RMT_RX_EN_CHn is set to 1, the receiver in channel n becomes active, measuring the duration between

input signal edges. These will be written as period/level value pairs to the channel RAM in the same fashion as

the transmitter sends them. Receiving ends when the receiver detects no change in signal level for more than

RMT_IDLE_THRES_CHn channel clock ticks; the receiver will write a final entry with period 0, generate an

RMT_CHn_RX_END_INT_RAW interrupt and return to the idle state.

The receiver has an input signal filter which can be configured using RMT_RX_FILTER_EN_CHn: The filter will

remove pulses with of length less than RMT_RX_FILTER_THRES_CHn APB clock periods.

When the RMT module is inactive, the RAM can be put into low-power mode by setting the RMT_MEM_PD

6.2.6 Interrupts

• RMT_CHn_TX_THR_EVENT_INT: Triggered when the number of events the transmitter has sent matches

the contents of the RMT_CHn_TX_LIM_REG register.

• RMT_CHn_TX_END_INT: Triggered when the transmitter has finished transmitting the signal.

• RMT_CHn_RX_END_INT: Triggered when the receiver has finished receiving a signal.

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6.3 Register Summary 6 REMOTE CONTROLLER PERIPHERAL

6.3 Register Summary

Name Description Address Access

Configuration registers

RMT_CH0CONF0_REG Channel 0 config register 0 0x3FF56020 R/W

RMT_CH0CONF1_REG Channel 0 config register 1 0x3FF56024 R/W

RMT_CH1CONF0_REG Channel 1 config register 0 0x3FF56028 R/W

RMT_CH1CONF1_REG Channel 1 config register 1 0x3FF5602C R/W

RMT_CH2CONF0_REG Channel 2 config register 0 0x3FF56030 R/W

RMT_CH2CONF1_REG Channel 2 config register 1 0x3FF56034 R/W

RMT_CH3CONF0_REG Channel 3 config register 0 0x3FF56038 R/W

RMT_CH3CONF1_REG Channel 3 config register 1 0x3FF5603C R/W

RMT_CH4CONF0_REG Channel 4 config register 0 0x3FF56040 R/W

RMT_CH4CONF1_REG Channel 4 config register 1 0x3FF56044 R/W

RMT_CH5CONF0_REG Channel 5 config register 0 0x3FF56048 R/W

RMT_CH5CONF1_REG Channel 5 config register 1 0x3FF5604C R/W

RMT_CH6CONF0_REG Channel 6 config register 0 0x3FF56050 R/W

RMT_CH6CONF1_REG Channel 6 config register 1 0x3FF56054 R/W

RMT_CH7CONF0_REG Channel 7 config register 0 0x3FF56058 R/W

RMT_CH7CONF1_REG Channel 7 config register 1 0x3FF5605C R/W

Interrupt registers

RMT_INT_RAW_REG Raw interrupt status 0x3FF560A0 RO

RMT_INT_ST_REG Masked interrupt status 0x3FF560A4 RO

RMT_INT_ENA_REG Interrupt enable bits 0x3FF560A8 R/W

RMT_INT_CLR_REG Interrupt clear bits 0x3FF560AC WO

Carrier wave duty cycle registers

RMT_CH0CARRIER_DUTY_REG Channel 0 duty cycle configuration register 0x3FF560B0 R/W

RMT_CH1CARRIER_DUTY_REG Channel 1 duty cycle configuration register 0x3FF560B4 R/W

RMT_CH2CARRIER_DUTY_REG Channel 2 duty cycle configuration register 0x3FF560B8 R/W

RMT_CH3CARRIER_DUTY_REG Channel 3 duty cycle configuration register 0x3FF560BC R/W

RMT_CH4CARRIER_DUTY_REG Channel 4 duty cycle configuration register 0x3FF560C0 R/W

RMT_CH5CARRIER_DUTY_REG Channel 5 duty cycle configuration register 0x3FF560C4 R/W

RMT_CH6CARRIER_DUTY_REG Channel 6 duty cycle configuration register 0x3FF560C8 R/W

RMT_CH7CARRIER_DUTY_REG Channel 7 duty cycle configuration register 0x3FF560CC R/W

Tx event configuration registers

RMT_CH0_TX_LIM_REG Channel 0 Tx event configuration register 0x3FF560D0 R/W

RMT_CH1_TX_LIM_REG Channel 1 Tx event configuration register 0x3FF560D4 R/W

RMT_CH2_TX_LIM_REG Channel 2 Tx event configuration register 0x3FF560D8 R/W

RMT_CH3_TX_LIM_REG Channel 3 Tx event configuration register 0x3FF560DC R/W

RMT_CH4_TX_LIM_REG Channel 4 Tx event configuration register 0x3FF560E0 R/W

RMT_CH5_TX_LIM_REG Channel 5 Tx event configuration register 0x3FF560E4 R/W

RMT_CH6_TX_LIM_REG Channel 6 Tx event configuration register 0x3FF560E8 R/W

RMT_CH7_TX_LIM_REG Channel 7 Tx event configuration register 0x3FF560EC R/W

Other registers

RMT_APB_CONF_REG RMT-wide configuration register 0x3FF560F0 R/W

Espressif Systems 84 ESP32 Technical Reference Manual V1.0

6.4 Registers 6 REMOTE CONTROLLER PERIPHERAL

6.4 Registers

(reserved)

RMT_MEM_PD

0x0

RMT_CARRIER_EN_CHn

RMT_CARRIER_OUT_LV_CHn

RMT_MEM_SIZE_CHn

27 24

0x01

RMT_IDLE_THRES_CHn

23 8

0x01000

RMT_DIV_CNT_CHn

7 0

0x002

RMT_MEM_PD This bit is used power down the entire RMT RAM block (Only exists in

RMT_CH0CONF0). 1: memory is powered down 0: memory is powered up (R/W)

RMT_CARRIER_OUT_LV_CHn This bit is used to configure when the carrier wave is transmitted. 1:

transmit on low output level, 0: transmit on high output level. (R/W)

RMT_CARRIER_EN_CHn This is the carrier modulation enable control bit for channeln. 1: carrier

modulation enabled 0: carrier modulation disabled (R/W)

RMT_MEM_SIZE_CHn This register is used to configure the amount of memory blocks allocated to

channel n (R/W)

RMT_IDLE_THRES_CHn In receive mode, when no edge is detected on the input signal for longer

than reg_idle_thres_chn channel clock cycles, the receive process is finished. (R/W)

RMT_DIV_CNT_CHn This register is used to set the divider for the channel clock of channel n. (R/W)

Reset

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6.4 Registers 6 REMOTE CONTROLLER PERIPHERAL

(reserved)

31 20

0x0000

RMT_IDLE_OUT_LV_CHn

RMT_IDLE_OUT_EN_CHn

RMT_REF_CNT_RST_CHn

RMT_REF_ALWAYS_ON_CHn

15 8

RMT_RX_FILTER_THRES_CHn

0x00F

RMT_RX_FILTER_EN_CHn

(reserved)

RMT_MEM_WR_RST_CHn

RMT_MEM_RD_RST_CHn

RMT_MEM_OWNER_CHn

RMT_TX_CONTI_MODE_CHn

RMT_RX_EN_CHn

RMT_IDLE_OUT_EN_CHn This is the output enable control bit for channel n in IDLE state. (R/W)

RMT_IDLE_OUT_LV_CHn This bit configures the output signals level for channel n in IDLE state.

(R/W)

RMT_REF_ALWAYS_ON_CHn This bit is used to select the channels base clock. 1:clk_apb;

0:clk_ref. (R/W)

RMT_REF_CNT_RST_CHn Setting this bit resets the clock divider of channel n. (R/W)

RMT_RX_FILTER_THRES_CHn In receive mode, channel n ignores input pulse when the pulse width

is smaller than this value, in APB clock periods. (R/W)

RMT_RX_FILTER_EN_CHn This is the receive filter enable bit for channel n. (R/W)

RMT_TX_CONTI_MODE_CHn If this bit is set, instead of going to idle when the transmission ends,

the transmitter will restart transmission. This results in a repeating output signal. (R/W)

RMT_MEM_OWNER_CHn This bit marks channel n’s RAM block ownership. 1: receiver uses the

RAM; 0: transmitter uses the RAM. (R/W)

RMT_TX_START_CHn

Reset

RMT_MEM_RD_RST_CHn Set this bit to reset read ram address for channel n by transmitter access.

(R/W)

RMT_MEM_WR_RST_CHn Set this bit to reset write ram address for channel n by receiver access.

(R/W)

RMT_RX_EN_CHn Set this bit to enable receiving data on channel n. (R/W)

RMT_TX_START_CHn Set this bit to start sending data on channel n. (R/W)

Espressif Systems 86 ESP32 Technical Reference Manual V1.0

6.4 Registers 6 REMOTE CONTROLLER PERIPHERAL

RMT_CH7_TX_THR_EVENT_INT_RAW

RMT_CH1_TX_THR_EVENT_INT_RAW

RMT_CH2_TX_THR_EVENT_INT_RAW

RMT_CH3_TX_THR_EVENT_INT_RAW

RMT_CH4_TX_THR_EVENT_INT_RAW

RMT_CH5_TX_THR_EVENT_INT_RAW

RMT_CH6_TX_THR_EVENT_INT_RAW

RMT_CH7_ERR_INT_RAW

RMT_CH7_TX_END_INT_RAW

RMT_CH7_RX_END_INT_RAW

RMT_CH0_TX_THR_EVENT_INT_RAW

RMT_CH6_TX_END_INT_RAW

RMT_CH6_RX_END_INT_RAW

RMT_CH6_ERR_INT_RAW

RMT_CH5_RX_END_INT_RAW

RMT_CH5_ERR_INT_RAW

RMT_CH4_RX_END_INT_RAW

RMT_CH4_ERR_INT_RAW

RMT_CH5_TX_END_INT_RAW

RMT_CH3_ERR_INT_RAW

RMT_CH4_TX_END_INT_RAW

RMT_CH3_TX_END_INT_RAW

RMT_CH3_RX_END_INT_RAW

RMT_CH2_TX_END_INT_RAW

RMT_CH2_RX_END_INT_RAW

RMT_CH2_ERR_INT_RAW

RMT_CH1_RX_END_INT_RAW

RMT_CH1_ERR_INT_RAW

RMT_CH0_RX_END_INT_RAW

RMT_CH0_ERR_INT_RAW

RMT_CH1_TX_END_INT_RAW

RMT_CHn_TX_THR_EVENT_INT_RAW The raw interrupt status bit for the

RMT_CHn_TX_THR_EVENT_INT interrupt. (RO)

RMT_CHn_ERR_INT_RAW The raw interrupt status bit for the RMT_CHn_ERR_INT interrupt. (RO)

RMT_CHn_RX_END_INT_RAW The raw interrupt status bit for the RMT_CHn_RX_END_INT inter-

rupt. (RO)

RMT_CHn_TX_END_INT_RAW The raw interrupt status bit for the RMT_CHn_TX_END_INT interrupt.

(RO)

RMT_CH0_TX_END_INT_RAW

Reset

RMT_CH7_ERR_INT_ST

RMT_CH0_TX_THR_EVENT_INT_ST

RMT_CH7_TX_THR_EVENT_INT_ST

RMT_CH2_TX_THR_EVENT_INT_ST

RMT_CH1_TX_THR_EVENT_INT_ST

RMT_CH3_TX_THR_EVENT_INT_ST

RMT_CH4_TX_THR_EVENT_INT_ST

RMT_CH5_TX_THR_EVENT_INT_ST

RMT_CH6_TX_THR_EVENT_INT_ST

RMT_CH5_RX_END_INT_ST

RMT_CH5_ERR_INT_ST

RMT_CH6_TX_END_INT_ST

RMT_CH6_RX_END_INT_ST

RMT_CH6_ERR_INT_ST

RMT_CH7_TX_END_INT_ST

RMT_CH7_RX_END_INT_ST

RMT_CH4_RX_END_INT_ST

RMT_CH4_ERR_INT_ST

RMT_CH5_TX_END_INT_ST

RMT_CH4_TX_END_INT_ST

RMT_CH3_TX_END_INT_ST

RMT_CH3_RX_END_INT_ST

RMT_CH3_ERR_INT_ST

RMT_CH2_ERR_INT_ST

RMT_CH1_TX_END_INT_ST

RMT_CH1_RX_END_INT_ST

RMT_CH1_ERR_INT_ST

RMT_CH2_TX_END_INT_ST

RMT_CH2_RX_END_INT_ST

RMT_CH0_RX_END_INT_ST

RMT_CH0_ERR_INT_ST

RMT_CHn_TX_THR_EVENT_INT_ST The masked interrupt status bit for the

RMT_CHn_TX_THR_EVENT_INT interrupt. (RO)

RMT_CHn_ERR_INT_ST The masked interrupt status bit for the RMT_CHn_ERR_INT interrupt. (RO)

RMT_CHn_RX_END_INT_ST The masked interrupt status bit for the RMT_CHn_RX_END_INT inter-

rupt. (RO)

RMT_CHn_TX_END_INT_ST The masked interrupt status bit for the RMT_CHn_TX_END_INT inter-

rupt. (RO)

RMT_CH0_TX_END_INT_ST

Reset

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6.4 Registers 6 REMOTE CONTROLLER PERIPHERAL

RMT_CH4_RX_END_INT_ENA

RMT_CH6_TX_THR_EVENT_INT_ENA

RMT_CH7_TX_THR_EVENT_INT_ENA

RMT_CH2_TX_THR_EVENT_INT_ENA

RMT_CH7_ERR_INT_ENA

RMT_CH0_TX_THR_EVENT_INT_ENA

RMT_CH1_TX_THR_EVENT_INT_ENA

RMT_CH3_TX_THR_EVENT_INT_ENA

RMT_CH4_TX_THR_EVENT_INT_ENA

RMT_CH5_TX_THR_EVENT_INT_ENA

RMT_CH7_RX_END_INT_ENA

RMT_CH5_ERR_INT_ENA

RMT_CH6_TX_END_INT_ENA

RMT_CH6_RX_END_INT_ENA

RMT_CH6_ERR_INT_ENA

RMT_CH7_TX_END_INT_ENA

RMT_CH4_ERR_INT_ENA

RMT_CH5_TX_END_INT_ENA

RMT_CH5_RX_END_INT_ENA

RMT_CH3_RX_END_INT_ENA

RMT_CH3_ERR_INT_ENA

RMT_CH4_TX_END_INT_ENA

RMT_CH1_RX_END_INT_ENA

RMT_CH3_TX_END_INT_ENA

RMT_CH2_ERR_INT_ENA

RMT_CH1_ERR_INT_ENA

RMT_CH2_TX_END_INT_ENA

RMT_CH2_RX_END_INT_ENA

RMT_CH1_TX_END_INT_ENA

RMT_CH0_TX_END_INT_ENA

RMT_CH0_RX_END_INT_ENA

RMT_CH0_ERR_INT_ENA

Reset

RMT_CHn_TX_THR_EVENT_INT_ENA The interrupt enable bit for the

RMT_CHn_TX_THR_EVENT_INT interrupt. (R/W)

RMT_CHn_ERR_INT_ENA The interrupt enable bit for the RMT_CHn_ERROR_INT interrupt. (R/W)

RMT_CHn_RX_END_INT_ENA The interrupt enable bit for the RMT_CHn_RX_END_INT interrupt.

(R/W)

RMT_CHn_TX_END_INT_ENA The interrupt enable bit for the RMT_CHn_TX_END_INT interrupt.

(R/W)

RMT_CH4_RX_END_INT_CLR

RMT_CH7_TX_THR_EVENT_INT_CLR

RMT_CH2_TX_THR_EVENT_INT_CLR

RMT_CH7_ERR_INT_CLR

RMT_CH0_TX_THR_EVENT_INT_CLR

RMT_CH1_TX_THR_EVENT_INT_CLR

RMT_CH3_TX_THR_EVENT_INT_CLR

RMT_CH4_TX_THR_EVENT_INT_CLR

RMT_CH5_TX_THR_EVENT_INT_CLR

RMT_CH6_TX_THR_EVENT_INT_CLR

RMT_CH7_RX_END_INT_CLR

RMT_CH5_ERR_INT_CLR

RMT_CH6_TX_END_INT_CLR

RMT_CH6_RX_END_INT_CLR

RMT_CH6_ERR_INT_CLR

RMT_CH7_TX_END_INT_CLR

RMT_CH4_ERR_INT_CLR

RMT_CH5_TX_END_INT_CLR

RMT_CH5_RX_END_INT_CLR

RMT_CH3_RX_END_INT_CLR

RMT_CH3_ERR_INT_CLR

RMT_CH4_TX_END_INT_CLR

RMT_CH1_RX_END_INT_CLR

RMT_CH1_ERR_INT_CLR

RMT_CH3_TX_END_INT_CLR

RMT_CH2_TX_END_INT_CLR

RMT_CH2_RX_END_INT_CLR

RMT_CH2_ERR_INT_CLR

RMT_CH1_TX_END_INT_CLR

RMT_CH0_RX_END_INT_CLR

RMT_CH0_ERR_INT_CLR

RMT_CHn_TX_THR_EVENT_INT_CLR Set this bit to clear the RMT_CHn_TX_THR_EVENT_INT in-

terrupt. (WO)

RMT_CHn_ERR_INT_CLR Set this bit to clear the RMT_CHn_ERRINT interrupt. (WO)

RMT_CH0_TX_END_INT_CLR

Reset

RMT_CHn_RX_END_INT_CLR Set this bit to clear the RMT_CHn_RX_END_INT interrupt. (WO)

RMT_CHn_TX_END_INT_CLR Set this bit to clear the RMT_CHn_TX_END_INT interrupt. (WO)

Espressif Systems 88 ESP32 Technical Reference Manual V1.0

6.4 Registers 6 REMOTE CONTROLLER PERIPHERAL

RMT_CARRIER_HIGH_CHn

31 16

0x00040

15 0

RMT_CARRIER_LOW_CHn

0x00040

RMT_CARRIER_HIGH_CHn This field is used to configure the carrier wave high level duration (in

channel clock periods) for channel n. (R/W)

RMT_CARRIER_LOW_CHn This field is used to configure the carrier wave low level duration (in chan-

nel clock periods) for channel n. (R/W)

(reserved)

31 9

0x000000

8 0

RMT_TX_LIM_CHn

0x080

RMT_TX_LIM_CHn When channel n sends more entries than specified here, it produces a

TX_THR_EVENT interrupt. (R/W)

Reset

(reserved)

31 2

0x00000000

RMT_MEM_TX_WRAP_EN

RMT_MEM_TX_WRAP_EN bit enables wraparound mode: when the transmitter of a channel has

reached the end of its memory block, it will resume sending at the start of its memory region.

(R/W)

Reset

Espressif Systems 89 ESP32 Technical Reference Manual V1.0

7 PULSE_CNT

7. PULSE_CNT

7.1 Introduction

The pulse counter module is designed to count the number of rising and/or falling edges of an input signal. Each

pulse counter unit has a 16-bit signed counter register and two channels that can be configured to either

increment or decrement the counter. Each channel has a signal input that accepts signal edges to be detected,

as well as a control input that can be used to enable or disable the signal input. The inputs have optional filters

that can be used to discard unwanted glitches in the signal.

The pulse counter has eight independent units, referred to as PULSE_CNT_Un.

7.2 Functional Description

7.2.1 Architecture

Figure 16: PULSE_CNT Architecture

The architecture of a pulse counter unit is illustrated in Figure 16. Each unit has two channels: ch0 and ch1,

which are functionally equivalent. Each channel has a signal input as well as a control input which can both be

connected to I/O pads. The counting behaviour on both positive edge as well as negative edge can be

configured separately to increase, decrease or do nothing to the counter value. Separately, for both control signal

levels, the hardware can be configured to modify the edge action: invert it, disable it or do nothing. The counter

itself is a 16-bit signed up/down counter. Its value can be read by software directly, but is also monitored by a set

of comparators which can trigger an interrupt.

7.2.2 Counter Channel Inputs

As stated before, the two inputs of a channel can affect the pulse counter in various ways. The specifics of this

behaviour is set by LCTRL_MODE and HCTRL_MODE for the case when the control signal is low or high,

respectively, and POS_MODE and NEG_MODE for positive and negative edges of the input signal. Setting

POS_MODE and NEG_MODE to 1 will increase the counter when an edge is detected, setting them to 2 will

decrease the counter and setting any other value will make the edge not have any effect on the counter.

LCTR_MODE and HCTR_MODE modify this behaviour as such when the control input has the corresponding low

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7.2 Functional Description 7 PULSE_CNT

or high value: 0 does not modify the NEG_MODE and POS_MODE behaviour, 1 inverts it (setting

POS_MODE/NEG_MODE to increase the counter will now decrease the counter and vice versa) and any other

value disables counter effects for that signal level.

To summarize, a few examples have been considered. In this table, the effect on the counter for a rising edge is

shown for both a low and a high control signal and various configuration options. For clarity, a short description in

brackets is added after the values. Note: x denotes ’don’t care’.

POS_ MODE LCTRL_ MODE HCTRL_ MODE sig l→h when ctrl=0 sig l→h when ctrl=1

1 (inc) 0 (-) 0 (-) Inc ctr Inc ctr

2 (dec) 0 (-) 0 (-) Dec ctr Dec ctr

0 (-) x x No action No action

1 (inc) 0 (-) 1 (inv) Inc ctr Dec ctr

1 (inc) 1 (inv) 0 (-) Dec ctr Inc ctr

2 (dec) 0 (-) 1 (inv) Dec ctr Inc ctr

1 (inc) 0 (-) 2 (dis) Inc ctr No action

1 (inc) 2 (dis) 0 (-) No action Inc ctr

This table is also valid for negative edges (sig h→l) on substituting NEG_MODE for POS_MODE.

Each pulse counter unit also features a filter on each of the four inputs, adding the option to ignore short glitches

in the signals. If a PCNT_FILTER_EN_Un can be set to filter the four input signals of the unit. If this filter is

enabled, any pulses shorter than REG_FILTER_THRES_Un number of APB_CLK clock cycles will be filtered out

and will have no effect on the counter. With the filter disabled, in theory infinitely small glitches could possibly

trigger pulse counter action. However, in practice the signal inputs are sampled on APB_CLK edges and even

with the filter disabled, pulse widths lasting shorter than one APB_CLK cycle may be missed.

Apart from the input channels, software also has some control over the counter. In particular, the counter value

can be frozen to the current value by configuring PCNT_CNT_PAUSE_Un. It can also be reset to zero by

configuring PCNT_PULSE_CNT_RST_Un.

7.2.3 Watchpoints

The pulse counters have 5 watchpoints that share one interrupt. Interrupt generation can be enabled or disabled

for each individual watchpoint. The watchpoints are:

• Maximum count value: Triggered when PULSE_CNT >= PCNT_THR_H_LIM_Un. Additionally, this will reset

the counter to zero.

• Minimum count value: Triggered when PULSE_CNT <= PCNT_THR_L_LIM_Un. Additionally, this will reset

the counter to zero. This is most useful when PCNT_THR_L_LIM_Un is set to a negative number.

• Two threshold values: Triggered when PULSE_CNT = PCNT_THR_THRES0_Un or

PCNT_THR_THRES1_Un.

• Zero: Triggered when PULSE_CNT = 0.

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7.3 Register Summary 7 PULSE_CNT

7.2.4 Examples

Figure 17: PULSE_CNT Upcounting Diagram

Figure 17 shows channel 0 being used as an up-counter. The configuration of channel 0 is shown below.

• CNT_CH0_POS_MODE_Un = 1: increase counter on the rising edge of sig_ch0_un.

• PCNT_CH0_NEG_MODE_Un = 0: no counting on the falling edge of sig_ch0_un.

• PCNT_CH0_LCTRL_MODE_Un = 0: Do not modify counter mode when sig_ch0_un is low.

• PCNT_CH0_HCTRL_MODE_Un = 2: Do not allow counter increments/decrements when sig_ch0_un is

high.

• PCNT_THR_H_LIM_Un = 5: PULSE_CNT resets to 0 when the count value increases to 5.

Figure 18: PULSE_CNT Downcounting Diagram

Figure 18 shows channel 0 decrementing the counter. The configuration of channel 0 differs from that in Figure

17 in the following two aspects:

• PCNT_CH0_LCTRL_MODE_Un = 1: invert counter mode when ctrl_ch0_un is at low level, so it will

decrease instead of increase the counter.

• PCNT_THR_H_LIM_Un = -5: PULSE_CNT resets to 0 when the count value decreases to -5.

7.2.5 Interrupts

PCNT_CNT_THR_EVENT_Un_INT: This interrupt gets triggered when one of the five channel comparators

detects a match.

7.3 Register Summary

Name Description Address Access

Configuration registers

PCNT_U0_CONF0_REG Configuration register 0 for unit 0 0x3FF57000 R/W

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7.3 Register Summary 7 PULSE_CNT

Name Description Address Access

PCNT_U1_CONF0_REG Configuration register 0 for unit 1 0x3FF5700C R/W

PCNT_U2_CONF0_REG Configuration register 0 for unit 2 0x3FF57018 R/W

PCNT_U3_CONF0_REG Configuration register 0 for unit 3 0x3FF57024 R/W

PCNT_U4_CONF0_REG Configuration register 0 for unit 4 0x3FF57030 R/W

PCNT_U5_CONF0_REG Configuration register 0 for unit 5 0x3FF5703C R/W

PCNT_U6_CONF0_REG Configuration register 0 for unit 6 0x3FF57048 R/W

PCNT_U7_CONF0_REG Configuration register 0 for unit 7 0x3FF57054 R/W

PCNT_U0_CONF1_REG Configuration register 1 for unit 0 0x3FF57004 R/W

PCNT_U1_CONF1_REG Configuration register 1 for unit 1 0x3FF57010 R/W

PCNT_U2_CONF1_REG Configuration register 1 for unit 2 0x3FF5701C R/W

PCNT_U3_CONF1_REG Configuration register 1 for unit 3 0x3FF57028 R/W

PCNT_U4_CONF1_REG Configuration register 1 for unit 4 0x3FF57034 R/W

PCNT_U5_CONF1_REG Configuration register 1 for unit 5 0x3FF57040 R/W

PCNT_U6_CONF1_REG Configuration register 1 for unit 6 0x3FF5704C R/W

PCNT_U7_CONF1_REG Configuration register 1 for unit 7 0x3FF57058 R/W

PCNT_U0_CONF2_REG Configuration register 2 for unit 0 0x3FF57008 R/W

PCNT_U1_CONF2_REG Configuration register 2 for unit 1 0x3FF57014 R/W

PCNT_U2_CONF2_REG Configuration register 2 for unit 2 0x3FF57020 R/W

PCNT_U3_CONF2_REG Configuration register 2 for unit 3 0x3FF5702C R/W

PCNT_U4_CONF2_REG Configuration register 2 for unit 4 0x3FF57038 R/W

PCNT_U5_CONF2_REG Configuration register 2 for unit 5 0x3FF57044 R/W

PCNT_U6_CONF2_REG Configuration register 2 for unit 6 0x3FF57050 R/W

PCNT_U7_CONF2_REG Configuration register 2 for unit 7 0x3FF5705C R/W

Counter values

PCNT_U0_CNT_REG Counter value for unit 0 0x3FF57060 RO

PCNT_U1_CNT_REG Counter value for unit 1 0x3FF57064 RO

PCNT_U2_CNT_REG Counter value for unit 2 0x3FF57068 RO

PCNT_U3_CNT_REG Counter value for unit 3 0x3FF5706C RO

PCNT_U4_CNT_REG Counter value for unit 4 0x3FF57070 RO

PCNT_U5_CNT_REG Counter value for unit 5 0x3FF57074 RO

PCNT_U6_CNT_REG Counter value for unit 6 0x3FF57078 RO

PCNT_U7_CNT_REG Counter value for unit 7 0x3FF5707C RO

Control registers

PCNT_CTRL_REG Control register for all counters 0x3FF570B0 R/W

Interrupt registers

PCNT_INT_RAW_REG Raw interrupt status 0x3FF57080 RO

PCNT_INT_ST_REG Masked interrupt status 0x3FF57084 RO

PCNT_INT_ENA_REG Interrupt enable bits 0x3FF57088 R/W

PCNT_INT_CLR_REG Interrupt clear bits 0x3FF5708C WO

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7.4 Registers 7 PULSE_CNT

7.4 Registers

PCNT_CH1_NEG_MODE_Un

PCNT_CH1_POS_MODE_Un

PCNT_CH1_HCTRL_MODE_Un

PCNT_CH1_LCTRL_MODE_Un

31 30

29 28

27 26

PCNT_CH0_HCTRL_MODE_Un

PCNT_CH0_LCTRL_MODE_Un

25 24

23 22

21 20

19 18

PCNT_CH0_NEG_MODE_Un

PCNT_CH0_POS_MODE_Un

17 16

PCNT_THR_THRES1_EN_Un

PCNT_THR_L_LIM_EN_Un

PCNT_THR_THRES0_EN_Un

PCNT_CH1_LCTRL_MODE_Un This register configures how the CH1_POS_MODE/CH1_NEG_MODE

settings will be modified when the control signal is low. (R/W) 0: No modification; 1: Invert behaviour

(increase -> decrease, decrease -> increase); 2, 3: Inhibit counter modification

PCNT_CH1_HCTRL_MODE_Un This register configures how the CH1_POS_MODE/CH1_NEG_MODE

settings will be modified when the control signal is low. (R/W) 0: No modification; 1: Invert behaviour

(increase -> decrease, decrease -> increase); 2, 3: Inhibit counter modification

PCNT_FILTER_EN_Un

PCNT_THR_ZERO_EN_Un

PCNT_THR_H_LIM_EN_Un

9 0

PCNT_FILTER_THRES_Un

0x010

Reset

PCNT_CH1_POS_MODE_Un This register sets the behaviour when the signal input of channel 1 detects a

positive edge. (R/W) 1: Increment the counter; 2: Decrement the counter; 0, 3: No effect on counter

PCNT_CH1_NEG_MODE_Un This register sets the behaviour when the signal input of channel 1 detects a

negative edge. (R/W) 1: Increment the counter; 2: Decrement the counter; 0, 3: No effect on counter

PCNT_CH0_LCTRL_MODE_Un This register configures how the CH0_POS_MODE/CH0_NEG_MODE

settings will be modified when the control signal is low. (R/W) 0: No modification; 1: Invert behaviour

(increase -> decrease, decrease -> increase); 2, 3: Inhibit counter modification

PCNT_CH0_HCTRL_MODE_Un This register configures how the CH0_POS_MODE/CH0_NEG_MODE

settings will be modified when the control signal is low. (R/W) 0: No modification; 1: Invert behaviour

(increase -> decrease, decrease -> increase); 2, 3: Inhibit counter modification

PCNT_CH0_POS_MODE_Un This register sets the behaviour when the signal input of channel 0 detects a

positive edge. (R/W) 1: Increase the counter; 2: Decrease the counter; 0, 3: No effect on counter

PCNT_CH0_NEG_MODE_Un This register sets the behaviour when the signal input of channel 0 detects a

negative edge. (R/W) 1: Increase the counter; 2: Decrease the counter; 0, 3: No effect on counter

PCNT_THR_THRES1_EN_Un This is the enable bit for unit n’s thres1 comparator. (R/W)

PCNT_THR_THRES0_EN_Un This is the enable bit for unit n’s thres0 comparator. (R/W)

PCNT_THR_L_LIM_EN_Un This is the enable bit for unit n’s thr_l_lim comparator. (R/W)

PCNT_THR_H_LIM_EN_Un This is the enable bit for unit n’s thr_h_lim comparator. (R/W)

PCNT_THR_ZERO_EN_Un This is the enable bit for unit n’s zero comparator. (R/W)

PCNT_FILTER_EN_Un This is the enable bit for unit n’s input filter. (R/W)

PCNT_FILTER_THRES_Un This sets the maximum threshold, in APB_CLK cycles, for the filter. Any pulses

lasting shorter than this will be ignored when the filter is enabled. (R/W)

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7.4 Registers 7 PULSE_CNT

PCNT_CNT_THRES1_Un

31 16

0x000

15 0

PCNT_CNT_THRES0_Un

0x000

PCNT_CNT_THRES1_Un This register is used to configure the thres1 value for unit n. (R/W)

PCNT_CNT_THRES0_Un This register is used to configure the thres0 value for unit n. (R/W)

PCNT_CNT_L_LIM_Un

31 16

0x000

15 0

PCNT_CNT_H_LIM_Un

0x000

PCNT_CNT_L_LIM_Un This register is used to configure the thr_l_lim value for unit n. (R/W)

PCNT_CNT_H_LIM_Un This register is used to configure the thr_h_lim value for unit n. (R/W)

Reset

(reserved)

31 16

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

15 0

PCNT_PLUS_CNT_Un

0x00000

PCNT_PLUS_CNT_Un This register stores the current pulse count value for unit n. (RO)

Reset

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7.4 Registers 7 PULSE_CNT

(reserved)

31 8

0x0000000

PCNT_CNT_THR_EVENT_U7_INT_RAW

PCNT_CNT_THR_EVENT_U4_INT_RAW

PCNT_CNT_THR_EVENT_U5_INT_RAW

PCNT_CNT_THR_EVENT_U6_INT_RAW

PCNT_CNT_THR_EVENT_U1_INT_RAW

PCNT_CNT_THR_EVENT_U2_INT_RAW

PCNT_CNT_THR_EVENT_U3_INT_RAW

PCNT_CNT_THR_EVENT_Un_INT_RAW The raw interrupt status bit for the

PCNT_CNT_THR_EVENT_Un_INT interrupt. (RO)

(reserved)

31 8

0x0000000

PCNT_CNT_THR_EVENT_U7_INT_ST

PCNT_CNT_THR_EVENT_U4_INT_ST

PCNT_CNT_THR_EVENT_U5_INT_ST

PCNT_CNT_THR_EVENT_U6_INT_ST

PCNT_CNT_THR_EVENT_U1_INT_ST

PCNT_CNT_THR_EVENT_U2_INT_ST

PCNT_CNT_THR_EVENT_U3_INT_ST

PCNT_CNT_THR_EVENT_Un_INT_ST The masked interrupt status bit for the

PCNT_CNT_THR_EVENT_Un_INT interrupt. (RO)

PCNT_CNT_THR_EVENT_U0_INT_RAW

Reset

PCNT_CNT_THR_EVENT_U0_INT_ST

Reset

(reserved)

31 8

0x0000000

PCNT_CNT_THR_EVENT_U7_INT_ENA

PCNT_CNT_THR_EVENT_U3_INT_ENA

PCNT_CNT_THR_EVENT_U4_INT_ENA

PCNT_CNT_THR_EVENT_U5_INT_ENA

PCNT_CNT_THR_EVENT_U6_INT_ENA

PCNT_CNT_THR_EVENT_U0_INT_ENA

PCNT_CNT_THR_EVENT_U1_INT_ENA

PCNT_CNT_THR_EVENT_U2_INT_ENA

Reset

PCNT_CNT_THR_EVENT_Un_INT_ENA The interrupt enable bit for the

PCNT_CNT_THR_EVENT_Un_INT interrupt. (R/W)

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7.4 Registers 7 PULSE_CNT

(reserved)

31 8

0x0000000

PCNT_CNT_THR_EVENT_U7_INT_CLR

PCNT_CNT_THR_EVENT_U4_INT_CLR

PCNT_CNT_THR_EVENT_U5_INT_CLR

PCNT_CNT_THR_EVENT_U6_INT_CLR

PCNT_CNT_THR_EVENT_U1_INT_CLR

PCNT_CNT_THR_EVENT_U2_INT_CLR

PCNT_CNT_THR_EVENT_U3_INT_CLR

PCNT_CNT_THR_EVENT_Un_INT_CLR Set this bit to clear the PCNT_CNT_THR_EVENT_Un_INT

interrupt. (WO)

(reserved)

31 17

0x0000

(reserved)

PCNT_CNT_PAUSE_U6

PCNT_PLUS_CNT_RST_U7

PCNT_CNT_PAUSE_U7

PCNT_CNT_PAUSE_U4

PCNT_PLUS_CNT_RST_U5

PCNT_CNT_PAUSE_U5

PCNT_PLUS_CNT_RST_U6

PCNT_PLUS_CNT_RST_U3

PCNT_CNT_PAUSE_U3

PCNT_PLUS_CNT_RST_U4

PCNT_CNT_PAUSE_U0

PCNT_PLUS_CNT_RST_U1

PCNT_PLUS_CNT_RST_U2

PCNT_CNT_PAUSE_U2

PCNT_CNT_PAUSE_U1

PCNT_CNT_PAUSE_Un Set this bit to freeze unit n’s counter. (R/W)

PCNT_PLUS_CNT_RST_Un Set this bit to clear unit n’s counter. (R/W)

PCNT_CNT_THR_EVENT_U0_INT_CLR

Reset

PCNT_PLUS_CNT_RST_U0

Reset

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8 64-BIT TIMERS

8. 64-bit Timers

8.1 Introduction

There are four general-purpose timers embedded in the ESP32. They are all 64-bit generic timers based on

16-bit prescalers and 64-bit auto-reload-capable up/downcounters.

The ESP32 contains two timer modules, each containing two timers. The two timers in a block are indicated by

an x in TIMGn_Tx; the blocks themselves are indicated by an n.

The timers feature:

• A 16-bit clock prescaler, from 2 to 65536

• A 64-bit time-base counter

• Configurable up/down time-base counter: incrementing or decrementing

• Halt and resume of time-base counter

• Auto-reload at alarm

• Software-controlled instant reload

• Level and edge interrupt generation

8.2 Functional Description

8.2.1 16-bit Prescaler

Each timer uses the APB clock (APB_CLK, normally 80 MHz) as the basic clock. This clock is then divided down

by a 16-bit precaler which generates the time-base counter clock (TB_clk). Every cycle of TB_clk causes the

time-base counter to increment or decrement by one. The timer must be disabled (TIMGn_Tx_EN is cleared)

before changing the prescaler divisor which is configured by TIMGn_Tx_DIVIDER register; changing it on an

enabled timer can lead to unpredictable results. The prescaler can divide the APB clock by a factor from 2 to

65536. Specifically, when TIMGn_Tx_DIVIDER is either 1 or 2, the clock divisor is 2; when TIMGn_Tx_DIVIDER is

0, the clock divisor is 65536. Any other value will cause the clock to be divided by exactly that value.

8.2.2 64-bit Time-base Counter

The 64-bit time-base counter can be configured to count either up or down, dependent on whether

TIMGn_Tx_INCREASE is set or cleared, respectively. It supports both auto-reload and software instant reload.

An alarm event can be set to trigger when the counter reaches a value specified by software.

Counting can be enabled and disabled by setting and clearing TIMGn_Tx_EN. Clearing this bit essentially freezes

the counter, causing it to neither count up nor count down, but instead retain its value until TIMGn_Tx_EN is set

again. Reloading the counter when TIMGn_Tx_EN is cleared will change its value, but counting will not be

resumed until TIMGn_Tx_EN is set.

Software can set a new counter value by setting registers TIMGn_Tx_LOAD_LO and TIMGn_Tx_LOAD_HI to the

intended new value. The hardware will ignore these register settings until a reload; a reload will cause the

contents of these registers to be copied to the counter itself. A reload event can be triggered by an alarm

(auto-reload at alarm) or by software (software instant reload). To enable auto-reload at alarm, the register

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8.3 Register summary 8 64-BIT TIMERS

TIMGn_Tx_AUTORELOAD should be set. If auto-reload at alarm is not enabled, the time-base counter will

continue incrementing or decrementing after the alarm. To trigger a software instant reload, any value can be

written to the register TIMGn_Tx_LOAD_REG; this will cause the counter value to change instantaneously.

Software can also change the direction of the time-base counter instantaneously by changing the value of

TIMGn_Tx_INCREASE.

The time-base counter can also be read by software, but because the counter is 64-bit, the CPU can only get the

value as two 32-bit values, the counter value needs to be latched into TIMGn_TxLO_REG and TIMGn_TxHI_REG

first. This is done by writing any value to TIMGn_TxUPDATE_REG; this will instantly latch the 64-bit timer value to

the two registers. Software can then read them at any point of time. This approach stops the timer value being

read erroneously when a carry-over happens between reading the low and high word of the timer value.

8.2.3 Alarm Generation

The timer can trigger an alarm, which can cause a reload and/or an interrupt to trigger. The alarm triggers when

the alarm registers TIMGn_Tx_ALARMLO_REG and TIMGn_Tx_ALARMHI_REG match the current timer value. In

order to simplify the scenario where these registers are set ’too late’ and the counter already passed these

values, the alarm also triggers when the current timer value is higher (for an up-counting timer) or lower (for a

down-counting timer) than the current alarm value: if this is the case, the alarm will be triggered immediately upon

loading the alarm registers.

8.2.4 MWDT

Each timer module also contains a Main System Watchdog Timer and associated registers. While the registers

are described here, the functional description can be found in the Chapter Watchdog Timer.

8.2.5 Interrupts

• TIMGn_Tx_INT_WDT_INT: Generated when a watchdog timer interrupt stage times out.

• TIMGn_Tx_INT_T1_INT: An alarm event on timer 1 generates this interrupt.

• TIMGn_Tx_INT_T0_INT: An alarm event on timer 0 generates this interrupt.

8.3 Register summary

Name Description TIMG0 TIMG1 Acc

Timer 0 configuration and control registers

TIMGn_T0CONFIG_REG Timer 0 configuration register 0x3FF5F000 0x3FF60000 R/W

TIMGn_T0LO_REG Timer 0 current value, low 32 bits 0x3FF5F004 0x3FF60004 RO

TIMGn_T0HI_REG Timer 0 current value, high 32 bits 0x3FF5F008 0x3FF60008 RO

TIMGn_T0UPDATE_REG

TIMGn_T0ALARMLO_REG Timer 0 alarm value, low 32 bits 0x3FF5F010 0x3FF60010 R/W

TIMGn_T0ALARMHI_REG Timer 0 alarm value, high bits 0x3FF5F014 0x3FF60014 R/W

TIMGn_T0LOADLO_REG Timer 0 reload value, low 32 bits 0x3FF5F018 0x3FF60018 R/W

TIMGn_T0LOAD_REG

Write to copy current timer value to

TIMGn_T0_(LO/HI)_REG

Write to reload timer from

TIMGn_T0_(LOADLOLOADHI)_REG

0x3FF5F00C 0x3FF6000C WO

0x3FF5F020 0x3FF60020 WO

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Espressif Systems ESP32 Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

1. System and Memory

1.1 Introduction

1.2 Features

1.3.1 Address Mapping

1.3.2 Embedded Memory

1.3.3 External Memory

1.3.4 Peripherals

2. Interrupt Matrix

2.1 Introduction

2.2 Features

2.3 Functional Description

2.3.1 Peripheral Interrupt Source

2.3.2 CPU Interrupt

2.3.3 Allocate Peripheral Interrupt Sources to Peripheral Interrupt on CPU

2.3.4 CPU NMI Interrupt Mask

2.3.5 Query Current Interrupt Status of Peripheral Interrupt Source

3. Reset and Clock

3.1 System Reset

3.1.1 Introduction

3.1.2 Reset Source

3.2 System Clock

3.2.1 Introduction

3.2.2 Clock Source

3.2.3 CPU Clock

3.2.4 Peripheral Clock

3.2.5 Wi-Fi BT Clock

3.2.6 RTC Clock

4. IO_MUX and GPIO Matrix

4.1 Introduction

4.2 Peripheral Input via GPIO Matrix

4.2.1 Summary

4.2.2 Functional Description

4.2.3 Simple GPIO Input

4.3 Peripheral Output via GPIO Matrix

4.3.1 Summary

4.3.2 Functional Description

4.3.3 Simple GPIO Output

4.4 Direct I/O via IO_MUX

4.4.1 Summary

4.4.2 Functional Description

4.5 RTC IO_MUX for Low Power and Analog I/O

4.5.1 Summary

4.5.2 Functional Description

4.6 Light-sleep Mode Pin Functions

4.7 Pad Hold Feature

4.8 I/O Pad Power Supply

4.8.1 VDD_SDIO Power Domain

4.9 Peripheral Signal List

4.10 IO_MUX Pad List

4.11 RTC_MUX Pin List

4.12 Register Summary

4.13 Registers

5. LED_PWM

5.1 Introduction

5.2 Functional Description

5.2.1 Architecture

5.2.2 Timers

5.2.3 Channels

5.2.4 Interrupts

5.3 Register Summary

5.4 Registers

6. Remote Controller Peripheral

6.1 Introduction

6.2 Functional Description

6.2.1 RMT Architecture

6.2.2 RMT RAM

6.2.3 Clock

6.2.4 Transmitter

6.2.5 Receiver

6.2.6 Interrupts

6.4 Registers

7. PULSE_CNT

7.1 Introduction

7.2 Functional Description

7.2.1 Architecture

7.2.2 Counter Channel Inputs