• Low-cost solution for low-speed applications with high
I/O requirements such as keyboards, keyboards with
integrated pointing device, gamepads, and many
others
• USB Specification Compliance
— Conforms to USB Specification, V ersions 1.1 and 2.0
— Conforms to USB HID Specification, Version 1.1
— Supp orts 1 device address and 3 data endpoints
— Integrated USB transceiver
• Internal memory
— 256 bytes of RAM
— 8 Kbytes of EPROM
• Interface can auto-configure to operate as PS2 or USB
•I/O port
— The CY7C63413C/513C have 24 General Purpose I/O
(GPIO) pins (Port 0 to 2) cap able of sinking 7 mA per
pin (typical)
— The CY7C63613C has 12 General Purpose I/O (GPIO)
pins (Port 0 to 2) capable of sinking 7 mA per pin
(typical)
— The CY7C63413C/513C have eight GPIO pins (Port
3) capable of sinking 12 mA per pin (typical) which
can drive LEDs
— The CY7C63613C has four GPIO pins (Port 3) capable
of sinking 12 mA per pin (typical) which can driv e
LEDs
— Higher current drive is available by connecting
multiple GPIO pins together to drive a common
output
— Each GPIO port can be configured as inputs with
internal pull-ups or open drain outputs or traditional
CMOS outputs
— The CY7C63513C has an additional eight I/O pins on
a DAC port which has programmable current sink
outputs
— Mask able interrupts on all I/O pins
• 12-bit free-running timer with one microsecond clock
ticks
• Watch Dog Timer (WDT)
• Internal Power-On Reset (POR)
• Improved output drivers to reduce EMI
• Operating voltage from 4.0V to 5.5V DC
• Operating temperature from 0 to 70 degrees Celsius
• CY7C63413C available in 40-pin PDIP , 48-pin SSOP, 48pin SSOP - Tape reel, all in Lead-Free versions for
production
• CY7C63513C available in 48-pin SSOP Lead-Free
packages for production
• CY7C63613C available in 24-pin SOIC Lead-Free
packages for production
• Industry-standard programmer support
Functional Overview
The CY7C63413C/513C/613C are 8-bit RISC One Time
Programmable (OTP) microcontrollers. The instruction set has
been optimized specifically for USB operations, although the
microcontrollers can be used for a variety of non-USB
embedded applications.
The CY7C63413C/513C features 32 General-Purpose I/O
(GPIO) pins to support USB and other applications. The I/O
pins are grouped into four ports (Port 0 to 3) where each port
can be configured as inputs with internal pull -ups, open drain
outputs, or traditional CMOS outputs. The CY7C63413C/513C
have 24 GPIO pins (Ports 0 to 2) that are rated at 7 mA typical
sink current. The CY7C63413C/513C has 8 GPIO pins (Port
3) that are rated at 12 mA typical sink current, which allows
these pins to drive LEDs.
The CY7C63613C features 16 General-Purpose I/O (GPIO)
pins to support USB and other applications. The I/O pins are
grouped into four ports (Port 0 to 3) where each port can be
configured as inputs with internal pull-ups, open drain outputs,
or traditional CMOS outputs. The CY7C63613C has 12 GPIO
pins (Ports 0 to 2) that are rated at 7 mA typical sink current.
The CY7C63613C has 4 GPIO pins (Port 3) that are rated at
12 mA typical sink current, which allows these pins to drive
LEDs.
Multiple GPIO pins can be connected together to drive a single
output for more dri ve current capacity. Additionally, each I/O
pin can be used to generate a GPIO interrupt to the microcontroller. Note the GPIO interrupts all share the same “GPIO”
interrupt vector.
The CY7C63513C features an additional 8 I/O pins in the DAC
port. Every DAC pin includes an integrated 14-Kohm pull-up
resistor. When a “1” is written to a DAC I/O pin, the output
current sink is disabled and the output pin is driven high by the
internal pull-up resistor. When a “0” is written to a DAC I/O pin,
the internal pull-up is disabled and the output pin provides the
programmed amount of sink
current. A DAC I/O pin can
be used as an input with an
internal pull-up by writing a
“1” to the pin.
Cypress Semiconductor Corporation•198 Champion Court•San Jose, CA 95134-1709•408-943-2600
Document #: 38-08027 Rev. *B Revised January 6, 2006
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CY7C63413C
CY7C63513C
CY7C63613C
The sink current for each DAC I/O pin can be individually
programmed to one of sixteen values using dedicated Isink
registers. DAC bits [1:0] can be used as high current outputs
with a programmable sink current range of 3.2 to 16 mA
(typical). DAC bits [7:2] have a programmable current sink
range of 0.2 to 1.0 mA (typical). Again, multiple DAC pins can
be connected together to drive a single output that requires
more sink current capacity. Each I/O pin can be used to
generate a DAC interrupt to the microcontroller and the
interrupt polarity for each DAC I/O pin is individually programmable. The DAC port interrupts share a separate “DAC”
interrupt vector.
The Cypress microcontrollers use an external 6-MHz ceramic
resonator to provide a reference to an internal clock generator.
This clock generator reduces the clock-related noise
emissions (EMI). The clock generator provide s the 6 a nd 12MHz clocks that remain internal to the microcontroller.
The CY7C63413C/513C/613C are offered with single EPROM
options. The CY7C63413C, CY7C63513C and the
CY7C63613C have 8 Kbytes of EPROM.
These parts include Power-on Reset logic, a Watch Dog Timer ,
a vectored interrupt controller, and a 12-bit free-running timer.
The Power-On Reset (POR) logic detects when power is
applied to the device, resets the logic to a known state, and
begins executing instructions at EPROM address 0x0000. The
Watch Dog Timer can be used to ensure the firmware never
gets stalled for more than approximately 8 ms. The firmware
can get stalled for a variety of reasons, including errors in the
code or a hardware failure such as waiting for an interrupt that
never occurs. The firmware should clear the Watch Dog Timer
periodically. If the Watch Dog Timer is not cleared for approximately 8 ms, the microcontroller will generate a hardware
watch dog reset.
The microcontroller supports eight maskable interrupts in the
vectored interrupt controller. Interrupt sources include the USB
Bus-Reset, the 128-µs and 1.024-ms outputs from the freerunning timer, three USB endpoints, the DAC port, and the
GPIO ports. The timer bits cause an interrupt (if enabled) when
the bit toggles from LOW “0” to HIGH “1.” The USB endpoints
interrupt after either the USB host or the USB controller sends
a packet to the USB. The DAC ports have an additional level
of masking that allows the user to select which DAC inputs can
cause a DAC interrupt. The GPIO ports also have a level of
masking to select which GPIO inputs can cause a GPIO
interrupt. For additional flexibility, the input transition polarity
that causes an interrupt is programmable for each pin of the
DAC port. Input transition polarity can be programmed for
each GPIO port as part of the port configuration. The interrupt
polarity can be either rising edge (“0” to “1”) or falling edge (“1”
to “0”).
The free-running 12-bit timer clocked at 1 MHz provides two
interrupt sources as noted above (128-µs and 1.024-ms). The
timer can be used to measure the duration of an event under
firmware control by reading the timer twice: once at the start
of the event, and once after the event is complete. The
difference between the two readings indicates the durati on of
the event measured in microseconds. The upper four bits of
the timer are latched into an internal register when the
firmware reads the lower eight bits. A read from the upper four
bits actually reads data from the internal register, instead of the
timer. This feature eliminates the need for firmware to attempt
to compensate if the upper four bits happened to incre ment
right after the lower 8 bits are read.
The CY7C63413C/513C/613C include an integrated USB
serial interface engine (SIE) that supports the integrated
peripherals. The hardware supports one USB device address
with three endpoints. The SIE allows the USB host to communicate with the function integrated into the microcontroller.
Finally, the CY7C63413C/513C/613C support PS/2 operation.
With appropriate firmware the D+ and D– USB pins can also
be used as PS/2 clock and data signals. Products utilizing
these devices can be used for USB and/or PS/2 operation with
appropriate firmware.
1. CY7C63613C is not bonded out for all GPIO pins shown in Logic Block Diagram. Refer to pin configuration diagram for bonded out pins. See note on page 12
for firmware code needed for unused GPIO pins.
.
Document #: 38-08027 Rev. *BPage 3 of 32
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CY7C63413C
CY7C63513C
CY7C63613C
Pin Definitions
CY7C63413CCY7C63513C CY7C63613C
NameI/O
D+, D–I/O1,21,21,21,21,2USB differential data; PS/2 clock and
P0[7:0]I/O15,26,16
25,17,24
18,23
P1[3:0]I/O11,30,12,
P2I/O7,34,8,
P3[7:4]I/O3,38,4,
DACI/On/an/a15,34,16,
XTAL
IN
XTAL
OUT
V
PP
V
CC
Vss20,3924,4724,4724,4712, 23Ground
29,13,28,
14,27
33,9,32,
10,31
37,5,36,
6,35
21252525136-MHz ceramic resonator or external
IN
OUT22262626146-MHz ceramic resonator
1923232311Programming voltage supply, ground
4048484824Voltage supply
17,32,18
31,19,30
20,29
11,38,12,
37,13,36,
14,35
7,42,8,
41,9,40,
10,39
3,46,4,
45,5,44,
6,43
17,32,18,
31,19,30,
20,29
1 1,38,12,
37,13,36,
14,35
7,42,8,
41,9,40,
10,39
3,46,4,
45,5,44,
6,43
33,21,28,
22,27
17,32,18,31,
19,30,20,29
1 1,38,12,37,
13,36,14,35
7,42,8,41,9,
40,10,39
3,46,4,45,5,
44,6,43
15,34,16,33,
21,28,22,27
7, 18, 8, 17, 9,
16, 10, 15
5, 20, 6, 19GPIO Port 1 capable of sinking 7 mA
n/aGPIO Port 2 capable of sinking 7 mA
3, 22, 4, 21GPIO Port 3 capable of sinking 12 mA
n/aDAC I/O Port with programmable
Description40-Pin48-PinDie48-Pin24-Pin
data signals
GPIO port 0 capable of sinking 7 mA
(typical)
(typical).
(typical).
(typical).
current sink outputs. DAC[1:0] offer a
programmable range of 3.2 to 16 mA
typical. DAC[7:2] have a programmable sink current range of 0.2 to 1.0
mA typical. DAC I/O Port not bonded
out on CY7C63613C. See note on
page 12 for firmware code needed for
unused pins.
clock input
during operation
Programming Model
14-bit Program Counter (PC)
The 14-bit Program Counter (PC) allows access for up to 8
kilobytes of EPROM using the CY7C63413C/513C/613C
architecture. The program counter is cleared during reset,
such that the first instruction executed after a reset is at
address 0x0000. This is typically a jump instruction to a reset
handler that initializes the application.
The lower eight bits of the program counter are incremented
as instructions are loaded and executed. The upper six bits of
the program counter are incremented by executing an XPAGE
instruction. As a result, the last instruction executed within a
256-byte “page” of sequential code should be an XPAGE
instruction. The assembler directive “XPAGEON” will cause
the assembler to insert XPAGE instructions automatically. As
instructions can be either one or two bytes long, the assembler
may occasionally need to insert a NOP followed by an XPAGE
for correct execution.
The program counter of the next instruction to be executed,
carry flag, and zero flag are saved as two bytes on the program
stack during an interrupt acknowledge or a CALL instruction.
The program counter, carry flag, and zero flag are restored
from the program stack only during a RETI instruction.
Document #: 38-08027 Rev. *BPage 4 of 32
Please note the program counter cannot be accessed directly
by the firmware. The program stack can be examined by
reading SRAM from location 0x00 and up.
8-bit Accumulator (A)
The accumulator is the general purpose, do everything
register in the architecture where results are usually calculated.
8-bit Index Register (X)
The index register “X” is available to the firmware as an
auxiliary accumulator. The X register also allows the processor
to perform indexed operations by loading an index value into
X.
8-bit Program Stack Pointer (PSP)
During a reset, the Program Stack Pointer (PSP) is set to zero.
This means the program “stack” starts at RAM address 0x00
and “grows” upward from there. Note the program stack
pointer is directly addressable under firmware con trol, using
the MOV PSP,A instruction. The PSP supports interrupt
service under hardware control and CALL, RET, and RETI
instructions under firmware control.
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CY7C63513C
CY7C63613C
During an interrupt acknowledge, interrupts are disabled and
the 14-bit program counter, carry flag, and zero flag are written
as two bytes of data memory. The first byte is stored in the
memory addressed by the program stack pointer, then the
PSP is incremented. The second byte is stored in memory
addressed by the program stack pointer and the PSP is incremented again. The net effect is to store the program counter
and flags on the program “stack” and increment the program
stack pointer by two.
The Return From Interrupt (RETI) instruction decrements the
program stack pointer, then restores the second byte from
memory addressed by the PSP. The program stack pointer is
decremented again and the first byte is restored from memory
addressed by the PSP. After the program counter and flags
have been restored from stack, the interrupts are enabled. The
effect is to restore the program counter and flags from the
program stack, decrement the program stack pointer by two,
and re-enable interrupts.
The Call Subroutine (CALL) instruction stores the program
counter and flags on the program stack and increments the
PSP by two.
The Return From Subroutine (RET) instruction restores the
program counter, but not the flags, from program stack and
decrements the PSP by two.
8-bit Data Stack Pointer (DSP)
The Data Stack Pointer (DSP) supports PUSH and POP
instructions that use the data stack for temporary storage. A
PUSH instruction will pre-decrement the DSP, then write data
to the memory location addressed by the DSP. A POP
instruction will read data from the memory location addressed
by the DSP, then post-incre ment the DSP.
During a reset, the Data Stack Pointer will be set to zero. A
PUSH instruction when DSP equal zero will write data at the
top of the data RAM (address 0xFF). This would write data to
the memory area reserved for a FIFO for USB endpoint 0. In
non-USB applications, this works fine and is not a problem.
For USB applications, it is strongly recommended that the
DSP is loaded after reset just below the USB DMA buffers.
Address Modes
The CY7C63413C/513C/613C microcontrollers support three
addressing modes for instructions that require data operands:
data, direct, and indexed.
Data
The “Data” address mode refers to a data operand that is
actually a constant encoded in the instruction. As an example,
consider the instruction that loads A with the constant 0xE8:
• MOV A,0E8h
This instruction will require two bytes of code where the first
byte identifies the “MOV A” instruction with a data operand as
the second byte. The second byte of the ins truction will be the
constant “0xE8”. A constant may be referred to by name if a
prior “EQU” statement assigns the constant value to the name.
For example, the following code is equivalent to the example
shown above:
• DSPINIT: EQU 0E8h
• MOV A,DSPINIT
Direct
“Direct” address mode is used when the data operand is a
variable stored in SRAM. In that case, the one byte address of
the variable is encoded in the instruction. As an example,
consider an instruction that loads A with the contents of
memory address location 0x10:
• MOV A, [10h]
In normal usage, variable names are assigned to variable
addresses using “EQU” statements to improve the readability
of the assembler source code. As an example, the following
code is equivalent to the example shown above:
• buttons: EQU 10h
• MOV A,[buttons]
Indexed
“Indexed” address mode allows the firmware to manipulate
arrays of data stored in SRAM. The address of the data
operand is the sum of a constant encoded in the instruction
and the contents of the “X” register. In normal usage, the
constant will be the “base” address of an array of data and the
X register will contain an index that indicates which element of
the array is actually addressed:
• array: EQU 10h
•MOV X,3
• MOV A,[x+array]
This would have the effect of loading A with the fourth element
of the SRAM “array” that begins at address 0x10. The fourth
element would be at address 0x13.
HALT 007
ADD A,expr data014INC Aacc214
ADD A,[expr] direct026
ADD A,[X+expr] index037INC [expr]direct237
ADC A,exprdata044
ADC A,[expr]direct056
ADC A,[X+expr]index067DEC Xx264
SUB A,exprdata074
SUB A,[expr]direct086
SUB A,[X+expr]index097IORD expraddress295
SBB A,exprdata0A4
SBB A,[expr]direct0B6
SBB A,[X+expr]index0C7
OR A,exprdata0D4
OR A,[expr]direct0E6
OR A,[X+expr]index0F7SWAP A,X2F5
AND A,exprdata104
AND A,[expr]direct116
AND A,[X+expr]index127MOV [X+expr],Aindex326
XOR A,exprdata134
XOR A,[expr]direct146
XOR A,[X+expr]index157AND [expr],Adirect357
CMP A,exprdata165
CMP A,[expr]direct177
CMP A,[X+expr]index188XOR [X+expr] ,Aindex388
MOV A,exprdata194
MOV A,[expr]direct1A5
MOV A,[X+expr]index1B6ASL3B4
MOV X,exprdata1C4
MOV X,[expr]direct1D5
reserved1E
XPAGE1F4
MOV A,X404
MOV X,A414
MOV PSP,A604
CALLaddr50-5F10
JMPaddr80-8F5JCaddrC0-CF5
CALLaddr90-9F10
JZaddrA0-AF5JACCaddrE0-EF7
JNZaddrB0-BF5
NOP204
INC Xx224
INC [X+expr]index248
DEC Aacc254
DEC [expr]direct277
DEC [X+expr]index288
IOWR expraddress2A5
POP A2B4
POP X2C4
PUSH A2D5
PUSH X2E5
SWAP A,DSP305
MOV [expr],Adirect315
OR [expr],Adirect337
OR [X+expr],Aindex348
AND [X+expr],Aindex368
XOR [expr],Adirect377
IOWX [X+expr]index396
CPL3A4
ASR3C4
RLC3D4
RRC 3E4
RET 3F8
DI704
EI724
RETI738
JNCaddrD0-DF5
INDEXaddrF0-FF14
Document #: 38-08027 Rev. *BPage 6 of 32
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Memory Organization
Program Memory Organization
after resetAddress
14-bit PC0x0000Program execution begins here after a reset
0x0002USB Bus Reset interrupt vector
0x0004128-µs timer interrupt vector
0x00061.024-ms timer interrupt vector
0x0008USB address A endpoint 0 interrupt vector
0x000AUSB address A endpoint 1 interrupt vector
0x000CUSB address A endpoint 2 interrupt vector
0x000EReserved
CY7C63413C
CY7C63513C
CY7C63613C
0x0010Reserved
0x0012Reserved
0x0014DAC interrupt vector
0x0016GPIO interrupt vector
0x0018Reserved
0x001AProgram Memory begins here
(8K - 32 bytes)
0x1FDF8-KB PROM ends here (CY7C63413C, CY7C63513C, CY7C63613C)
Figure 1. Program Memory Space with Interrupt Vector Table
Document #: 38-08027 Rev. *BPage 7 of 32
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CY7C63413C
CY7C63513C
CY7C63613C
Data Memory Organization
The CY7C63413C/513C/613C microcontrollers provide 256
bytes of data RAM. In normal usage, the SRAM is partitioned
after resetAddress
8-bit PSP0x00Program Stack begins here and grows upward
8-bit DSPuserData Stack begins here and grows downward
The user determines the amount of memory required
User Variables
0xE8
USB FIFO for Address A endpoint 2
0xF0
USB FIFO for Address A endpoint 1
0xF8
USB FIFO for Address A endpoint 0
Top of RAM Memory0xFF
into four areas: program stack, data stack, user variables and
USB endpoint FIFOs as shown below:
Document #: 38-08027 Rev. *BPage 8 of 32
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CY7C63413C
CY7C63513C
CY7C63613C
I/O Register Summary
I/O registers are accessed via the I/O Read (IORD) and I/O
Write (IOWR, IOWX) instructions. IORD reads the selected
port into the accumulator. IOWR writes data from the accumu-
Table 1. I/O Register Summary
Register NameI/O AddressRead/WriteFunction
Port 0 Data0x00R/WGPIO Port 0
Port 1 Data0x01R/WGPIO Port 1
Port 2 Data0x02R/WGPIO Port 2
Port 3 Data0x03R/WGPIO Port 3
Port 0 Interrupt Enable0x04WInterrupt enable for pins in Port 0
Port 1 Interrupt Enable0x05WInterrupt enable for pins in Port 1
Port 2 Interrupt Enable0x06WInterrupt enable for pins in Port 2
Port 3 Interrupt Enable0x07WInterrupt enable for pins in Port 3
GPIO Configuration0x08R/WGPIO Ports Configurations
USB Device Address A0x10R/WUSB Device Address A
EP A0 Counter Register0x11R/WUSB Address A, Endpoint 0 counter register
EP A0 Mode Register0x12R/WUSB Address A, Endpoint 0 configuration register
EP A1 Counter Register0x13R/WUSB Address A, Endpoint 1 counter register
EP A1 Mode Register0x14R/CUSB Address A, Endpoint 1 configuration register
EP A2 Counter Register0x15R/WUSB Address A, Endpoint 2 counter register
EP A2 Mode Register0x16R/CUSB Address A, Endpoint 2 configuration register
USB Status & Control0x1FR/WUSB upstream port traffic status and control register
Global Interrupt Enable0x20R/WGlobal interrupt enable register
Endpoint Interrupt Enable0x21R/WUSB endpoint interrupt enables
Timer (LSB)0x24RLower eight bits of free-running timer (1 MHz)
Timer (MSB)0x25RUpper four bits of free-running timer that are latched
WDR Clear0x26WWatch Dog Reset clear
DAC Data0x30R/WDAC I/O
DAC Interrupt Enable0x31WInterrupt enable for each DAC pin
DAC Interrupt Polarity0x32WInte rrupt polari ty for each DAC pin
DAC Isink0x38-0x3FWOne four bit sink current register for each DAC pin
Processor Status & Control0xFFR/WMicroprocessor status and control
Note:
2. DAC I/O Port not bonded out on CY7C63613C. See note on page 12 for firmware code needed for unused GPIO pins.
lator to the selected port. Indexed I/O Write (IOWX) adds the
contents of X to the address in the instruction to form the port
address and writes data from the accumulator to the specified
port. Note that specifying address 0 (e.g., IOWX 0h) means
the I/O port is selected solely by the contents of X.
when the lower eight bits are read.
[2]
Document #: 38-08027 Rev. *BPage 9 of 32
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Clock Distribution
clk1x
(to USB SIE)
clk2x
(to Microcontroller)
Clock
Doubler
30 pF
Figure 2. Clock Oscillator On-chip Circuit
30 pF
CY7C63413C
CY7C63513C
CY7C63613C
XTALOUT
XTALIN
Clocking
The XTALIN and XTAL
troller. The user can connect a low-cost ceramic resonator or
an external oscillator can be connected to these pins to
provide a reference frequency for the internal clock distribution
and clock doubler.
An external 6-MHz clock can be applied to the XTAL
the XTAL
XTAL
tively shorted to ground.
pin is left open. Please note that grounding the
OUT
pin is not permissible as the internal clock is effec-
OUT
are the clock pins to the microcon-
OUT
IN
pin if
Reset
The USB Controller supports three types of resets. All
registers are restored to their default states during a reset. The
USB Device Addresses are set to 0 and all interrupts are
disabled. In addition, the Program Stack Pointer (PSP) and
Data Stack Pointer (DSP) are set to 0x00. For USB applications, the firmware should set the DSP below 0xE8 to avoid a
memory conflict with RAM dedicated to USB FIFOs. The
assembly instructions to do this are shown below:
Mov A, E8h; Move 0xE8 hex into Accumulator
Swap A,dsp; Swap accumulator value into dsp register
The three reset types are:
1. Power-On Reset (POR)
2. Watch Dog Reset (WDR)
3. USB Bus Reset (non hardware reset)
The occurrence of a reset is recorded in the Processor Status
and Control Register located at I/O address 0xFF. Bits 4, 5,
and 6 are used to record the occurrence of POR, USB Reset,
and WDR respectively. The firmware can interrogate these bits
to determine the cause of a reset.
The microcontroller begins execution from ROM address
0x0000 after a POR or WDR reset. Although this looks like
interrupt vector 0, there is an important difference. Reset
8.192 ms
to 14.336 ms
processing does NOT push the program counter, carry flag,
and zero flag onto program stack. That means the reset
handler in firmware should initialize the hardware and begin
executing the “main” loop of code. Attempting to execute either
a RET or RETI in the reset handler will cause unpredictable
execution results.
Power-On Reset (POR)
Power-On Reset (POR) occurs every time the V
the device ramps from 0V to an internally defined trip voltage
(Vrst) of approximately 1/2 full supply voltage. In addition to the
normal reset initialization noted under “Reset,” bit 4 (PORS) of
the Processor Status and Control Register is set to “1” to
indicate to the firmware that a Power-On Reset occurred. The
POR event forces the GPIO ports into input mode (high
impedance), and the state of Port 3 bit 7 is used to control how
the part will respond after the POR releases.
If Port 3 bit 7 is HIGH (pulled to V
the idle state (DM HIGH and DP LOW) the part will go into a
semi-permanent power down/suspend mode, waiting for the
USB IO to go to one of Bus Reset, K (resume) or SE0. If Port
3 bit 7 is still HIGH when the part comes out of suspend, then
a 128-µs timer starts, delaying CPU operation until the ceramic
resonator has stabilized.
If Port 3 bit 7 was LOW (pulled to V
ms timer, delaying CPU operation until V
then continuing to run as reset.
Firmware should clear the POR Status (PORS) bit in register
0xFF before going into suspend as this status bit selects the
128-µs or 96-ms start-up timer value as follows: IF Port 3 bit 7
is HIGH then 128-µs is always used; ELSE if PORS is HIGH
then 96-ms is used; ELSE 128-µs is used.
Watch Dog Reset (WDR)
The Watch Dog Timer Reset (WDR) occurs when the Most
Significant Bit (MSB) of the 2-bit Watch Dog Timer Register
transitions from LOW to HIGH. In addition to the normal reset
) and the USB IO are at
CC
) the part will start a 96-
SS
CC
voltage to
CC
has stabilized,
2.048 ms
At least 8.192 ms
since last write to WDT
Document #: 38-08027 Rev. *BPage 10 of 32
WDR goes high
for 2.048 ms
Figure 3. Watch Dog Reset (WDR)
Execution begins at
Reset Vector 0X00
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