STMicroelectronics ST7LITE2 Technical data
ST7LITE2
8-BIT MCU WITH SINGLE VOLTAGE FLASH MEMORY,
DATA EEPROM, ADC, TIMERS, SPI
■ Memories
– 8 Kbytes single voltage Flash Program mem-
ory with read-out protection, In-Circuit Programming and In-Application programming
(ICP and IAP). 10K write/erase cycles guaranteed, data retention: 20 years at 55°C.
– 384 bytes RAM
■ Clock, Reset and Supply Management
DIP20
– Enhanced reset system
– Enhanced low voltage supervisor (LVD) for
main supply and an auxiliary voltage detector
(AVD) with interrupt capability for implementing safe power-down procedures
– Clock sources: Internal 1% RC oscillator,
crystal/ceramic resonator or external clock
– Internal 32-MHz input clock for Auto-reload
timer
– Optional x4 or x8 PLL for 4 or 8 MHz internal
clock
– Five Power Saving Modes: Halt, Active-Halt,
Wait and Slow, Auto Wake Up From Halt
■ I/O Ports
– Up to 15 multifunctional bidirectional I/O lines
–7 high sink outputs
■ 4 Timers
– Configurable Watchdog Timer
– Two 8-bit Lite Timers with prescaler,
1 realtime base and 1 input capture
– One 12-bit Auto-reload Timer with 4 PWM
outputs, input capture and output compare
■ 1 Communication Interface
– SPI synchronous serial interface
■ Interrupt Management
– 10 interrupt vectors plus TRAP and RESET
– 15 external interrupt lines (on 4 vectors)
■ A/D Converter
– 7 input channels
– Fixed gain Op-amp
– 13-bit resolution for 0 to 430 mV (@ 5V V
– 10-bit resolution for 430 mV to 5V (@ 5V V
■ Instruction Set
– 8-bit data manipulation
– 63 basic instructions with illegal opcode de-
tection
– 17 main addressing modes
– 8 x 8 unsigned multiply instructions
■ Development Tools
– Full hardware/software development package
– DM (Debug Module)
functions
Device Summary
Features ST7LITE20 ST7LITE25 ST7LITE29
Program memory - bytes 8K
RAM (stack) - bytes 384 (128)
Data EEPROM - bytes - - 256
Peripherals
Operating Supply 2.4V to 5.5V
CPU Frequency
Operating Temperature -40°C to +85°C
Packages SO20 300”, DIP20
Lite Timer with Watchdog,
Autoreload Timer, SPI,
10-bit ADC with Op-Amp
Up to 8Mhz
(w/ ext OSC up to 16MHz)
Lite Timer with Watchdog,
Autoreload Timer with 32-MHz input clock,
SPI, 10-bit ADC with Op-Amp
Up to 8Mhz (w/ ext OSC up to 16MHz
and int 1MHz RC 1% PLLx8/4MHz)
SO20
300”
DD
DD
)
)
Rev. 3.0
October 2004 1/131
1
Table of Contents
1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2 PIN DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
3 REGISTER & MEMORY MAP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
4 FLASH PROGRAM MEMORY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
4.1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
4.2 MAIN FEATURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
4.3 PROGRAMMING MODES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
4.4 ICC INTERFACE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
4.5 MEMORY PROTECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
4.6 RELATED DOCUMENTATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
4.7 REGISTER DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5 DATA EEPROM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
5.1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
5.2 MAIN FEATURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
5.3 MEMORY ACCESS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
5.4 POWER SAVING MODES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
5.5 ACCESS ERROR HANDLING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
5.6 DATA EEPROM READ-OUT PROTECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
5.7 REGISTER DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
6 CENTRAL PROCESSING UNIT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
6.1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
6.2 MAIN FEATURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
6.3 CPU REGISTERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
7 SUPPLY, RESET AND CLOCK MANAGEMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
7.1 INTERNAL RC OSCILLATOR ADJUSTMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
7.2 PHASE LOCKED LOOP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
7.3 REGISTER DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
7.4 MULTI-OSCILLATOR (MO) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
7.5 RESET SEQUENCE MANAGER (RSM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
7.6 SYSTEM INTEGRITY MANAGEMENT (SI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
8 INTERRUPTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
8.1 NON MASKABLE SOFTWARE INTERRUPT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
8.2 EXTERNAL INTERRUPTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
8.3 PERIPHERAL INTERRUPTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
9 POWER SAVING MODES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
9.1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
9.2 SLOW MODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
9.3 WAIT MODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
9.4 HALT MODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
9.5 ACTIVE-HALT MODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
9.6 AUTO WAKE UP FROM HALT MODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
10 I/O PORTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
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10.1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
10.2 FUNCTIONAL DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
10.3 I/O PORT IMPLEMENTATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
10.4 UNUSED I/O PINS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
10.5 LOW POWER MODES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
10.6 INTERRUPTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
10.7 DEVICE-SPECIFIC I/O PORT CONFIGURATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
11 ON-CHIP PERIPHERALS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
11.1 WATCHDOG TIMER (WDG) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
11.2 12-BIT AUTORELOAD TIMER 2 (AT2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
11.3 LITE TIMER 2 (LT2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
11.4 SERIAL PERIPHERAL INTERFACE (SPI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
11.5 10-BIT A/D CONVERTER (ADC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
12 INSTRUCTION SET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
12.1 ST7 ADDRESSING MODES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
12.2 INSTRUCTION GROUPS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
13 ELECTRICAL CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
13.1 PARAMETER CONDITIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
13.2 ABSOLUTE MAXIMUM RATINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
13.3 OPERATING CONDITIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
13.4 SUPPLY CURRENT CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
13.5 CLOCK AND TIMING CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
13.6 MEMORY CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
13.7 EMC CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
13.8 I/O PORT PIN CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
13.9 CONTROL PIN CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
13.10 COMMUNICATION INTERFACE CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . 112
13.11 10-BIT ADC CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114
14 PACKAGE CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118
14.1 PACKAGE MECHANICAL DATA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118
14.2 SOLDERING AND GLUEABILITY INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
15 DEVICE CONFIGURATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
15.1 OPTION BYTES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
15.2 DEVICE ORDERING INFORMATION AND TRANSFER OF CUSTOMER CODE . . . . 123
15.3 DEVELOPMENT TOOLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
15.4 ST7 APPLICATION NOTES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126
16 IMPORTANT NOTES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
16.1 EXECUTION OF BTJX INSTRUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
16.2 ADC CONVERSION SPURIOUS RESULTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
16.3 A/ D CONVERTER ACCURACY FOR FIRST CONVERSION . . . . . . . . . . . . . . . . . . . 129
16.4 NEGATIVE INJECTION IMPACT ON ADC ACCURACY . . . . . . . . . . . . . . . . . . . . . . . 129
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16.5 CLEARING ACTIVE INTERRUPTS OUTSIDE INTERRUPT ROUTINE . . . . . . . . . . . . 129
16.6 USING PB4 AS EXTERNAL INTERRUPT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
17 REVISION HISTORY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130
To obtain the most recent version of this datasheet,
please check at www.st.com>products>technical literature>datasheet
Please also pay special attention to the Section “IMPORTANT NOTES” on page 129.
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1 INTRODUCTION
ST7LITE2
The ST7LITE2 is a member of the ST7 microcontroller family. All ST7 devices are based on a common industry-standard 8-bit core, featuring an enhanced instruction set.
The ST7LITE2 features FLASH memory with
byte-by-byte In-Circuit Programming (ICP) and InApplication Programming (IAP) capability.
Under software control, the ST7LITE2 device can
be placed in WAIT, SLOW, or HALT mode, reducing power consumption when the application is in
idle or standby state.
The enhanced instruction set and addressing
modes of the ST7 offer both power and flexibility to
Figure 1. General Block Diagram
PLL
8MHz -> 32MHz
Int.
1% RC
CLKIN
OSC1
OSC2
V
DD
V
SS
RESET
Ext.
OSC
1MHz
to
16MHz
1MHz
PLL x 8
or PLL X4
/ 2
Internal
CLOCK
LVD
POWER
SUPPLY
CONTROL
software developers, enabling the design of highly
efficient and compact application code. In addition
to standard 8-bit data management, all ST7 microcontrollers feature true bit manipulation, 8x8 unsigned multiplication and indirect addressing
modes.
For easy reference, all parametric data are located
in section 13 on page 91.
The devices feature an on-chip Debug Module
(DM) to support in-circuit debugging (ICD). For a
description of the DM registers, refer to the ST7
ICC Protocol Reference Manual.
12-Bit
Auto-Reload
TIMER 2
8-Bit
LITE TIMER 2
PA7:0
(8 bits)
PB6:0
(7 bits)
ADDRESS AND DATA BUS
PORT A
PORT B
ADC
+ OpAmp
SPI
8-BIT CORE
ALU
PROGRAM
MEMORY
(8K Bytes)
RAM
(384 Bytes)
Debug Module
DATA EEPROM
(256 Bytes)
WATCHDOG
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ST7LITE2
2 PIN DESCRIPTION
Figure 2. 20-Pin SO Package Pinout
RESET
/AIN0/PB0
SS
SCK/AIN1/PB1
MISO/AIN2/PB2
MOSI/AIN3/PB3
CLKIN/AIN4/PB4
AIN5/PB5
AIN6/PB6
Figure 3. 20-Pin DIP Package Pinout
MISO/AIN2/PB2
MOSI/AIN3/PB3
CLKIN/AIN4/PB4
AIN5/PB5
AIN6/PB6
PA7(HS)
MCO/ICCCLK/BREAK/PA6
ATPWM3/ICCDATA/PA5(HS)
ATPWM2/PA4(HS)
ATPWM1/PA3(HS)
V
V
SS
DD
1
2
3
4
5
6
7
8
9
10
1
2
3
4
5
6
7
8
9
10
ei3
ei2
ei0
ei1
ei3
ei3
ei2
ei1
ei0
ei0
OSC1/CLKIN
20
OSC2
19
PA0 (HS)/LTIC
18
PA1 (HS)/ATIC
17
PA2 (HS)/ATPWM0
16
PA3 (HS)/ATPWM1
15
PA4 (HS)/ATPWM2
14
PA5 (HS)/ATPWM3/ICCDATA
13
PA6/MCO/ICCCLK/BREAK
12
PA7(HS)
11
(HS) 20mA high sink capability
eix associated external interrupt vector
SCK/AIN1/PB1
20
/AIN0/PB0
SS
19
RESET
18
V
17
DD
V
16
SS
OSC1/CLKIN
15
OSC2
14
PA0(HS)/LTIC
13
PA1(HS)/ATIC
12
PA2(HS)/ATPWM0
11
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1
(HS) 20mA high sink capability
eix associated external interrupt vector
ST7LITE2
PIN DESCRIPTION (Cont’d)
Legend / Abbreviations for Table 1:
Type: I = input, O = output, S = supply
In/Output level: C
Output level: HS = 20mA high sink (on N-buffer only)
Port and control configuration:
– Input: float = floating, wpu = weak pull-up, int = interrupt, ana = analog
– Output: OD = open drain, PP = push-pull
The RESET configuration of each pin is shown in bold which is valid as long as the device is in reset state.
Table 1. Device Pin Description
= CMOS 0.3VDD/0.7VDD with input trigger
T
Pin No.
Level Port / Control
Pin Name
Type
SO20
DIP20
116V
217V
3 18 RESET
SS
DD
I/O C
4 19 PB0/AIN0/SS
Input
S Ground
S Main power supply
T
I/O C
5 20 PB1/AIN1/SCK I/O C
6 1 PB2/AIN2/MISO I/O C
7 2 PB3/AIN3/MOSI I/O C
8 3 PB4/AIN4/CLKIN I/O C
9 4 PB5/AIN5 I/O C
10 5 PB6/AIN6 I/O C
11 6 PA7 I/O C
T
Input Output
Function
Alternate Function
(after reset)
Main
Output
float
int
wpu
ana
XX
PP
OD
Top priority non maskable interrupt (active
low)
ADC Analog Input 0 or SPI
Slave Select (active low)
X
T
XXXPort B0
Caution: No negative current
injection allowed on this pin.
For details, refer to section
13.2.2 on page 92
ei3
ADC Analog Input 1 or SPI Serial Clock
X XXXPort B1
T
Caution: No negative current
injection allowed on this pin.
For details, refer to section
13.2.2 on page 92
X XXXPort B2
T
X
T
ei2
X XXXPort B4
T
X XXXPort B5 ADC Analog Input 5
T
X XXXPort B6 ADC Analog Input 6
T
XXXPort B3
ADC Analog Input 2 or SPI
Master In/ Slave Out Data
ADC Analog Input 3 or SPI
Master Out / Slave In Data
ADC Analog Input 4 or External clock input
HS X ei1 X X Port A7
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1
ST7LITE2
Pin No.
Level Port / Control
Main
SO20
DIP20
Pin Name
Type
Input Output
Input
Output
float
wpu
int
ana
OD
Function
(after reset)
PP
Alternate Function
Main Clock Output or In Circuit
Communication Clock or External BREAK
Caution: During normal operation this pin must be pulledup, internally or externally (ex-
12 7
PA6 /MCO/
ICCCLK/BREAK
I/O C
X ei1 XXPort A6
T
ternal pull-up of 10k mandatory in noisy environment). This
is to avoid entering ICC mode
unexpectedly during a reset.
In the application, even if the
pin is configured as output,
any reset will put it back in input pull-up
13 8
PA5 /ATPWM3/
ICCDATA
I/O C
14 9 PA4/ATPWM2 I/O C
15 10 PA3/ATPWM1 I/O C
16 11 PA2/ATPWM0 I/O C
17 12 PA1/ATIC I/O C
18 13 PA0/LTIC I/O C
HS X
T
HS X XXPort A4 Auto-Reload Timer PWM2
T
HS X
T
HS X XXPort A2 Auto-Reload Timer PWM0
T
ei1
XXPort A5
XXPort A3 Auto-Reload Timer PWM1
ei0
HS X XXPort A1
T
HS X XXPort A0 Lite Timer Input Capture
T
Auto-Reload Timer PWM3 or
In Circuit Communication Data
Auto-Reload Timer Input Capture
19 14 OSC2 O Resonator oscillator inverter output
20 15 OSC1/CLKIN I
Resonator oscillator inverter input or External clock input
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1
3 REGISTER & MEMORY MAP
ST7LITE2
As shown in Figure 4, the MCU is capable of addressing 64K bytes of memories and I/O registers.
The available memory locations consist of 128
bytes of register locations, 384 bytes of RAM, 256
bytes of data EEPROM and 8 Kbytes of user program memory. The RAM space includes up to 128
bytes for the stack from 180h to 1FFh.
The highest address bytes contain the user reset
and interrupt vectors.
The Flash memory contains two sectors (see Fig-
ure 4) mapped in the upper part of the ST7 ad-
Figure 4. Memory Map
0080h
0000h
007Fh
0080h
01FFh
0200h
0FFFh
1000h
10FFh
1100h
HW Registers
(see Table 2)
RAM
(384 Bytes)
Reserved
Data EEPROM
(256 Bytes)
00FFh
0100h
017Fh
0180h
01FFh
dressing space so the reset and interrupt vectors
are located in Sector 0 (F000h-FFFFh).
The size of Flash Sector 0 and other device options are configurable by Option byte (refer to sec-
tion 15.1 on page 121).
IMPORTANT: Memory locations marked as “Reserved” must never be accessed. Accessing a reseved area can have unpredictable effects on the
device.l
Short Addressing
RAM (zero page)
16-bit Addressing
RAM
128 Bytes Stack
1000h
1001h
RCCR0
RCCR1
DFFFh
E000h
FFDFh
FFE0h
FFFFh
Reserved
Flash Memory
(8K)
Interrupt & Reset Vectors
(see Table 5)
E000h
FBFFh
FC00h
FFFFh
8K FLASH
PROGRAM MEMORY
7 Kbytes
SECTOR 1
1 Kbyte
SECTOR 0
FFDFh
see section 7.1 on page 23
FFDEh
RCCR0
RCCR1
see section 7.1 on page 23
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1
ST7LITE2
Table 2. Hardware Register Map
Address Block Register Label Register Name Reset Status Remarks
0000h
0001h
0002h
0003h
0004h
0005h
0006h
0007h
0008h
0009h
000Ah
000Bh
000Ch
000Dh
000Eh
000Fh
0010h
0011h
0012h
0013h
0014h
0015h
0016h
0017h
0018h
0019h
001Ah
001Bh
001Ch
001Dh
001Eh
001Fh
0020h
0021h
0022h
Port A
Port B
LITE
TIMER 2
AUTO-
RELOAD
TIMER 2
PADR
PADDR
PAOR
PBDR
PBDDR
PBOR
LTCSR2
LTARR
LTCNTR
LTCSR1
LTICR
ATCSR
CNTRH
CNTRL
ATRH
ATRL
PWMCR
PWM0CSR
PWM1CSR
PWM2CSR
PWM3CSR
DCR0H
DCR0L
DCR1H
DCR1L
DCR2H
DCR2L
DCR3H
DCR3L
ATICRH
ATICRL
TRANCR
BREAKCR
Port A Data Register
Port A Data Direction Register
Port A Option Register
Port B Data Register
Port B Data Direction Register
Port B Option Register
Reserved Area (2 bytes)
Lite Timer Control/Status Register 2
Lite Timer Auto-reload Register
Lite Timer Counter Register
Lite Timer Control/Status Register 1
Lite Timer Input Capture Register
Timer Control/Status Register
Counter Register High
Counter Register Low
Auto-Reload Register High
Auto-Reload Register Low
PWM Output Control Register
PWM 0 Control/Status Register
PWM 1 Control/Status Register
PWM 2 Control/Status Register
PWM 3 Control/Status Register
PWM 0 Duty Cycle Register High
PWM 0 Duty Cycle Register Low
PWM 1 Duty Cycle Register High
PWM 1 Duty Cycle Register Low
PWM 2 Duty Cycle Register High
PWM 2 Duty Cycle Register Low
PWM 3 Duty Cycle Register High
PWM 3 Duty Cycle Register Low
Input Capture Register High
Input Capture Register Low
Transfer Control Register
Break Control Register
1)
FFh
00h
40h
1)
FFh
00h
00h
0Fh
00h
00h
0X00 0000h
xxh
0X00 0000h
00h
00h
00h
00h
00h
00h
00h
00h
00h
00h
00h
00h
00h
00h
00h
00h
00h
00h
00h
01h
00h
R/W
R/W
R/W
R/W
R/W
2)
R/W
R/W
R/W
Read Only
R/W
Read Only
R/W
Read Only
Read Only
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Read Only
Read Only
R/W
R/W
0023h to
002Dh
002Eh WDG WDGCR Watchdog Control Register 7Fh R/W
0002Fh FLASH FCSR Flash Control/Status Register 00h R/W
00030h EEPROM EECSR Data EEPROM Control/Status Register 00h R/W
0031h
0032h
0033h
0034h
0035h
0036h
10/131
SPI
ADC
SPIDR
SPICR
SPICSR
ADCCSR
ADCDRH
ADCDRL
SPI Data I/O Register
SPI Control Register
SPI Control Status Register
A/D Control Status Register
A/D Data Register High
A/D Amplifier Control/Data Low Register
Reserved area (11 bytes)
xxh
0xh
00h
00h
xxh
0xh
1
R/W
R/W
R/W
R/W
Read Only
R/W
ST7LITE2
Address Block Register Label Register Name Reset Status Remarks
0037h ITC EICR External Interrupt Control Register 00h R/W
0038h MCC MCCSR Main Clock Control/Status Register 00h R/W
0039h
003Ah
003Bh Reserved area (1 byte)
003Ch ITC EISR External Interrupt Selection Register 0Ch R/W
003Dh to
0048h
0049h
004Ah
004Bh
004Ch
004Dh
004Eh
004Fh
0050h
0051h to
007Fh
Clock and
Reset
AWU
3)
DM
RCCR
SICSR
AWUPR
AWUCSR
DMCR
DMSR
DMBK1H
DMBK1L
DMBK2H
DMBK2L
RC oscillator Control Register
System Integrity Control/Status Register
Reserved area (12 bytes)
AWU Prescaler Register
AWU Control/Status Register
DM Control Register
DM Status Register
DM Breakpoint Register 1 High
DM Breakpoint Register 1 Low
DM Breakpoint Register 2 High
DM Breakpoint Register 2 Low
Reserved area (47 bytes)
FFh
0000 0XX0h
FFh
00h
00h
00h
00h
00h
00h
00h
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Legend: x=undefined, R/W=read/write
Notes:
1. The contents of the I/O port DR registers are readable only in output configuration. In input configuration, the values of the I/O pins are returned instead of the DR register contents.
2. The bits associated with unavailable pins must always keep their reset value.
3. For a description of the Debug Module registers, see ICC reference manual.
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1
ST7LITE2
4 FLASH PROGRAM MEMORY
4.1 Introduction
The ST7 single voltage extended Flash (XFlash) is
a non-volatile memory that can be electrically
erased and programmed either on a byte-by-byte
basis or up to 32 bytes in parallel.
The XFlash devices can be programmed off-board
(plugged in a programming tool) or on-board using
In-Circuit Programming or In-Application Programming.
The array matrix organisation allows each sector
to be erased and reprogrammed without affecting
other sectors.
4.2 Main Features
■ ICP (In-Circuit Programming)
■ IAP (In-Application Programming)
■ ICT (In-Circuit Testing) for downloading and
executing user application test patterns in RAM
■ Sector 0 size configurable by option byte
■ Read-out and write protection
4.3 PROGRAMMING MODES
The ST7 can be programmed in three different
ways:
– Insertion in a programming tool. In this mode,
FLASH sectors 0 and 1, option byte row and
data EEPROM (if present) can be programmed or erased.
– In-Circuit Programming. In this mode, FLASH
sectors 0 and 1, option byte row and data
EEPROM (if present) can be programmed or
erased without removing the device from the
application board.
– In-Application Programming. In this mode,
sector 1 and data EEPROM (if present) can
be programmed or erased without removing
the device from the application board and
while the application is running.
4.3.1 In-Circuit Programming (ICP)
ICP uses a protocol called ICC (In-Circuit Communication) which allows an ST7 plugged on a printed circuit board (PCB) to communicate with an external programming device connected via cable.
ICP is performed in three steps:
Switch the ST7 to ICC mode (In-Circuit Communications). This is done by driving a specific signal
sequence on the ICCCLK/DATA pins while the
RESET pin is pulled low. When the ST7 enters
ICC mode, it fetches a specific RESET vector
which points to the ST7 System Memory containing the ICC protocol routine. This routine enables
the ST7 to receive bytes from the ICC interface.
– Download ICP Driver code in RAM from the
ICCDATA pin
– Execute ICP Driver code in RAM to program
the FLASH memory
Depending on the ICP Driver code downloaded in
RAM, FLASH memory programming can be fully
customized (number of bytes to program, program
locations, or selection of the serial communication
interface for downloading).
4.3.2 In Application Programming (IAP)
This mode uses an IAP Driver program previously
programmed in Sector 0 by the user (in ICP
mode).
This mode is fully controlled by user software. This
allows it to be adapted to the user application, (user-defined strategy for entering programming
mode, choice of communications protocol used to
fetch the data to be stored etc).
IAP mode can be used to program any memory areas except Sector 0, which is write/erase protected to allow recovery in case errors occur during
the programming operation.
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1
FLASH PROGRAM MEMORY (Cont’d)
ST7LITE2
4.4 ICC interface
ICP needs a minimum of 4 and up to 6 pins to be
connected to the programming tool. These pins
are:
– RESET
–V
: device reset
: device power supply ground
SS
– ICCCLK: ICC output serial clock pin
– ICCDATA: ICC input serial data pin
– OSC1: main clock input for external source
(not required on devices without OSC1/OSC2
pins)
: application board power supply (option-
–V
DD
al, see Note 3)
Notes:
1. If the ICCCLK or ICCDATA pins are only used
as outputs in the application, no signal isolation is
necessary. As soon as the Programming Tool is
plugged to the board, even if an ICC session is not
in progress, the ICCCLK and ICCDATA pins are
not available for the application. If they are used as
inputs by the application, isolation such as a serial
resistor has to be implemented in case another device forces the signal. Refer to the Programming
Tool documentation for recommended resistor values.
2. During the ICP session, the programming tool
must control the RESET
pin. This can lead to conflicts between the programming tool and the application reset circuit if it drives more than 5mA at
high level (push pull output or pull-up resistor<1K).
A schottky diode can be used to isolate the application RESET circuit in this case. When using a
classical RC network with R>1K or a reset management IC with open drain output and pull-up resistor>1K, no additional components are needed.
In all cases the user must ensure that no external
reset is generated by the application during the
ICC session.
3. The use of Pin 7 of the ICC connector depends
on the Programming Tool architecture. This pin
must be connected when using most ST Programming Tools (it is used to monitor the application
power supply). Please refer to the Programming
Tool manual.
4. Pin 9 has to be connected to the OSC1 pin of
the ST7 when the clock is not available in the application or if the selected clock option is not programmed in the option byte. ST7 devices with multi-oscillator capability need to have OSC2 grounded in this case.
5. With the ICP option disabled with ST7 MDT10EPB that the external clock has to be provided on
PB4.
Caution: During normal operation the ICCCLK pin
must be pulled- up, internally or externally (external pull-up of 10k mandatory in noisy environment). This is to avoid entering ICC mode unexpectedly during a reset. In the application, even if
the pin is configured as output, any reset will put it
back in input pull-up.
Figure 5. Typical ICC Interface
(See Note 3)
APPLICATION
POWER SUPPLY
C
L2
VDD
OSC2
OPTIONAL
(See Note 4)
C
CLKIN
OSC1/PB4
(See Note 5)
PROGRAMMING TOOL
ICC CONNECTOR
ICC Cable
ICC CONNECTOR
HE10 CONNECTOR TYPE
975 3
L1
ST7
1
246810
RESET
ICCCLK
ICCDATA
APPLICATION BOARD
APPLICATION
RESET SOURCE
See Note 2
See Note 1 and Caution
APPLICATION
I/O
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1
ST7LITE2
FLASH PROGRAM MEMORY (Cont’d)
4.5 Memory Protection
There are two different types of memory protection: Read Out Protection and Write/Erase Protection which can be applied individually.
4.5.1 Read out Protection
Readout protection, when selected provides a protection against program memory content extraction and against write access to Flash memory.
Even if no protection can be considered as totally
unbreakable, the feature provides a very high level
of protection for a general purpose microcontroller.
Both program and data E
2
memory are protected.
In flash devices, this protection is removed by reprogramming the option. In this case, both program and data E
2
memory are automatically
erased and the device can be reprogrammed.
Read-out protection selection depends on the de-
vice type:
– In Flash devices it is enabled and removed
through the FMP_R bit in the option byte.
– In ROM devices it is enabled by mask option
specified in the Option List.
4.5.2 Flash Write/Erase Protection
Write/erase protection, when set, makes it impossible to both overwrite and erase program memory. It does not apply to E
2
data. Its purpose is to
provide advanced security to applications and prevent any change being made to the memory content.
Warning: Once set, Write/erase protection can
never be removed. A write-protected flash device
is no longer reprogrammable.
Write/erase protection is enabled through the
FMP_W bit in the option byte.
4.6 Related Documentation
For details on Flash programming and ICC protocol, refer to the ST7 Flash Programming Reference Manual and to the ST7 ICC Protocol Reference Manual
.
4.7 Register Description
FLASH CONTROL/STATUS REGISTER (FCSR)
Read/Write
Reset Value: 000 0000 (00h)
1st RASS Key: 0101 0110 (56h)
2nd RASS Key: 1010 1110 (AEh)
70
00000OPTLATPGM
Note: This register is reserved for programming
using ICP, IAP or other programming methods. It
controls the XFlash programming and erasing operations.
When an EPB or another programming tool is
used (in socket or ICP mode), the RASS keys are
sent automatically.
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1
5 DATA EEPROM
ST7LITE2
5.1 INTRODUCTION
The Electrically Erasable Programmable Read
Only Memory can be used as a non volatile backup for storing data. Using the EEPROM requires a
basic access protocol described in this chapter.
Figure 6. EEPROM Block Diagram
EECSR
ADDRESS
DECODER
0 E2LAT00 0 0 0 E2PGM
4
DECODER
ROW
5.2 MAIN FEATURES
■ Up to 32 Bytes programmed in the same cycle
■ EEPROM mono-voltage (charge pump)
■ Chained erase and programming cycles
■ Internal control of the global programming cycle
duration
■ WAIT mode management
■ Readout protection
HIGH VOLTAGE
PUMP
EEPROM
MEMORY MATRIX
(1 ROW = 32 x 8 BITS)
ADDRESS BUS
128128
4
4
DATA
MULTIPLEXER
DATA BUS
32 x 8 BITS
DATA LATCHES
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ST7LITE2
DATA EEPROM (Cont’d)
5.3 MEMORY ACCESS
The Data EEPROM memory read/write access
modes are controlled by the E2LAT bit of the EEPROM Control/Status register (EECSR). The flowchart in Figure 7 describes these different memory
access modes.
Read Operation (E2LAT=0)
The EEPROM can be read as a normal ROM location when the E2LAT bit of the EECSR register is
cleared. In a read cycle, the byte to be accessed is
put on the data bus in less than 1 CPU clock cycle.
This means that reading data from EEPROM
takes the same time as reading data from
EPROM, but this memory cannot be used to execute machine code.
Write Operation (E2LAT=1)
To access the write mode, the E2LAT bit has to be
set by software (the E2PGM bit remains cleared).
When a write access to the EEPROM area occurs,
Figure 7. Data EEPROM Programming Flowchart
READ MODE
E2LAT=0
E2PGM=0
the value is latched inside the 32 data latches according to its address.
When PGM bit is set by the software, all the previous bytes written in the data latches (up to 32) are
programmed in the EEPROM cells. The effective
high address (row) is determined by the last EEPROM write sequence. To avoid wrong programming, the user must take care that all the bytes
written between two programming sequences
have the same high address: only the five Least
Significant Bits of the address can change.
At the end of the programming cycle, the PGM and
LAT bits are cleared simultaneously.
Note: Care should be taken during the programming cycle. Writing to the same memory location
will over-program the memory (logical AND between the two write access data result) because
the data latches are only cleared at the end of the
programming cycle and by the falling edge of the
E2LAT bit.
It is not possible to read the latched data.
This note is ilustrated by the Figure 9.
WRITE MODE
E2LAT=1
E2PGM=0
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1
READ BYTES
IN EEPROM AREA
CLEARED BY HARDWARE
WRITE UP TO 32 BYTES
(with the same 11 MSB of the address)
IN EEPROM AREA
START PROGRAMMING CYCLE
E2PGM=1 (set by software)
E2LAT=1
01
E2LAT
DATA EEPROM (Cont’d)
2
Figure 8. Data E
DEFINITION
PROM Write Operation
⇓ Row / Byte ⇒ 0 1 2 3 ... 30 31 Physical Address
ROW
ST7LITE2
0
1
...
N
00h...1Fh
20h...3Fh
Nx20h...Nx20h+1Fh
E2LAT bit
E2PGM bit
Read operation impossible
Byte 1 Byte 2 Byte 32
PHASE 1
Writing data latches Waiting E2PGM and E2LAT to fall
Set by USER application
Programming cycle
PHASE 2
Read operation possible
Cleared by hardware
Note: If a programming cycle is interrupted (by software or a reset action), the integrity of the data in mem-
ory is not guaranteed.
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1
ST7LITE2
DATA EEPROM (Cont’d)
5.4 POWER SAVING MODES
Wait mode
The DATA EEPROM can enter WAIT mode on execution of the WFI instruction of the microcontroller or when the microcontroller enters Active-HALT
mode.The DATA EEPROM will immediately enter
this mode if there is no programming in progress,
otherwise the DATA EEPROM will finish the cycle
and then enter WAIT mode.
Active-Halt mode
Refer to Wait mode.
Halt mode
The DATA EEPROM immediately enters HALT
mode if the microcontroller executes the HALT instruction. Therefore the EEPROM will stop the
function in progress, and data may be corrupted.
5.5 ACCESS ERROR HANDLING
If a read access occurs while E2LAT=1, then the
data bus will not be driven.
If a write access occurs while E2LAT=0, then the
data on the bus will not be latched.
If a programming cycle is interrupted (by software/
RESET action), the memory data will not be guaranteed.
5.6 Data EEPROM Read-out Protection
The read-out protection is enabled through an option bit (see section 15.1 on page 121).
When this option is selected, the programs and
data stored in the EEPROM memory are protected
against read-out (including a re-write protection).
In Flash devices, when this protection is removed
by reprogramming the Option Byte, the entire Program memory and EEPROM is first automatically
erased.
Note: Both Program Memory and data EEPROM
are protected using the same option bit.
Figure 9. Data EEPROM Programming Cycle
READ OPERATION NOT POSSIBLE
INTERNAL
PROGRAMMING
VOLTAGE
ERASE CYCLE WRITE CYCLE
WRITE OF
DATA LATCHES
t
PROG
READ OPERATION POSSIBLE
LAT
PGM
18/131
1
DATA EEPROM (Cont’d)
5.7 REGISTER DESCRIPTION
EEPROM CONTROL/STATUS REGISTER (EECSR)
Read/Write
Reset Value: 0000 0000 (00h)
70
000000E2LATE2PGM
Bits 7:2 = Reserved, forced by hardware to 0.
Bit 1 = E2LAT Latch Access Transfer
This bit is set by software. It is cleared by hardware at the end of the programming cycle. It can
only be cleared by software if the E2PGM bit is
cleared.
0: Read mode
1: Write mode
ST7LITE2
Bit 0 = E2PGM Programming control and status
This bit is set by software to begin the programming
cycle. At the end of the programming cycle, this bit
is cleared by hardware.
0: Programming finished or not yet started
1: Programming cycle is in progress
Note: if the E2PGM bit is cleared during the programming cycle, the memory data is not guaranteed
Table 3. DATA EEPROM Register Map and Reset Values
Address
(Hex.)
0030h
Register
Label
EECSR
Reset Value
76543210
000000
E2LAT0E2PGM
0
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1
ST7LITE2
6 CENTRAL PROCESSING UNIT
6.1 INTRODUCTION
This CPU has a full 8-bit architecture and contains
six internal registers allowing efficient 8-bit data
manipulation.
6.2 MAIN FEATURES
■ 63 basic instructions
■ Fast 8-bit by 8-bit multiply
■ 17 main addressing modes
■ Two 8-bit index registers
■ 16-bit stack pointer
■ Low power modes
■ Maskable hardware interrupts
■ Non-maskable software interrupt
6.3 CPU REGISTERS
The 6 CPU registers shown in Figure 10 are not
present in the memory mapping and are accessed
by specific instructions.
Figure 10. CPU Registers
70
RESET VALUE = XXh
70
RESET VALUE = XXh
70
RESET VALUE = XXh
Accumulator (A)
The Accumulator is an 8-bit general purpose register used to hold operands and the results of the
arithmetic and logic calculations and to manipulate
data.
Index Registers (X and Y)
In indexed addressing modes, these 8-bit registers
are used to create either effective addresses or
temporary storage areas for data manipulation.
(The Cross-Assembler generates a precede instruction (PRE) to indicate that the following instruction refers to the Y register.)
The Y register is not affected by the interrupt automatic procedures (not pushed to and popped from
the stack).
Program Counter (PC)
The program counter is a 16-bit register containing
the address of the next instruction to be executed
by the CPU. It is made of two 8-bit registers PCL
(Program Counter Low which is the LSB) and PCH
(Program Counter High which is the MSB).
ACCUMULATOR
X INDEX REGISTER
Y INDEX REGISTER
15 8
RESET VALUE = RESET VECTOR @ FFFEh-FFFFh
15
RESET VALUE = STACK HIGHER ADDRESS
20/131
PCH
RESET VALUE =
7
70
1C11HI NZ
1X11X1XX
70
8
PCL
1
0
PROGRAM COUNTER
CONDITION CODE REGISTER
STACK POINTER
X = Undefined Value
CPU REGISTERS (Cont’d)
CONDITION CODE REGISTER (CC)
Read/Write
Reset Value: 111x1xxx
70
111HINZC
because the I bit is set by hardware at the start of
the routine and reset by the IRET instruction at the
end of the routine. If the I bit is cleared by software
in the interrupt routine, pending interrupts are
serviced regardless of the priority level of the current interrupt routine.
Bit 2 = N Negative.
The 8-bit Condition Code register contains the interrupt mask and four flags representative of the
result of the instruction just executed. This register
can also be handled by the PUSH and POP instructions.
These bits can be individually tested and/or controlled by specific instructions.
This bit is set and cleared by hardware. It is repre-
sentative of the result sign of the last arithmetic,
logical or data manipulation. It is a copy of the 7
bit of the result.
0: The result of the last operation is positive or null.
1: The result of the last operation is negative
(i.e. the most significant bit is a logic 1).
This bit is accessed by the JRMI and JRPL instrucBit 4 = H Half carry.
tions.
This bit is set by hardware when a carry occurs be-
tween bits 3 and 4 of the ALU during an ADD or
ADC instruction. It is reset by hardware during the
same instructions.
0: No half carry has occurred.
1: A half carry has occurred.
This bit is tested using the JRH or JRNH instruction. The H bit is useful in BCD arithmetic subroutines.
Bit 1 = Z Zero.
This bit is set and cleared by hardware. This bit in-
dicates that the result of the last arithmetic, logical
or data manipulation is zero.
0: The result of the last operation is different from
zero.
1: The result of the last operation is zero.
This bit is accessed by the JREQ and JRNE test
instructions.
Bit 3 = I Interrupt mask.
This bit is set by hardware when entering in interrupt or by software to disable all interrupts except
the TRAP software interrupt. This bit is cleared by
software.
0: Interrupts are enabled.
1: Interrupts are disabled.
This bit is controlled by the RIM, SIM and IRET instructions and is tested by the JRM and JRNM instructions.
Note: Interrupts requested while I is set are
latched and can be processed when I is cleared.
Bit 0 = C Carry/borrow.
This bit is set and cleared by hardware and soft-
ware. It indicates an overflow or an underflow has
occurred during the last arithmetic operation.
0: No overflow or underflow has occurred.
1: An overflow or underflow has occurred.
This bit is driven by the SCF and RCF instructions
and tested by the JRC and JRNC instructions. It is
also affected by the “bit test and branch”, shift and
rotate instructions.
By default an interrupt routine is not interruptable
ST7LITE2
th
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1
ST7LITE2
CPU REGISTERS (Cont’d)
STACK POINTER (SP)
Read/Write
Reset Value: 01FFh
15 8
00000001
70
1 SP6 SP5 SP4 SP3 SP2 SP1 SP0
The Stack Pointer is a 16-bit register which is always pointing to the next free location in the stack.
It is then decremented after data has been pushed
onto the stack and incremented before data is
popped from the stack (see Figure 11).
Since the stack is 128 bytes deep, the 9 most significant bits are forced by hardware. Following an
MCU Reset, or after a Reset Stack Pointer instruction (RSP), the Stack Pointer contains its reset value (the SP6 to SP0 bits are set) which is the stack
higher address.
The least significant byte of the Stack Pointer
(called S) can be directly accessed by a LD instruction.
Note: When the lower limit is exceeded, the Stack
Pointer wraps around to the stack upper limit, with-
out indicating the stack overflow. The previously
stored information is then overwritten and there-
fore lost. The stack also wraps in case of an under-
flow.
The stack is used to save the return address dur-
ing a subroutine call and the CPU context during
an interrupt. The user may also directly manipulate
the stack by means of the PUSH and POP instruc-
tions. In the case of an interrupt, the PCL is stored
at the first location pointed to by the SP. Then the
other registers are stored in the next locations as
shown in Figure 11.
– When an interrupt is received, the SP is decre-
mented and the context is pushed on the stack.
– On return from interrupt, the SP is incremented
and the context is popped from the stack.
A subroutine call occupies two locations and an in-
terrupt five locations in the stack area.
Figure 11. Stack Manipulation Example
@ 0180h
SP
@ 01FFh
CALL
Subroutine
SP
PCH
PCL
Stack Higher Address = 01FFh
Stack Lower Address =
Interrupt
Event
SP
CC
A
X
PCH
PCL
PCH
PCL
0180h
PUSH Y POP Y IRET
SP
Y
CC
A
X
PCH
PCL
PCH
PCL
CC
A
X
PCH
PCL
PCH
PCL
SP
PCH
PCL
RET
or RSP
SP
22/131
1
7 SUPPLY, RESET AND CLOCK MANAGEMENT
The device includes a range of utility features for
securing the application in critical situations (for
example in case of a power brown-out), and reducing the number of external components.
Main features
■ Clock Management
– 1 MHz internal RC oscillator (enabled by op-
tion byte, available on ST7LITE25 and
ST7LITE29 devices only)
– 1 to 16 MHz or 32kHz External crystal/ceramic
resonator (selected by option byte)
– External Clock Input (enabled by option byte)
– PLL for multiplying the frequency by 8 or 4
(enabled by option byte)
– For clock ART counter only: PLL32 for multi-
plying the 8 MHz frequency by 4 (enabled by
option byte). The 8 MHz input frequency is
mandatory and can be obtained in the follow-
ing ways:
–1 MHz RC + PLLx8
–16 MHz external clock (internally divided
by 2)
–2 MHz. external clock (internally divided by
2) + PLLx8
–Crystal oscillator with 16 MHz output fre-
quency (internally divided by 2)
■ Reset Sequence Manager (RSM)
■ System Integrity Management (SI)
– Main supply Low voltage detection (LVD) with
reset generation (enabled by option byte)
– Auxiliary Voltage detector (AVD) with interrupt
capability for monitoring the main supply (en-
abled by option byte)
7.1 INTERNAL RC OSCILLATOR ADJUSTMENT
The device contains an internal RC oscillator with
an accuracy of 1% for a given device, temperature
and voltage range (4.5V-5.5V). It must be calibrated to obtain the frequency required in the application. This is done by software writing a calibration
value in the RCCR (RC Control Register).
Whenever the microcontroller is reset, the RCCR
returns to its default value (FFh), i.e. each time the
device is reset, the calibration value must be loaded in the RCCR. Predefined calibration values are
stored in EEPROM for 3 and 5V V
ages at 25°C, as shown in the following table.
supply volt-
DD
RCCR Conditions
RCCR0
RCCR1
Note:
– See “ELECTRICAL CHARACTERISTICS” on
page 91. for more information on the frequency
and accuracy of the RC oscillator.
– To improve clock stability, it is recommended to
place a decoupling capacitor between the V
and V
SS
– These two bytes are systematically programmed
by ST, including on FASTROM devices. Consequently, customers intending to use FASTROM
service must not use these two bytes.
– RCCR0 and RCCR1 calibration values will be
erased if the read-out protection bit is reset after
it has been set. See “Read out Protection” on
page 14.
Caution: If the voltage or temperature conditions
change in the application, the frequency may need
to be recalibrated.
Refer to application note AN1324 for information
on how to calibrate the RC frequency using an external reference signal.
7.2 PHASE LOCKED LOOP
The PLL can be used to multiply a 1MHz frequency from the RC oscillator or the external clock by 4
or 8 to obtain f
bled and the multiplication factor of 4 or 8 is selected by 2 option bits.
– The x4 PLL is intended for operation with V
the 2.4V to 3.3V range
– The x8 PLL is intended for operation with V
the 3.3V to 5.5V range
Refer to Section 15.1 for the option byte description.
If the PLL is disabled and the RC oscillator is enabled, then f
If both the RC oscillator and the PLL are disabled,
is driven by the external clock.
f
OSC
V
DD
=25°C
T
A
=1MHz
f
RC
V
DD
=25°C
T
A
=700KHz
f
RC
pins.
OSC =
ST7LITE29
Address
=5V
=3V
OSC
1000h
and FFDEh
1001h
and FFDFh
of 4 or 8 MHz. The PLL is ena-
1MHz.
ST7LITE2
ST7LITE25
Address
FFDEh
FFDFh
DD
DD
DD
in
in
23/131
1
ST7LITE2
PHASE LOCKED LOOP (Cont’d)
Figure 12. PLL Output Frequency Timing
Diagram
LOCKED bit set
4/8 x
input
freq.
t
STAB
t
LOCK
t
STARTUP
Output freq.
t
When the PLL is started, after reset or wakeup
from Halt mode or AWUFH mode, it outputs the
clock after a delay of t
STARTUP
.
When the PLL output signal reaches the operating
frequency, the LOCKED bit in the SICSCR register
is set. Full PLL accuracy (ACC
a stabilization time of t
STAB
) is reached after
PLL
(see Figure 12 and
13.3.4 Internal RC Oscillator and PLL)
Refer to section 7.6.4 on page 33 for a description
of the LOCKED bit in the SICSR register.
7.3 REGISTER DESCRIPTION
MAIN CLOCK CONTROL/STATUS REGISTER
(MCCSR)
Read / Write
Reset Value: 0000 0000 (00h)
70
000000
MCO SMS
Bits 7:2 = Reserved, must be kept cleared.
Bit 1 = MCO Main Clock Out enable
This bit is read/write by software and cleared by
hardware after a reset. This bit allows to enable
the MCO output clock.
0: MCO clock disabled, I/O port free for general
purpose I/O.
1: MCO clock enabled.
Bit 0 = SMS Slow Mode select
This bit is read/write by software and cleared by
hardware after a reset. This bit selects the input
OSC
or f
clock f
0: Normal mode (f
1: Slow mode (f
/32.
OSC
CPU = fOSC
CPU = fOSC
/32)
24/131
RC CONTROL REGISTER (RCCR)
Read / Write
Reset Value: 1111 1111 (FFh)
70
CR
CR70 CR60 CR50 CR40 CR30 CR20 CR10
0
Bits 7:0 = CR[7:0] RC Oscillator Frequency Ad-
justment Bits
These bits must be written immediately after reset
to adjust the RC oscillator frequency and to obtain
an accuracy of 1%. The application can store the
correct value for each voltage range in EEPROM
and write it to this register at start-up.
00h = maximum available frequency
FFh = lowest available frequency
Note: To tune the oscillator, write a series of different values in the register until the correct frequency is reached. The fastest method is to use a dichotomy starting with 80h.
1
Figure 13. Clock Management Block Diagram
ST7LITE2
CLKIN
CLKIN
/OSC1
OSC2
OSC,PLLOFF,
OSCRANGE[2:0]
Option bits
CLKIN
CLKIN
OSC
1-16 MHZ
or 32kHz
f
OSC
/32 DIVIDER
CR4CR7 CR0CR1CR2CR3CR6 CR5
Tunable
Oscillator1% RC
f
CPU
PLL 1MHz -> 8MHz
PLL 1MHz -> 4MHz
/2
DIVIDER
OSC
/2
DIVIDER
8-BIT
LITE TIMER 2 COUNTER
f
/32
OSC
f
OSC
1
0
RCCR
8MHz -> 32MHz
CLKIN/2
PLL
12-BIT
AT TIMER 2
RC OSC
PLLx4x8
CLKIN/2
OSC/2
OSC,PLLOFF,
OSCRANGE[2:0]
Option bits
f
LTIMER
(1ms timebase @ 8 MHz f
f
CPU
TO CPU AND
PERIPHERALS
f
OSC
OSC
)
MCO
SMS
MCCSR
f
CPU
MCO
25/131
1
ST7LITE2
7.4 MULTI-OSCILLATOR (MO)
The main clock of the ST7 can be generated by
four different source types coming from the multioscillator block (1 to 16MHz or 32kHz):
■ an external source
■ 5 crystal or ceramic resonator oscillators
■ an internal high frequency RC oscillator
Each oscillator is optimized for a given frequency
range in terms of consumption and is selectable
through the option byte. The associated hardware
configurations are shown in Table 4. Refer to the
electrical characteristics section for more details.
External Clock Source
In this external clock mode, a clock signal (square,
sinus or triangle) with ~50% duty cycle has to drive
the OSC1 pin while the OSC2 pin is tied to ground.
Note: when the Multi-Oscillator is not used, PB4 is
selected by default as external clock.
Crystal/Ceramic Oscillators
This family of oscillators has the advantage of producing a very accurate rate on the main clock of
the ST7. The selection within a list of 4 oscillators
with different frequency ranges has to be done by
option byte in order to reduce consumption (refer
to section 15.1 on page 121 for more details on the
frequency ranges). In this mode of the multi-oscillator, the resonator and the load capacitors have
to be placed as close as possible to the oscillator
pins in order to minimize output distortion and
start-up stabilization time. The loading capacitance values must be adjusted according to the
selected oscillator.
These oscillators are not stopped during the
RESET phase to avoid losing time in the oscillator
start-up phase.
Internal RC Oscillator
In this mode, the tunable 1%RC oscillator is used
as main clock source. The two oscillator pins have
to be tied to ground.
Table 4. ST7 Clock Sources
Hardware Configuration
OSC1 OSC2
External ClockCrystal/Ceramic ResonatorsInternal RC Oscillator
EXTERNAL
SOURCE
OSC1 OSC2
C
L1
OSC1 OSC2
ST7
ST7
LOAD
CAPACITORS
ST7
C
L2
26/131
1
7.5 RESET SEQUENCE MANAGER (RSM)
ST7LITE2
7.5.1 Introduction
The reset sequence manager includes three RESET sources as shown in Figure 15:
■ External RESET source pulse
■ Internal LVD RESET (Low Voltage Detection)
■ Internal WATCHDOG RESET
These sources act on the RESET
pin and it is al-
ways kept low during the delay phase.
The RESET service routine vector is fixed at ad-
dresses FFFEh-FFFFh in the ST7 memory map.
The basic RESET sequence consists of 3 phases
as shown in Figure 14:
■ Active Phase depending on the RESET source
■ 256 or 4096 CPU clock cycle delay (see table
below)
■ RESET vector fetch
The 256 or 4096 CPU clock cycle delay allows the
oscillator to stabilise and ensures that recovery
has taken place from the Reset state. The shorter
or longer clock cycle delay is automatically selected depending on the clock source chosen by option byte:
Clock Source
Internal RC Oscillator 256
External clock (connected to CLKIN pin) 256
External Crystal/Ceramic Oscillator
(connected to OSC1/OSC2 pins)
CPU clock
cycle delay
4096
The RESET vector fetch phase duration is 2 clock
cycles.
If the PLL is enabled by option byte, it outputs the
clock after an additional delay of t
STARTUP
(see
Figure 12).
Figure 14. RESET Sequence Phases
RESET
Active Phase
INTERNAL RESET
256 or 4096 CLOCK CYCLES
7.5.2 Asynchronous External RESET
The RESET
output with integrated R
pin is both an input and an open-drain
weak pull-up resistor.
ON
FETCH
VECTOR
pin
This pull-up has no fixed value but varies in accordance with the input voltage. It
can be pulled
low by external circuitry to reset the device. See
Electrical Characteristic section for more details.
A RESET signal originating from an external
source must have a duration of at least t
h(RSTL)in
in
order to be recognized (see Figure 16). This detection is asynchronous and therefore the MCU
can enter reset state even in HALT mode.
Figure 15. Reset Block Diagram
V
DD
R
ON
RESET
Filter
PULSE
GENERATOR
INTERNAL
RESET
WATCHDOG RESET
LVD RESET
27/131
1
ST7LITE2
RESET SEQUENCE MANAGER (Cont’d)
The RESET
plays a major role in EMS performance. In a noisy
environment, it is recommended to follow the
guidelines mentioned in the electrical characteristics section.
7.5.3 External Power-On RESET
If the LVD is disabled by option byte, to start up the
microcontroller correctly, the user must ensure by
means of an external reset circuit that the reset
signal is held low until V
level specified for the selected f
A proper reset signal for a slow rising V
can generally be provided by an external RC network connected to the RESET
Figure 16. RESET Sequences
pin is an asynchronous signal which
is over the minimum
DD
frequency.
OSC
supply
DD
pin.
V
DD
7.5.4 Internal Low Voltage Detector (LVD)
RESET
Two different RESET sequences caused by the internal LVD circuitry can be distinguished:
■ Power-On RESET
■ Voltage Drop RESET
The device RESET
pulled low when V
V
DD<VIT-
(falling edge) as shown in Figure 16.
The LVD filters spikes on V
pin acts as an output that is
DD<VIT+
(rising edge) or
larger than t
DD
g(VDD)
to
avoid parasitic resets.
7.5.5 Internal Watchdog RESET
The RESET sequence generated by a internal
Watchdog counter overflow is shown in Figure 16.
Starting from the Watchdog counter underflow, the
device RESET
low during at least t
pin acts as an output that is pulled
w(RSTL)out
.
V
IT+(LVD)
V
IT-(LVD)
EXTERNAL
RESET
SOURCE
RESET PIN
WATCHDOG
RESET
RUN
LVD
RESET
ACTIVE PHASE
RUN
t
h(RSTL)in
EXTERNAL
RESET
ACTIVE
PHASE
WATCHDOG UNDERFLOW
RUN RUN
INTERNAL RESET (256 or 4096 T
VECTOR FETCH
WATCHDOG
RESET
ACTIVE
PHASE
t
w(RSTL)out
CPU
)
28/131
1
7.6 SYSTEM INTEGRITY MANAGEMENT (SI)
ST7LITE2
The System Integrity Management block contains
the Low voltage Detector (LVD) and Auxiliary Voltage Detector (AVD) functions. It is managed by
the SICSR register.
Note: A reset can also be triggered following the
detection of an illegal opcode or prebyte code. Refer to section 12.2.1 on page 88 for further details.
7.6.1 Low Voltage Detector (LVD)
The Low Voltage Detector function (LVD) generates a static reset when the V
below a V
IT-(LVD)
reference value. This means that
supply voltage is
DD
it secures the power-up as well as the power-down
keeping the ST7 in reset.
The V
IT-(LVD)
lower than the V
reference value for a voltage drop is
IT+(LVD)
reference value for poweron in order to avoid a parasitic reset when the
MCU starts running and sinks current on the supply (hysteresis).
The LVD Reset circuitry generates a reset when
is below:
V
DD
–V
–V
IT+(LVD)
IT-(LVD)
when VDD is rising
when VDD is falling
The LVD function is illustrated in Figure 17.
The voltage threshold can be configured by option
byte to be low, medium or high.
Provided the minimum V
the oscillator frequency) is above V
value (guaranteed for
DD
IT-(LVD)
, the
MCU can only be in two modes:
– under full software control
– in static safe reset
In these conditions, secure operation is always ensured for the application without the need for external reset hardware.
During a Low Voltage Detector Reset, the RESET
pin is held low, thus permitting the MCU to reset
other devices.
Notes:
The LVD allows the device to be used without any
external RESET circuitry.
The LVD is an optional function which can be se-
lected by option byte.
It is recommended to make sure that the V
DD
supply voltage rises monotonously when the device is
exiting from Reset, to ensure the application functions properly.
Figure 17. Low Voltage Detector vs Reset
V
DD
V
IT+
(LVD)
V
IT-
(LVD)
RESET
V
hys
29/131
1
ST7LITE2
Figure 18. Reset and Supply Management Block Diagram
RESET
V
SS
V
DD
RESET SEQUENCE
MANAGER
(RSM)
WATCHDOG
TIMER (WDG)
STATUS FLAG
SYSTEM INTEGRITY MANAGEMENT
SICSR
00 LVDRFLOCKEDWDGRF0
LOW VOLTAGE
AUXILIARY VOLTAGE
AVD Interrupt Request
AVDIEAVDF
DETECTOR
(LVD)
DETECTOR
(AVD)
30/131
1
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