STMICROELECTRONICS ST72F60E2M1

ST7260
LOW SPEED USB 8-BIT MCU FAMILY WITH UP TO 8K FLASH/ROM
AND SERIAL COMMUNICATION INTERFACE (SCI)
■
■
■
■
Memories
– 4 or 8 Kbytes Program Memory: High Density
Flash (HDFlash), FastROM or ROM with Readout and Write Protection
– In-Application Programming (IAP) and In-Circuit programming (ICP)
– 384 bytes RAM memory (128-byte stack)
Clock, Reset and Supply Management
– Run, Wait, Slow and Halt CPU modes
– 12 or 24 MHz Oscillator
– RAM Retention mode
– Optional Low Voltage Detector (LVD)
USB (Universal Serial Bus) Interface
– DMA for low speed applications compliant
with USB 1.5 Mbs (version 2.0) and HID specifications (version 1.0)
– Integrated 3.3 V voltage regulator and transceivers
– Supports USB DFU class specification
– Suspend and Resume operations
– 3 Endpoints with programmable In/Out configuration
Up to 19 I/O Ports
– Up to 8 high sink I/Os (10 mA at 1.3 V)
– 2 very high sink true open drain I/Os (25 mA
at 1.5 V)
– Up to 8 lines individually programmable as interrupt inputs
SO24
■
■
■
■
QFN40
(6x6)
2 Timers
– Programmable Watchdog
– 16-bit Timer with 2 Input Captures, 2 Output
Compares, PWM output and clock input
1 Communication Interface
– Asynchronous Serial Communications Interface
Instruction Set
– 63 basic instructions
– 17 main addressing modes
– 8 x 8 unsigned multiply instruction
– True bit manipulation
Development Tools
– Versatile Development Tools (under Windows) including assembler, linker, C-compiler, archiver, source level debugger, software
library, hardware emulator, programming
boards and gang programmers, HID and DFU
software layers
Table 1. Device Summary
Features
Program Memory -bytes
(Flash or ROM)
ST7260K2
ST7260K1
ST7260E2
ST7260E1
8K
4K
8K
4K
RAM (stack) - bytes
384 (128)
Standard Peripherals
Watchdog timer, 16-bit timer, USB
Other Peripherals
SCI
Operating Supply
CPU frequency
4.0 V to 5.5 V
8 MHz (with 24 MHz oscillator) or 4 MHz (with 12 MHz oscillator)
Operating temperature
Packages
0 °C to +70 °C
QFN40 (6x6)
QFN40 (6x6)
SO24
Rev. 2.0
November 2006
1/117
1
Table of Contents
1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2 PIN DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3 REGISTER & MEMORY MAP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
4 FLASH PROGRAM MEMORY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
4.1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
4.2 MAIN FEATURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
4.3 STRUCTURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
4.4 ICC INTERFACE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
4.5 ICP (IN-CIRCUIT PROGRAMMING) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
4.6 IAP (IN-APPLICATION PROGRAMMING) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
4.7 RELATED DOCUMENTATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
4.8 REGISTER DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
5 CENTRAL PROCESSING UNIT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
5.1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
5.2 MAIN FEATURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
5.3 CPU REGISTERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
6 RESET AND CLOCK MANAGEMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
6.1 RESET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
6.2 CLOCK SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
7 INTERRUPTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
7.1 INTERRUPT REGISTER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
8 POWER SAVING MODES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
8.1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
8.2 HALT MODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
8.3 SLOW MODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
8.4 WAIT MODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
9 I/O PORTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
9.1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
9.2 FUNCTIONAL DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
10 MISCELLANEOUS REGISTER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
11 ON-CHIP PERIPHERALS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
11.1 WATCHDOG TIMER (WDG) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
11.2 16-BIT TIMER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
11.3 SERIAL COMMUNICATIONS INTERFACE (SCI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
11.4 USB INTERFACE (USB) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
12 INSTRUCTION SET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
12.1 ST7 ADDRESSING MODES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
12.2 INSTRUCTION GROUPS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
13 ELECTRICAL CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
13.1 PARAMETER CONDITIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
13.2 ABSOLUTE MAXIMUM RATINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117
. . . . 87
13.3 OPERATING CONDITIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
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Table of Contents
13.4 SUPPLY CURRENT CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
13.5 CLOCK AND TIMING CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
13.6 MEMORY CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
13.7 EMC CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
13.8 I/O PORT PIN CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
13.9 CONTROL PIN CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
13.10COMMUNICATION INTERFACE CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . 101
14 PACKAGE CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
14.1 PACKAGE MECHANICAL DATA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
14.2 THERMAL CHARACTERISTICS
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
14.3 SOLDERING AND GLUEABILITY INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106
15 DEVICE CONFIGURATION AND ORDERING INFORMATION . . . . . . . . . . . . . . . . . . . . . . . 107
15.1 OPTION BYTE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
15.2 DEVICE ORDERING INFORMATION AND TRANSFER OF CUSTOMER CODE . . . . . 108
15.3 DEVELOPMENT TOOLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
15.4 ST7 APPLICATION NOTES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
16 KNOWN LIMITATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114
16.1 PA2 LIMITATION WITH OCMP1 ENABLED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114
16.2 UNEXPECTED RESET FETCH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114
16.3 SCI WRONG BREAK DURATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114
16.4 USB BEHAVIOR WITH LVD DISABLED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114
17 REVISION HISTORY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
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ST7260
1 INTRODUCTION
The ST7260 Microcontrollers form a sub-family of
the ST7 MCUs dedicated to USB applications. The
devices are based on an industry-standard 8-bit
core and feature an enhanced instruction set.
They operate at a 24 MHz or 12 MHz oscillator frequency. Under software control, the ST7260
MCUs may be placed in either Wait or Halt modes,
thus reducing power consumption. The enhanced
instruction set and addressing modes afford real
programming potential. In addition to standard 8bit data management, the ST7260 MCUs feature
true bit manipulation, 8x8 unsigned multiplication
and indirect addressing modes. The devices include an ST7 Core, up to 8Kbytes of program
memory, up to 384 bytes of RAM, 19 I/O lines and
the following on-chip peripherals:
– USB low speed interface with 3 endpoints with
programmable in/out configuration using the
DMA architecture with embedded 3.3V voltage
regulator and transceivers (no external components are needed).
– Industry standard asynchronous SCI serial interface
– Watchdog
– 16-bit Timer featuring an External clock input, 2
Input Captures, 2 Output Compares with Pulse
Generator capabilities
– Low voltage reset (LVD) ensuring proper poweron or power-off of the device
The ST72F60 devices are Flash versions. They
support programming in IAP mode (In-application
programming) via the on-chip USB interface.
Figure 1. General Block Diagram
INTERNAL
CLOCK
OSC/3
OSCIN
OSCOUT
OSCILLATOR
OSC/4 or OSC/2
for USB1)
VDD
VSS
PORT A
PA[7:0]
(8 bits)
POWER
SUPPLY
16-BIT TIMER
WATCHDOG
CONTROL
8-BIT CORE
ALU
LVD
USB DMA
ADDRESS AND DATA BUS
RESET
PORT B
PORT C
SCI
VPP/TEST
VDDA
PROGRAM
MEMORY
(8K Bytes)
(UART)
USB SIE
VSSA
1) 12
4/117
PB[7:0]
(8 bits)
RAM
(384 Bytes)
or 24 MHz OSCIN frequency required to generate 6 MHz USB clock.
PC[2:0]
(3 bits)
USBDP
USBDM
USBVCC
ST7260
2 PIN DESCRIPTION
PA1(25mA)/ICCDATA
NC
NC
NC
NC
NC
NC
NC
NC
PA2(25mA)/ICCCLK
Figure 2. 40-Lead QFN Package Pinout
40
39
38
37
36
35
34
33
32
31
28
PA5/ICAP2/IT2
USBDM
4
27
PA6/OCMP1/IT3
USBVCC
5
26
PA7/OCMP2/IT4
VDDA
6
25
PB0(10mA)
VDD
7
24
PB1(10mA)
OSCOUT
8
23
PB2(10mA)
OSCIN
9
22
PB3(10mA)
10
21
PB4(10mA)/IT5
VSS
Note: NC=Do not connect
11
12
13
14
15
16
17
18
19
20
IT6/PB5(10mA)
3
VPP/TEST
USBDP
IT7/PB6(10mA)
PA4/ICAP1/IT1
IT8/PB7(10mA)
29
NC
2
NC
VSSA
RESET
PA3/EXTCLK
RDI/PC0
30
TDO/PC1
1
USBOE/PC2
PA0/MCO
5/117
ST7260
Figure 3. 24-Pin SO Package Pinout
6/117
VDD
OSCOUT
OSCIN
1
24
2
23
3
22
USBVcc
USBDM
USBDP
VSS
4
21
TDO/PC1
RDI/PC0
RESET/
IT7/PB6(10mA)
5
20
VSSA
PA0/MCO
6
19
PA1(25mA)/ICCDATA
7
18
8
17
PA2(25mA)/ICCCLK
PA3/EXTCLK
VPP/TEST
PB3(10mA)
9
16
PA4/ICAP1/IT1
10
15
PB2(10mA)
11
14
USBOE/PB1(10mA)
12
13
PA5/ICAP2/IT2
PA7/OCMP2/IT4
PB0(10mA)
ST7260
PIN DESCRIPTION (Cont’d)
RESET (see Note 1): Bidirectional. This active low
Note 1: Adding two 100 nF decoupling capacitors
signal forces the initialization of the MCU. This
on the Reset pin (respectively connected to VDD
and VSS) will significantly improve product electroevent is the top priority non maskable interrupt.
magnetic susceptibility performance.
This pin is switched low when the Watchdog is triggered or the VDD is low. It can be used to reset exNote 2: To enhance the reliability of operation, it is
ternal peripherals.
recommended that VDDA and VDD be connected together on the application board. This also applies
OSCIN/OSCOUT: Input/Output Oscillator pin.
to VSSA and VSS.
These pins connect a parallel-resonant crystal, or
an external source, to the on-chip oscillator.
Note 3: The USBOE alternate function is mapped
on Port C2 in QFN40 devices. In SO24 devices it
VDD/VSS (see Note 2): Main Power Supply and
Ground voltages.
is mapped on Port B1.
VDDA/VSSA (see Note 2): Power Supply and
Note 4: The timer OCMP1 alternate function is
mapped on Port A6 in QFN40 pin devices. In
Ground voltages for analog peripherals.
SO24 devices it is not available.
Alternate Functions: Several pins of the I/O ports
assume software programmable alternate functions as shown in the pin description.
Legend / Abbreviations for Table 2, Table 3:
Type:
I = input, O = output, S = supply
In/Output level: CT = CMOS 0.3 VDD / 0.7 VDD with input trigger
Output level:
10 mA = 10 mA high sink (Fn N-buffer only)
25 mA = 25 mA very high sink (on N-buffer only)
Port and control configuration:
– Input:
float = floating, wpu = weak pull-up, int = interrupt
– Output:
OD = open drain, PP = push-pull, T = True open drain
The RESET configuration of each pin is shown in
bold. This configuration is kept as long as the device is under reset state.
7/117
ST7260
Table 2. Device Pin Description (QFN40)
Port / Control
PP
OD
Output
int
wpu
Input
float
QFN40
Output
Pin Name
Input
Level
Type
Pin n°
Main
Function
(after reset)
Alternate Function
7
VDD
S
Power supply voltage (4V - 5.5V)
8
OSCOUT
O
Oscillator output
9
OSCIN
I
Oscillator input
10
VSS
S
Digital ground
11
PC2/USBOE
I/O
CT
X
X
Port C2
USB Output Enable
12
PC1/TDO
I/O
CT
X
X
Port C1
SCI Transmit Data Output
13
PC0/RDI
I/O CT
X
X
Port C0
SCI Receive Data Input
14
RESET
I/O
X
15
NC
--
Not connected
16
NC
--
Not connected
17
PB7/IT8
I/O CT 10mA X
X
X
Port B7
18
PB6/IT7
I/O CT 10mA X
X
X
Port B6
19
VPP/TEST
20
PB5/IT6
I/O CT 10mA X
X
X
Port B5
21
PB4/IT5
I/O CT 10mA X
X
X
Port B4
22
PB3
I/O CT 10mA X
X
Port B3
23
PB2
I/O CT 10mA X
X
Port B2
24
PB1
I/O CT 10mA X
X
Port B1
25
PB0
I/O CT 10mA X
X
Port B0
26
PA7/OCMP2/IT4
I/O
CT
X
X
X
Port A7
Timer Output Compare 2
27
PA6/OCMP1/IT3
I/O
CT
X
X
X
Port A6
Timer Output Compare 1
28
PA5/ICAP2/IT2
I/O
CT
X
X
X
Port A5
Timer Input Capture 2
29
PA4/ICAP1/IT1
I/O
CT
X
X
X
Port A4
Timer Input Capture 1
30
PA3/EXTCLK
I/O
CT
X
X
Port A3
Timer External Clock
31
PA2/ICCCLK
I/O CT 25mA X
Port A2
ICC Clock
32
NC
--
Do not connect
33
NC
--
Do not connect
34
NC
--
Do not connect
35
NC
--
Do not connect
36
NC
--
Do not connect
37
NC
--
Do not connect
38
NC
--
Do not connect
8/117
X
Reset
S
Programming supply
T
ST7260
Port / Control
PP
OD
Output
int
wpu
Input
float
Input
QFN40
Type
Pin Name
Output
Level
Pin n°
--
Main
Function
(after reset)
Alternate Function
39
NC
Do not connect
40
PA1/ICCDATA
I/O CT 25mA X
1
PA0/MCO
I/O
2
VSSA
3
USBDP
I/O
USB bidirectional data (data +)
4
USBDM
I/O
USB bidirectional data (data -)
5
USBVCC
O
USB power supply
6
VDDA
S
Analog supply voltage
T
CT
X
X
S
Port A1
ICC Data
Port A0
Main Clock Output
Analog ground
Table 3. Device Pin Description (SO24)
Port / Control
PP
OD
Output
int
wpu
Input
float
SO24
Output
Pin Name
Input
Level
Type
Pin n°
Main
Function
(after reset)
Alternate Function
1
VDD
S
Power supply voltage (4V - 5.5V)
2
OSCOUT
O
Oscillator output
3
OSCIN
I
Oscillator input
4
VSS
S
Digital ground
5
PC1/TDO
I/O
6
PC0/RDI
7
CT
X
X
Port C1
SCI Transmit Data Output
I/O CT
X
X
Port C0
SCI Receive Data Input
RESET
I/O
X
8
PB6/IT7
I/O CT 10mA X
9
VPP/TEST
10
PB3
I/O CT 10mA X
X
Port B3
11
PB2
I/O CT 10mA X
X
Port B2
12
PB1/USBOE
I/O CT 10mA X
X
Port B1
13
PB0
I/O CT 10mA X
X
Port B0
14
PA7/OCMP2/IT4
I/O
CT
X
X
X
Port A7
Timer Output Compare 2
15
PA5/ICAP2/IT2
I/O
CT
X
X
X
Port A5
Timer Input Capture 2
16
PA4/ICAP1/IT1
I/O
CT
X
X
X
Port A4
Timer Input Capture 1
17
PA3/EXTCLK
I/O
CT
X
X
Port A3
Timer External Clock
18
PA2/ICCCLK
I/O CT 25mA X
T
Port A2
ICC Clock
19
PA1/ICCDATA
I/O CT 25mA X
T
Port A1
ICC Data
X
X
Reset
X
S
Port B6
Programming supply
USB Output Enable
9/117
ST7260
X
PP
OD
Output
int
float
Input
X
Main
Function
(after reset)
Port A0
Alternate Function
PA0/MCO
21
VSSA
22
USBDP
I/O
USB bidirectional data (data +)
23
USBDM
I/O
USB bidirectional data (data -)
24
USBVCC
O
USB power supply
S
CT
Port / Control
20
10/117
I/O
Output
SO24
Input
Pin Name
Type
Level
wpu
Pin n°
Main Clock Output
Analog ground
ST7260
3 REGISTER & MEMORY MAP
As shown in Figure 4, the MCU is capable of addressing 8 Kbytes of memories and I/O registers.
The available memory locations consist of up to
384 bytes of RAM including 64 bytes of register locations, and up to 8K bytes of user program memory in which the upper 32 bytes are reserved for interrupt vectors. The RAM space includes up to 128
bytes for the stack from 0100h to 017Fh.
The highest address bytes contain the user reset
and interrupt vectors.
IMPORTANT: Memory locations noted “Reserved” must never be accessed. Accessing a reserved area can have unpredictable effects on the
device.
Figure 4. Memory Map
0040h
0000h
003Fh
0040h
HW Registers
(See Table 5)
00FFh
0100h
RAM
(384 Bytes)
Short Addressing
RAM (192 bytes)
Stack
(128 Bytes)
017Fh
0180h
01BFh
01C0h
16-bit Addressing
RAM
Reserved
01BFh
7FFFh
8000h
Program Memory
(4 / 8 KBytes)
FFDFh
FFE0h
FFFFh
Interrupt & Reset Vectors
(See Table 4)
E000h
8 KBytes
F000h
FFDFh
4 KBytes
Table 4. Interrupt Vector Map
Vector Address
Description
Masked by
Remarks
Exit from Halt Mode
FFE0h-FFEDh
Reserved Area
FFEEh-FFEFh
USB Interrupt Vector
I- bit
Internal Interrupt
No
FFF0h-FFF1h
SCI Interrupt Vector
I- bit
Internal Interrupt
No
FFF2h-FFF3h
FFF4h-FFF5h
Reserved Area
TIMER Interrupt Vector
I- bit
Internal Interrupt
No
FFF6h-FFF7h
IT1 to IT8 Interrupt Vector
I- bit
External Interrupt
Yes
FFF8h-FFF9h
USB End Suspend Mode Interrupt Vector
I- bit
External Interrupts
Yes
FFFAh-FFFBh
Flash Start Programming Interrupt Vector
I- bit
Internal Interrupt
Yes
FFFCh-FFFDh
TRAP (software) Interrupt Vector
None
CPU Interrupt
No
FFFEh-FFFFh
RESET Vector
None
Yes
11/117
ST7260
Table 5. Hardware Register Memory Map
Address
0000h
0001h
0002h
0003h
0004h
0005h
Block
Port A
Port B
Port C
Register Label
Register name
Reset Status
Remarks
PADR
Port A Data Register
00h
R/W
PADDR
Port A Data Direction Register
00h
R/W
PBDR
Port B Data Register
00h
R/W
PBDDR
Port B Data Direction Register
00h
R/W
PCDR
Port C Data Register
1111 x000b
R/W
PCDDR
Port C Data Direction Register
1111 x000b
R/W
0006h
to
0007h
Reserved (2 bytes)
0008h
ITC
ITIFRE
Interrupt Register
00h
R/W
0009h
MISC
MISCR
Miscellaneous Register
00h
R/W
7Fh
R/W
000Ah
to
000Bh
000Ch
Reserved (2 bytes)
WDG
WDGCR
000Dh
to
Watchdog Control Register
Reserved (4 bytes)
0010h
0011h
TCR2
Timer Control Register 2
00h
R/W
0012h
TCR1
Timer Control Register 1
00h
R/W
0013h
TCSR
Timer Control/Status Register
00h
R/W
0014h
TIC1HR
Timer Input Capture High Register 1
xxh
Read only
0015h
TIC1LR
Timer Input Capture Low Register 1
xxh
Read only
0016h
TOC1HR
Timer Output Compare High Register 1
80h
R/W
0017h
TOC1LR
Timer Output Compare Low Register 1
00h
R/W
TCHR
Timer Counter High Register
FFh
Read only
0019h
TCLR
Timer Counter Low Register
FCh
R/W
001Ah
TACHR
Timer Alternate Counter High Register
FFh
Read only
001Bh
TACLR
Timer Alternate Counter Low Register
FCh
R/W
001Ch
TIC2HR
Timer Input Capture High Register 2
xxh
Read only
001Dh
TIC2LR
Timer Input Capture Low Register 2
xxh
Read only
001Eh
TOC2HR
Timer Output Compare High Register 2
80h
R/W
001Fh
TOC2LR
Timer Output Compare Low Register 2
00h
R/W
0020h
SCISR
SCI Status Register
C0h
Read only
0021h
SCIDR
SCI Data Register
xxh
R/W
SCIBRR
SCI Baud Rate Register
00h
R/W
0023h
SCICR1
SCI Control Register 1
x000 0000b
R/W
0024h
SCICR2
SCI Control Register 2
00h
R/W
0018h
0022h
12/117
TIM
SCI
ST7260
Address
Block
Register Label
Register name
Reset Status
Remarks
0025h
USBPIDR
USB PID Register
x0h
Read only
0026h
USBDMAR
USB DMA address Register
xxh
R/W
0027h
USBIDR
USB Interrupt/DMA Register
x0h
R/W
0028h
USBISTR
USB Interrupt Status Register
00h
R/W
0029h
USBIMR
USB Interrupt Mask Register
00h
R/W
002Ah
USBCTLR
USB Control Register
06h
R/W
USBDADDR
USB Device Address Register
00h
R/W
002Ch
USBEP0RA
USB Endpoint 0 Register A
0000 xxxxb
R/W
002Dh
USBEP0RB
USB Endpoint 0 Register B
80h
R/W
002Eh
USBEP1RA
USB Endpoint 1 Register A
0000 xxxxb
R/W
002Fh
USBEP1RB
USB Endpoint 1 Register B
0000 xxxxb
R/W
0030h
USBEP2RA
USB Endpoint 2 Register A
0000 xxxxb
R/W
0031h
USBEP2RB
USB Endpoint 2 Register B
0000 xxxxb
R/W
00h
R/W
002Bh
USB
0032h
Reserved (5 Bytes)
0036h
0037h
0038h
to
003Fh
Flash
FCSR
Flash Control /Status Register
Reserved (8 bytes)
13/117
ST7260
4 FLASH PROGRAM MEMORY
4.1 INTRODUCTION
Depending on the overall Flash memory size in the
microcontroller device, there are up to three user
sectors (see Table 6). Each of these sectors can
be erased independently to avoid unnecessary
erasing of the whole Flash memory when only a
partial erasing is required.
The first two sectors have a fixed size of 4 Kbytes
(see Figure 5). They are mapped in the upper part
of the ST7 addressing space so the reset and interrupt vectors are located in Sector 0 (F000hFFFFh).
The ST7 dual voltage High Density Flash
(HDFlash) is a non-volatile memory that can be
electrically erased as a single block or by individual sectors and programmed on a Byte-by-Byte basis using an external VPP supply.
The HDFlash devices can be programmed and
erased off-board (plugged in a programming tool)
or on-board using ICP (In-Circuit Programming) or
IAP (In-Application Programming).
The array matrix organisation allows each sector
to be erased and reprogrammed without affecting
other sectors.
Table 6. Sectors available in Flash devices
Flash Size (bytes)
Available Sectors
4K
Sector 0
4.2 MAIN FEATURES
■
■
■
■
3 Flash programming modes:
– Insertion in a programming tool. In this mode,
all sectors including option bytes can be programmed or erased.
– ICP (In-Circuit Programming). In this mode, all
sectors including option bytes can be programmed or erased without removing the device from the application board.
– IAP (In-Application Programming) In this
mode, all sectors except Sector 0, can be programmed or erased without removing the device from the application board and while the
application is running.
ICT (In-Circuit Testing) for downloading and
executing user application test patterns in RAM
Read-out protection
Register Access Security System (RASS) to
prevent accidental programming or erasing
8K
Sectors 0,1
> 8K
Sectors 0,1, 2
4.3.1 Read-out Protection
Read-out 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.
In Flash devices, this protection is removed by reprogramming the option. In this case, the entire
program memory is first automatically erased and
the device can be reprogrammed.
Read-out protection selection depends on the device 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.
4.3 STRUCTURE
The Flash memory is organised in sectors and can
be used for both code and data storage.
Figure 5. Memory Map and Sector Address
4K
8K
10K
16K
24K
32K
48K
60K
1000h
FLASH
MEMORY SIZE
3FFFh
7FFFh
9FFFh
SECTOR 2
BFFFh
D7FFh
DFFFh
EFFFh
FFFFh
14/117
2 Kbytes
8 Kbytes
16 Kbytes 24 Kbytes 40 Kbytes 52 Kbytes
4 Kbytes
4 Kbytes
SECTOR 1
SECTOR 0
ST7260
FLASH PROGRAM MEMORY (Cont’d)
–
–
–
–
ICCCLK: ICC output serial clock pin
ICCDATA: ICC input/output serial data pin
ICCSEL/VPP: programming voltage
OSC1(or OSCIN): main clock input for external source (optional)
– VDD: application board power supply (see Figure 6, Note 3)
4.4 ICC INTERFACE
ICC (In-Circuit Communication) needs a minimum
of four and up to six pins to be connected to the
programming tool (see Figure 6). These pins are:
– RESET: device reset
– VSS: device power supply ground
Figure 6. Typical ICC Interface
PROGRAMMING TOOL
ICC CONNECTOR
ICC Cable
APPLICATION BOARD
(See Note 3)
ICC CONNECTOR
HE10 CONNECTOR TYPE
OPTIONAL
(See Note 4)
9
7
5
3
1
10
8
6
4
2
APPLICATION
RESET SOURCE
See Note 2
10kΩ
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 implemented in case another device forces the signal. Refer to the Programming
Tool documentation for recommended resistor values.
2. During the ICC 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 man-
ICCDATA
ICCCLK
ST7
RESET
See Note 1
ICCSEL/VPP
OSC1
CL1
OSC2
VDD
CL2
VSS
APPLICATION
POWER SUPPLY
APPLICATION
I/O
agement 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 or OSCIN 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.
15/117
ST7260
FLASH PROGRAM MEMORY (Cont’d)
4.5 ICP (IN-CIRCUIT PROGRAMMING)
4.7 RELATED DOCUMENTATION
To perform ICP the microcontroller must be
switched to ICC (In-Circuit Communication) mode
by an external controller or programming tool.
Depending on the ICP code downloaded in RAM,
Flash memory programming can be fully customized (number of bytes to program, program locations, or selection serial communication interface
for downloading).
When using an STMicroelectronics or third-party
programming tool that supports ICP and the specific microcontroller device, the user needs only to
implement the ICP hardware interface on the application board (see Figure 6). For more details on
the pin locations, refer to the device pinout description.
For details on Flash programming and ICC protocol, refer to the ST7 Flash Programming Reference Manual and to the ST7 ICC Protocol Reference Manual.
4.6 IAP (IN-APPLICATION PROGRAMMING)
This register is reserved for use by Programming
Tool software. It controls the Flash programming
and erasing operations.
This mode uses a BootLoader program previously
stored in Sector 0 by the user (in ICP mode or by
plugging the device in a programming tool).
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.). For example, it is
possible to download code from the SPI, SCI or
other type of serial interface and program it in the
Flash. IAP mode can be used to program any of
the Flash sectors except Sector 0, which is write/
erase protected to allow recovery in case errors
occur during the programming operation.
16/117
4.8 REGISTER DESCRIPTION
FLASH CONTROL/STATUS REGISTER (FCSR)
Read/Write
Reset Value: 0000 0000 (00h)
7
0
0
0
0
0
0
0
0
0
ST7260
5 CENTRAL PROCESSING UNIT
5.1 INTRODUCTION
This CPU has a full 8-bit architecture and contains
six internal registers allowing efficient 8-bit data
manipulation.
5.2 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
5.3 CPU REGISTERS
The six CPU registers shown in Figure 7 are not
present in the memory mapping and are accessed
by specific instructions.
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).
Figure 7. CPU Registers
7
0
ACCUMULATOR
RESET VALUE = XXh
7
0
X INDEX REGISTER
RESET VALUE = XXh
7
0
Y INDEX REGISTER
RESET VALUE = XXh
15
PCH
8 7
PCL
0
PROGRAM COUNTER
RESET VALUE = RESET VECTOR @ FFFEh-FFFFh
7
1 1 1 H I
0
N Z C
CONDITION CODE REGISTER
RESET VALUE = 1 1 1 X 1 X X X
15
8 7
0
STACK POINTER
RESET VALUE = STACK HIGHER ADDRESS
X = Undefined Value
17/117
ST7260
CPU REGISTERS (Cont’d)
CONDITION CODE REGISTER (CC)
Read/Write
Reset Value: 111x1xxx
7
1
0
1
1
H
I
N
Z
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.
C
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.
Bit 4 = H Half carry
This bit is set by hardware when a carry occurs between 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 2 = N Negative
This bit is set and cleared by hardware. It is representative of the result sign of the last arithmetic,
logical or data manipulation. It is a copy of the 7th
bit of the result.
0: The result of the last operation is positive or null.
1: The result of the last operation is negative
(that is, the most significant bit is a logic 1).
This bit is accessed by the JRMI and JRPL instructions.
Bit 1 = Z Zero
This bit is set and cleared by hardware. This bit indicates 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.
By default an interrupt routine is not interruptible
18/117
Bit 0 = C Carry/borrow
This bit is set and cleared by hardware and software. 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.
ST7260
CPU REGISTERS (Cont’d)
STACK POINTER (SP)
Read/Write
Reset Value: 017Fh
15
0
8
0
0
0
0
0
0
7
0
1
0
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 8).
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, without indicating the stack overflow. The previously
stored information is then overwritten and therefore lost. The stack also wraps in case of an underflow.
The stack is used to save the return address during 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 instructions. 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 8.
– When an interrupt is received, the SP is decremented 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 interrupt five locations in the stack area.
Figure 8. Stack Manipulation Example
CALL
Subroutine
PUSH Y
Interrupt
Event
POP Y
RET
or RSP
IRET
@ 0100h
SP
SP
CC
A
X
X
X
PCH
PCH
PCH
PCL
PCL
PCL
PCH
PCH
PCH
PCH
PCH
PCL
PCL
PCL
PCL
PCL
SP
@ 017Fh
SP
Y
CC
A
CC
A
SP
SP
Stack Higher Address = 017Fh
Stack Lower Address = 0100h
19/117
ST7260
6 RESET AND CLOCK MANAGEMENT
6.1 RESET
The Reset procedure is used to provide an orderly
software start-up or to exit low power modes.
Three reset modes are provided: a low voltage
(LVD) reset, a watchdog reset and an external reset at the RESET pin.
A reset causes the reset vector to be fetched from
addresses FFFEh and FFFFh in order to be loaded
into the PC and with program execution starting
from this point.
An internal circuitry provides a 4096 CPU clock cycle delay from the time that the oscillator becomes
active.
6.1.3 External Reset
The external reset is an active low input signal applied to the RESET pin of the MCU.
As shown in Figure 12, the RESET signal must
stay low for a minimum of one and a half CPU
clock cycles.
An internal Schmitt trigger at the RESET pin is provided to improve noise immunity.
Figure 9. Low Voltage Detector functional Diagram
RESET
VDD
6.1.1 Low Voltage Detector (LVD)
Low voltage reset circuitry generates a reset when
VDD is:
■ below VIT+ when VDD is rising,
■ below VIT- when VDD is falling.
LOW VOLTAGE
DETECTOR
INTERNAL
RESET
FROM
WATCHDOG
RESET
Figure 10. Low Voltage Reset Signal Output
During low voltage reset, the RESET pin is held low,
thus permitting the MCU to reset other devices.
It is recommended to make sure that the VDD supply voltage rises monotonously when the device is
exiting from Reset, to ensure the application functions properly.
6.1.2 Watchdog Reset
When a watchdog reset occurs, the RESET pin is
pulled low permitting the MCU to reset other devices in the same way as the low voltage reset (Figure 9).
VIT+
VDD
RESET
Note: Hysteresis (VIT+-VIT-) = Vhys
Figure 11. Temporization timing diagram after an internal Reset
VDD
VIT+
Temporization (4096 CPU clock cycles)
Addresses
20/117
$FFFE
VIT-
ST7260
RESET (Cont’d)
Figure 12. Reset Timing Diagram
tDDR
VDD
OSCIN
tOXOV
fCPU
PC
RESET
WATCHDOG RESET
FFFE
FFFF
4096 CPU
CLOCK
CYCLES
DELAY
Note: Refer to Electrical Characteristics for values of tDDR, tOXOV, VIT+, VIT- and Vhys
21/117
ST7260
6.2 CLOCK SYSTEM
6.2.1 General Description
The MCU accepts either a Crystal or Ceramic resonator, or an external clock signal to drive the internal oscillator. The internal clock (fCPU) is derived from the external oscillator frequency (fOSC),
which is divided by 3 (and by 2 or 4 for USB, depending on the external clock used). The internal
clock is further divided by 2 by setting the SMS bit
in the Miscellaneous Register.
Using the OSC24/12 bit in the option byte, a 12
MHz or a 24 MHz external clock can be used to
provide an internal frequency of either 2, 4 or 8
MHz while maintaining a 6 MHz for the USB (refer
to Figure 15).
The internal clock signal (fCPU) is also routed to
the on-chip peripherals. The CPU clock signal
consists of a square wave with a duty cycle of
50%.
The internal oscillator is designed to operate with
an AT-cut parallel resonant quartz or ceramic resonator in the frequency range specified for fosc.
The circuit shown in Figure 14 is recommended
when using a crystal, and Table 7, "Recommended Values for 24 MHz Crystal Resonator" lists the
recommended capacitance. The crystal and associated components should be mounted as close as
possible to the input pins in order to minimize output distortion and start-up stabilisation time.
source should be used instead of tOXOV (see Section 6.5 CONTROL TIMING).
Figure 13. External Clock Source Connections
OSCOUT
OSCIN
NC
EXTERNAL
CLOCK
Figure 14. Crystal/Ceramic Resonator
OSCOUT
OSCIN
RP
COSCIN
COSCOUT
Table 7. Recommended Values for 24 MHz
Crystal Resonator
RSMAX
20 Ω
25 Ω
70 Ω
COSCIN
56pF
47pF
22pF
COSCOUT
56pF
47pF
22pF
RP
1-10 MΩ
1-10 MΩ
1-10 MΩ
Note: RSMAX is the equivalent serial resistor of the
crystal (see crystal specification).
6.2.2 External Clock
An external clock may be applied to the OSCIN input with the OSCOUT pin not connected, as
shown on Figure 13. The tOXOV specifications do
not apply when using an external clock input. The
equivalent specification of the external clock
Figure 15. Clock Block Diagram
0
%2
%3
1
SMS
1
24 or
12 MHz
Crystal
%2
%2
%2
0
OSC24/12
22/117
8, 4 or 2 MHz
CPU and
peripherals)
6 MHz (USB)
ST7260
7 INTERRUPTS
The ST7 core may be interrupted by one of two different methods: maskable hardware interrupts as
listed in Table 8, "Interrupt Mapping" and a nonmaskable software interrupt (TRAP). The Interrupt
processing flowchart is shown in Figure 16.
The maskable interrupts must be enabled clearing
the I bit in order to be serviced. However, disabled
interrupts may be latched and processed when
they are enabled (see external interrupts subsection).
When an interrupt has to be serviced:
– Normal processing is suspended at the end of
the current instruction execution.
– The PC, X, A and CC registers are saved onto
the stack.
– The I bit of the CC register is set to prevent additional interrupts.
– The PC is then loaded with the interrupt vector of
the interrupt to service and the first instruction of
the interrupt service routine is fetched (refer to
Table 8, "Interrupt Mapping" for vector addresses).
The interrupt service routine should finish with the
IRET instruction which causes the contents of the
saved registers to be recovered from the stack.
Note: As a consequence of the IRET instruction,
the I bit will be cleared and the main program will
resume.
Priority Management
By default, a servicing interrupt cannot be interrupted because the I bit is set by hardware entering in interrupt routine.
In the case several interrupts are simultaneously
pending, a hardware priority defines which one will
be serviced first (see Table 8, "Interrupt Mapping").
Non-maskable Software Interrupts
This interrupt is entered when the TRAP instruction is executed regardless of the state of the I bit.
It will be serviced according to the flowchart on
Figure 16.
Interrupts and Low Power Mode
All interrupts allow the processor to leave the Wait
low power mode. Only external and specific mentioned interrupts allow the processor to leave the
Halt low power mode (refer to the “Exit from HALT“
column in Table 8, "Interrupt Mapping").
External Interrupts
The pins ITi/PAk and ITj/PBk (i=1,2; j= 5,6; k=4,5)
can generate an interrupt when a rising edge occurs on this pin. Conversely, the ITl/PAn and ITm/
PBn pins (l=3,4; m= 7,8; n=6,7) can generate an
interrupt when a falling edge occurs on this pin.
Interrupt generation will occur if it is enabled with
the ITiE bit (i=1 to 8) in the ITRFRE register and if
the I bit of the CCR is reset.
Peripheral Interrupts
Different peripheral interrupt flags in the status
register are able to cause an interrupt when they
are active if both:
– The I bit of the CC register is cleared.
– The corresponding enable bit is set in the control
register.
If any of these two conditions is false, the interrupt
is latched and thus remains pending.
Clearing an interrupt request is done by one of the
two following operations:
– Writing “0” to the corresponding bit in the status
register.
– Accessing the status register while the flag is set
followed by a read or write of an associated register.
Notes:
1. The clearing sequence resets the internal latch.
A pending interrupt (i.e. waiting to be enabled) will
therefore be lost if the clear sequence is executed.
2. All interrupts allow the processor to leave the
Wait low power mode.
3. Exit from Halt mode may only be triggered by an
External Interrupt on one of the ITi ports (PA4-PA7
and PB4-PB7), an end suspend mode Interrupt
coming from USB peripheral, or a reset.
23/117
ST7260
INTERRUPTS (Cont’d)
Figure 16. Interrupt Processing Flowchart
FROM RESET
BIT I SET
N
N
Y
Y
FETCH NEXT INSTRUCTION
N
INTERRUPT
IRET
STACK PC, X, A, CC
SET I BIT
LOAD PC FROM INTERRUPT VECTOR
Y
EXECUTE INSTRUCTION
RESTORE PC, X, A, CC FROM STACK
THIS CLEARS I BIT BY DEFAULT
Table 8. Interrupt Mapping
N°
Source
Block
RESET
Description
Reset
TRAP
Software Interrupt
FLASH
Flash Start Programming Interrupt
USB
1
ITi
2
TIMER
3
End Suspend Mode
Register
Label
Priority
Order
N/A
Highest
Priority
ISTR
External Interrupts
ITRFRE
Timer Peripheral Interrupts
TIMSR
Address
yes
FFFEh-FFFFh
no
FFFCh-FFFDh
yes
FFFAh-FFFBh
yes
FFF8h-FFF9h
FFF6h-FFF7h
FFF4h-FFF5h
Reserved
FFF2h-FFF3h
4
SCI
SCI Peripheral Interrupts
SCISR
5
USB
USB Peripheral Interrupts
ISTR
24/117
Vector
Exit
from
HALT
Lowest
Priority
no
FFF0h-FFF1h
FFEEh-FFEFh
ST7260
INTERRUPTS (Cont’d)
7.1 Interrupt Register
INTERRUPTS REGISTER (ITRFRE)
Address: 0008h — Read/Write
Reset Value: 0000 0000 (00h)
7
IT8E
0
IT7E
IT6E
IT5E
IT4E
IT3E
IT2E
IT1E
Bit 7:0 = ITiE (i=1 to 8). Interrupt Enable Control
Bits.
If an ITiE bit is set, the corresponding interrupt is
generated when
– a rising edge occurs on the pin PA4/IT1 or PA5/
IT2 or PB4/IT5 or PB5/IT6
or
– a falling edge occurs on the pin PA6/IT3 or PA7/
IT4 or PB6/IT7 or PB7/IT8
No interrupt is generated elsewhere.
25/117
ST7260
8 POWER SAVING MODES
8.1 Introduction
To give a large measure of flexibility to the application in terms of power consumption, two main power saving modes are implemented in the ST7.
After a RESET, the normal operating mode is selected by default (RUN mode). This mode drives
the device (CPU and embedded peripherals) by
means of a master clock which is based on the
main oscillator frequency divided by 3 (fCPU).
From Run mode, the different power saving
modes may be selected by setting the relevant
register bits or by calling the specific ST7 software
instruction whose action depends on the oscillator
status.
Figure 17. HALT Mode Flow Chart
HALT INSTRUCTION
OSCILLATOR
PERIPH. CLOCK
CPU CLOCK
OFF
OFF
OFF
CLEARED
I-BIT
8.2 HALT Mode
The MCU consumes the least amount of power in
HALT mode. The HALT mode is entered by executing the HALT instruction. The internal oscillator
is then turned off, causing all internal processing to
be stopped, including the operation of the on-chip
peripherals.
When entering HALT mode, the I bit in the Condition Code Register is cleared. Thus, all external interrupts (ITi or USB end suspend mode) are allowed and if an interrupt occurs, the CPU clock becomes active.
The MCU can exit HALT mode on reception of either an external interrupt on ITi, an end suspend
mode interrupt coming from USB peripheral, or a
reset. The oscillator is then turned on and a stabilization time is provided before releasing CPU operation. The stabilization time is 4096 CPU clock
cycles.
After the start up delay, the CPU continues operation by servicing the interrupt which wakes it up or
by fetching the reset vector if a reset wakes it up.
N
RESET
N
EXTERNAL
INTERRUPT*
Y
Y
OSCILLATOR
PERIPH. CLOCK
CPU CLOCK
I-BIT
ON
ON
ON
SET
4096 CPU CLOCK
CYCLES DELAY
FETCH RESET VECTOR
OR SERVICE INTERRUPT
Note: Before servicing an interrupt, the CC register is
pushed on the stack. The I-Bit is set during the interrupt routine and cleared when the CC register is
popped.
26/117
ST7260
POWER SAVING MODES (Cont’d)
8.3 SLOW Mode
In Slow mode, the oscillator frequency can be divided by 2 as selected by the SMS bit in the Miscellaneous Register. The CPU and peripherals are
clocked at this lower frequency. Slow mode is
used to reduce power consumption, and enables
the user to adapt the clock frequency to the available supply voltage.
Figure 18. WAIT Mode Flow Chart
WFI INSTRUCTION
OSCILLATOR
PERIPH. CLOCK
CPU CLOCK
8.4 WAIT Mode
WAIT mode places the MCU in a low power consumption mode by stopping the CPU.
This power saving mode is selected by calling the
“WFI” ST7 software instruction.
All peripherals remain active. During WAIT mode,
the I bit of the CC register is forced to 0 to enable
all interrupts. All other registers and memory remain unchanged. The MCU remains in WAIT
mode until an interrupt or Reset occurs, whereupon the Program Counter branches to the starting
address of the interrupt or Reset service routine.
The MCU will remain in WAIT mode until a Reset
or an Interrupt occurs, causing it to wake up.
Refer to Figure 18.
Related Documentation
AN 980: ST7 Keypad Decoding Techniques, Implementing Wake-Up on Keystroke
AN1014: How to Minimize the ST7 Power Consumption
AN1605: Using an active RC to wakeup the
ST7LITE0 from power saving mode
I-BIT
ON
ON
OFF
CLEARED
N
RESET
N
Y
INTERRUPT
Y
OSCILLATOR
PERIPH. CLOCK
CPU CLOCK
I-BIT
ON
ON
ON
SET
IF RESET
4096 CPU CLOCK
CYCLES DELAY
FETCH RESET VECTOR
OR SERVICE INTERRUPT
Note: Before servicing an interrupt, the CC register is
pushed on the stack. The I-Bit is set during the interrupt routine and cleared when the CC register is
popped.
27/117
ST7260
9 I/O PORTS
9.1 Introduction
The I/O ports offer different functional modes:
– Transfer of data through digital inputs and outputs and for specific pins
– Alternate signal input/output for the on-chip peripherals
– External interrupt generation
An I/O port consists of up to 8 pins. Each pin can
be programmed independently as a digital input
(with or without interrupt generation) or a digital
output.
9.2 Functional description
Each port is associated to 2 main registers:
– Data Register (DR)
– Data Direction Register (DDR)
Each I/O pin may be programmed using the corresponding register bits in DDR register: bit X corresponding to pin X of the port. The same correspondence is used for the DR register.
Table 9. I/O Pin Functions
DDR
MODE
0
Input
1
Output
Input Modes
The input configuration is selected by clearing the
corresponding DDR register bit.
In this case, reading the DR register returns the
digital value applied to the external I/O pin.
Note 1: All the inputs are triggered by a Schmitt
trigger.
Note 2: When switching from input mode to output
mode, the DR register should be written first to
output the correct value as soon as the port is configured as an output.
Interrupt function
When an I/O is configured as an Input with Interrupt, an event on this I/O can generate an external
Interrupt request to the CPU. The interrupt sensitivity is given independently according to the de-
28/117
scription mentioned in the ITRFRE interrupt register.
Each pin can independently generate an Interrupt
request.
Each external interrupt vector is linked to a dedicated group of I/O port pins (see Interrupts section). If more than one input pin is selected simultaneously as an interrupt source, this is logically
ORed. For this reason if one of the interrupt pins is
tied low, the other ones are masked.
Output Mode
The pin is configured in output mode by setting the
corresponding DDR register bit (see Table 7).
In this mode, writing “0” or “1” to the DR register
applies this digital value to the I/O pin through the
latch. Therefore, the previously saved value is restored when the DR register is read.
Note: The interrupt function is disabled in this
mode.
Digital Alternate Function
When an on-chip peripheral is configured to use a
pin, the alternate function is automatically selected. This alternate function takes priority over
standard I/O programming. When the signal is
coming from an on-chip peripheral, the I/O pin is
automatically configured in output mode (push-pull
or open drain according to the peripheral).
When the signal is going to an on-chip peripheral,
the I/O pin has to be configured in input mode. In
this case, the pin’s state is also digitally readable
by addressing the DR register.
Notes:
1. Input pull-up configuration can cause an unexpected value at the input of the alternate peripheral input.
2. When the on-chip peripheral uses a pin as input
and output, this pin must be configured as an input
(DDR = 0).
Warning: The alternate function must not be activated as long as the pin is configured as an input
with interrupt in order to avoid generating spurious
interrupts.
ST7260
I/O PORTS (Cont’d)
9.2.1 Port A
Table 10. Port A0, A3, A4, A5, A6, A7 Description
I/O
PORT A
Alternate Function
Input1
Output
Signal
Condition
PA0
with pull-up
push-pull
MCO (Main Clock Output)
PA3
with pull-up
push-pull
Timer EXTCLK
PA4
with pull-up
PA5
with pull-up
PA62
with pull-up
PA7
Reset State
2
Not available on SO24
CC1 =1
CC0 = 1 (Timer CR2)
Timer ICAP1
push-pull
IT1 Schmitt triggered input
IT1E = 1 (ITIFRE)
Timer ICAP2
push-pull
push-pull
with pull-up
1
MCO = 1 (MISCR)
push-pull
IT2 Schmitt triggered input
IT2E = 1 (ITIFRE)
Timer OCMP1
OC1E = 1
IT3 Schmitt triggered input
IT3E = 1 (ITIFRE)
Timer OCMP2
OC2E = 1
IT4 Schmitt triggered input
IT4E = 1 (ITIFRE)
Figure 19. PA0, PA3, PA4, PA5, PA6, PA7 Configuration
ALTERNATE ENABLE
ALTERNATE 1
OUTPUT
VDD
0
P-BUFFER
VDD
DR
PULL-UP
DATA BUS
LATCH
ALTERNATE ENABLE
DDR
LATCH
PAD
DDR SEL
N-BUFFER
DR SEL
ALTERNATE INPUT
1
0
DIODES
ALTERNATE ENABLE
VSS
CMOS SCHMITT TRIGGER
29/117
ST7260
I/O PORTS (Cont’d)
Table 11. PA1, PA2 Description
PORT A
I/O
Alternate Function
Input1
Output
PA1
without pull-up
Very High Current open drain
PA2
without pull-up
Very High Current open drain
1
Signal
Condition
Reset State
Figure 20. PA1, PA2 Configuration
ALTERNATE ENABLE
ALTERNATE 1
OUTPUT
0
DR
LATCH
DDR
LATCH
DATA BUS
PAD
DDR SEL
N-BUFFER
DR SEL
1
ALTERNATE ENABLE
VSS
0
CMOS SCHMITT TRIGGER
30/117
ST7260
I/O PORTS (Cont’d)
9.2.2 Port B
Table 12. Port B Description
PORT B
I/O
Input1
Alternate Function
Output
PB0
without pull-up
push-pull
PB1
without pull-up
push-pull
PB2
without pull-up
push-pull
PB3
without pull-up
push-pull
PB4
without pull-up
push-pull
PB5
without pull-up
PB6
without pull-up
PB7
1Reset
2
without pull-up
Signal
Condition
USBOE (USB output enable)2
USBOE =1
IT5 Schmitt triggered input
IT4E = 1 (ITIFRE)
IT6 Schmitt triggered input
IT5E = 1 (ITIFRE)
IT7 Schmitt triggered input
IT6E = 1 (ITIFRE)
IT8 Schmitt triggered input
IT7E = 1 (ITIFRE)
(MISCR)
push-pull
push-pull
push-pull
State
On SO24 only
31/117
ST7260
Figure 21. Port B Configuration
ALTERNATE ENABLE
ALTERNATE
OUTPUT
VDD
1
0
P-BUFFER
DR
LATCH
VDD
ALTERNATE ENABLE
DDR
PAD
LATCH
DATA BUS
DDR SEL
DIODES
N-BUFFER
DR SEL
1
ALTERNATE ENABLE
0
ALTERNATE INPUT
32/117
DIGITAL ENABLE
VSS
ST7260
I/O PORTS (Cont’d)
9.2.3 Port C
Table 13. Port C Description
I/O
PORT C
Input
1
Alternate Function
Output
Signal
Condition
PC0
with pull-up
push-pull
RDI (SCI input)
PC1
with pull-up
push-pull
TDO (SCI output)
SCI enable
PC22
with pull-up
push-pull
USBOE (USB output enable)
USBOE =1
1
Reset State
2
Not available on SO24
(MISCR)
Figure 22. Port C Configuration
ALTERNATE ENABLE
ALTERNATE 1
OUTPUT
VDD
0
P-BUFFER
DR
PULL-UP
LATCH
VDD
ALTERNATE ENABLE
DATA BUS
DDR
PAD
LATCH
DDR SEL
N-BUFFER
DR SEL
1
0
DIODES
ALTERNATE ENABLE
VSS
ALTERNATE INPUT
CMOS SCHMITT TRIGGER
33/117
ST7260
I/O PORTS (Cont’d)
9.2.4 Register Description
DATA REGISTERS (PxDR)
Port A Data Register (PADR): 0000h
Port B Data Register (PBDR): 0002h
Port C Data Register (PCDR): 0004h
DATA DIRECTION REGISTER (PxDDR)
Port A Data Direction Register (PADDR): 0001h
Port B Data Direction Register (PBDDR): 0003h
Port C Data Direction Register (PCDDR): 0005h
Read/Write
Reset Value Port A: 0000 0000 (00h)
Reset Value Port B: 0000 0000 (00h)
Reset Value Port C: 1111 x000 (FXh)
Read/Write
Reset Value Port A: 0000 0000 (00h)
Reset Value Port B: 0000 0000 (00h)
Reset Value Port C: 1111 x000 (FXh)
Note: For Port C, unused bits (7-3) are not accessible.
Note: For Port C, unused bits (7-3) are not accessible
7
7
0
0
DD7
D7
D6
D5
D4
D3
D2
D1
DD6
DD5
DD4
DD3
DD2
DD1
DD0
D0
Bit 7:0 = D[7:0] Data Register 8 bits.
The DR register has a specific behaviour according to the selected input/output configuration. Writing the DR register is always taken into account
even if the pin is configured as an input. Reading
the DR register returns either the DR register latch
content (pin configured as output) or the digital value applied to the I/O pin (pin configured as input).
Note: When using open-drain I/Os in output configuration, the value read in DR is the digital value
applied to the I/Opin.
Bit 7:0 = DD[7:0] Data Direction Register 8 bits.
The DDR register gives the input/output direction
configuration of the pins. Each bit is set and
cleared by software.
0: Input mode
1: Output mode
Table 14. I/O Ports Register Map
Address
(Hex.)
00
01
02
03
04
05
06
07
Register
Label
7
PADR
PADDR
PBDR
PBDDR
PCDR
PCDDR
MSB
MSB
MSB
MSB
MSB
MSB
6
5
4
2
1
0
LSB
LSB
LSB
LSB
LSB
LSB
Reserved
Reserved
Related Documentation
AN 970: SPI Communication between ST7 and EEPROM
AN1048: Software LCD driver
34/117
3
ST7260
10 MISCELLANEOUS REGISTER
Address: 0009h — Read/Write
Reset Value: 0000 0000 (00h)
7
-
0
-
-
-
-
SMS
USBOE
MCO
Bit 7:3 = Reserved
Bit 2 = SMS Slow Mode Select.
This bit is set by software and only cleared by hardware after a reset. If this bit is set, it enables the use
of an internal divide-by-2 clock divider (refer to Figure 15 on page 22). The SMS bit has no effect on
the USB frequency.
0: Divide-by-2 disabled and CPU clock frequency
is standard
1: Divide-by-2 enabled and CPU clock frequency is
halved.
Bit 1 = USBOE USB enable.
If this bit is set, the port PC2 (PB1 on SO24) outputs the USB output enable signal (at “1” when the
ST7 USB is transmitting data).
Unused bits 7-4 are set.
Bit 0 = MCO Main Clock Out selection
This bit enables the MCO alternate function on the
PA0 I/O port. It is set and cleared by software.
0: MCO alternate function disabled (I/O pin free for
general-purpose I/O)
1: MCO alternate function enabled (fCPU on I/O
port)
35/117
ST7260
11 ON-CHIP PERIPHERALS
11.1 WATCHDOG TIMER (WDG)
11.1.1 Introduction
The Watchdog timer is used to detect the occurrence of a software fault, usually generated by external interference or by unforeseen logical conditions, which causes the application program to
abandon its normal sequence. The Watchdog circuit generates an MCU reset on expiry of a programmed time period, unless the program refreshes the counter’s contents before the T6 bit becomes cleared.
11.1.2 Main Features
■ Programmable
free-running counter (64
increments of 49,152 CPU cycles)
■ Programmable reset
■ Reset (if watchdog activated) when the T6 bit
reaches zero
■ Optional
reset
on
HALT
instruction
(configurable by option byte)
■ Hardware Watchdog selectable by option byte.
11.1.3 Functional Description
The counter value stored in the CR register (bits
T6:T0), is decremented every 49,152 machine cy-
cles, and the length of the timeout period can be
programmed by the user in 64 increments.
If the watchdog is activated (the WDGA bit is set)
and when the 7-bit timer (bits T6:T0) rolls over
from 40h to 3Fh (T6 becomes cleared), it initiates
a reset cycle pulling low the reset pin for typically
30µs.
The application program must write in the CR register at regular intervals during normal operation to
prevent an MCU reset. This downcounter is freerunning: it counts down even if the watchdog is
disabled. The value to be stored in the CR register
must be between FFh and C0h (see Table 15, ".
Watchdog Timing (fCPU = 8 MHz)"):
– The WDGA bit is set (watchdog enabled)
– The T6 bit is set to prevent generating an immediate reset
– The T5:T0 bits contain the number of increments
which represents the time delay before the
watchdog produces a reset.
Figure 23. Watchdog Block Diagram
RESET
WATCHDOG CONTROL REGISTER (CR)
WDGA
T6
T5
T4
T3
T2
7-BIT DOWNCOUNTER
fCPU
36/117
CLOCK DIVIDER
÷49152
T1
T0
ST7260
WATCHDOG TIMER (Cont’d)
Table 15. Watchdog Timing (fCPU = 8 MHz)
CR Register
initial value
WDG timeout period
(ms)
Max
FFh
393.216
Min
C0h
6.144
Notes: Following a reset, the watchdog is disabled. Once activated it cannot be disabled, except
by a reset.
The T6 bit can be used to generate a software reset (the WDGA bit is set and the T6 bit is cleared).
11.1.4 Software Watchdog Option
If Software Watchdog is selected by option byte,
the watchdog is disabled following a reset. Once
activated it cannot be disabled, except by a reset.
The T6 bit can be used to generate a software reset (the WDGA bit is set and the T6 bit is cleared).
11.1.5 Hardware Watchdog Option
If Hardware Watchdog is selected by option byte,
the watchdog is always active and the WDGA bit in
the CR is not used.
11.1.6 Low Power Modes
WAIT Instruction
No effect on Watchdog.
HALT Instruction
If the Watchdog reset on HALT option is selected
by option byte, a HALT instruction causes an immediate reset generation if the Watchdog is activated (WDGA bit is set).
11.1.6.1 Using Halt Mode with the WDG (option)
If the Watchdog reset on HALT option is not selected by option byte, the Halt mode can be used
when the watchdog is enabled.
In this case, the HALT instruction stops the oscillator. When the oscillator is stopped, the WDG stops
counting and is no longer able to generate a reset
until the microcontroller receives an external interrupt or a reset.
If an external interrupt is received, the WDG restarts counting after 4096 CPU clocks. If a reset is
generated, the WDG is disabled (reset state).
Recommendations
– Make sure that an external event is available to
wake up the microcontroller from Halt mode.
– Before executing the HALT instruction, refresh
the WDG counter, to avoid an unexpected WDG
reset immediately after waking up the microcontroller.
– When using an external interrupt to wake up the
microcontroller, reinitialize the corresponding I/O
as “Input Pull-up with Interrupt” before executing
the HALT instruction. The main reason for this is
that the I/O may be wrongly configured due to external interference or by an unforeseen logical
condition.
– For the same reason, reinitialize the level sensitiveness of each external interrupt as a precautionary measure.
– The opcode for the HALT instruction is 0x8E. To
avoid an unexpected HALT instruction due to a
program counter failure, it is advised to clear all
occurrences of the data value 0x8E from memory. For example, avoid defining a constant in
ROM with the value 0x8E.
– As the HALT instruction clears the I bit in the CC
register to allow interrupts, the user may choose
to clear all pending interrupt bits before executing the HALT instruction. This avoids entering
other peripheral interrupt routines after executing
the external interrupt routine corresponding to
the wake-up event (reset or external interrupt).
11.1.7 Interrupts
None.
37/117
ST7260
WATCHDOG TIMER (Cont’d)
11.1.8 Register Description
CONTROL REGISTER (CR)
Read/Write
Reset Value: 0111 1111 (7Fh)
hardware after a reset. When WDGA = 1, the
watchdog can generate a reset.
0: Watchdog disabled
1: Watchdog enabled
7
WDGA
Bit 6:0 = T[6:0] 7-bit timer (MSB to LSB).
These bits contain the decremented value. A reset
is produced when it rolls over from 40h to 3Fh (T6
becomes cleared).
0
T6
T5
T4
T3
T2
T1
T0
Bit 7 = WDGA Activation bit.
This bit is set by software and only cleared by
Table 16. Watchdog Timer Register Map and Reset Values
Address
(Hex.)
0Ch
38/117
Register
Label
7
6
5
4
3
2
1
0
WDGCR
WDGA
T6
T5
T4
T3
T2
T1
T0
Reset Value
0
1
1
1
1
1
1
1
ST7260
11.2 16-BIT TIMER
11.2.1 Introduction
The timer consists of a 16-bit free-running counter
driven by a programmable prescaler.
It may be used for a variety of purposes, including
pulse length measurement of up to two input signals (input capture) or generation of up to two output waveforms (output compare and PWM).
Pulse lengths and waveform periods can be modulated from a few microseconds to several milliseconds using the timer prescaler and the CPU
clock prescaler.
Some ST7 devices have two on-chip 16-bit timers.
They are completely independent, and do not
share any resources. They are synchronized after
a MCU reset as long as the timer clock frequencies are not modified.
This description covers one or two 16-bit timers. In
ST7 devices with two timers, register names are
prefixed with TA (Timer A) or TB (Timer B).
11.2.2 Main Features
■ Programmable prescaler: fCPU divided by 2, 4 or 8
■ Overflow status flag and maskable interrupt
■ External clock input (must be at least four times
slower than the CPU clock speed) with the choice
of active edge
■ 1 or 2 Output Compare functions each with:
– 2 dedicated 16-bit registers
– 2 dedicated programmable signals
– 2 dedicated status flags
– 1 dedicated maskable interrupt
■ 1 or 2 Input Capture functions each with:
– 2 dedicated 16-bit registers
– 2 dedicated active edge selection signals
– 2 dedicated status flags
– 1 dedicated maskable interrupt
■ Pulse width modulation mode (PWM)
■ One Pulse mode
■ Reduced Power Mode
■ 5 alternate functions on I/O ports (ICAP1, ICAP2,
OCMP1, OCMP2, EXTCLK)*
When reading an input signal on a non-bonded
pin, the value will always be ‘1’.
11.2.3 Functional Description
11.2.3.1 Counter
The main block of the Programmable Timer is a
16-bit free running upcounter and its associated
16-bit registers. The 16-bit registers are made up
of two 8-bit registers called high and low.
Counter Register (CR):
– Counter High Register (CHR) is the most significant byte (MS Byte).
– Counter Low Register (CLR) is the least significant byte (LS Byte).
Alternate Counter Register (ACR)
– Alternate Counter High Register (ACHR) is the
most significant byte (MS Byte).
– Alternate Counter Low Register (ACLR) is the
least significant byte (LS Byte).
These two read-only 16-bit registers contain the
same value but with the difference that reading the
ACLR register does not clear the TOF bit (Timer
overflow flag), located in the Status register, (SR),
(see note at the end of paragraph titled 16-bit read
sequence).
Writing in the CLR register or ACLR register resets
the free running counter to the FFFCh value.
Both counters have a reset value of FFFCh (this is
the only value which is reloaded in the 16-bit timer). The reset value of both counters is also
FFFCh in One Pulse mode and PWM mode.
The timer clock depends on the clock control bits
of the CR2 register, as illustrated in Table 17,
"Clock Control Bits". The value in the counter register repeats every 131072, 262144 or 524288
CPU clock cycles depending on the CC[1:0] bits.
The timer frequency can be fCPU/2, fCPU/4, fCPU/8
or an external frequency.
The Block Diagram is shown in Figure 24.
*Note: Some timer pins may not be available (not
bonded) in some ST7 devices. Refer to the device
pin out description.
39/117
ST7260
16-BIT TIMER (Cont’d)
Figure 24. Timer Block Diagram
ST7 INTERNAL BUS
fCPU
MCU-PERIPHERAL INTERFACE
8 low
8
8
8
low
8
high
8
low
8
high
EXEDG
8
low
high
8
high
8-bit
buffer
low
8 high
16
1/2
1/4
1/8
OUTPUT
COMPARE
REGISTER
2
OUTPUT
COMPARE
REGISTER
1
COUNTER
REGISTER
ALTERNATE
COUNTER
REGISTER
EXTCLK
pin
INPUT
CAPTURE
REGISTER
1
INPUT
CAPTURE
REGISTER
2
16
16
16
CC[1:0]
TIMER INTERNAL BUS
16 16
OVERFLOW
DETECT
CIRCUIT
OUTPUT COMPARE
CIRCUIT
6
ICF1 OCF1 TOF ICF2 OCF2 TIMD
0
EDGE DETECT
CIRCUIT1
ICAP1
pin
EDGE DETECT
CIRCUIT2
ICAP2
pin
LATCH1
OCMP1
pin
LATCH2
OCMP2
pin
0
(Control/Status Register)
CSR
ICIE OCIE TOIE FOLV2 FOLV1 OLVL2 IEDG1 OLVL1
(Control Register 1) CR1
OC1E OC2E OPM PWM
CC1
CC0 IEDG2 EXEDG
(Control Register 2) CR2
(See note)
TIMER INTERRUPT
40/117
Note: If IC, OC and TO interrupt requests have separate vectors
then the last OR is not present (See device Interrupt Vector Table)
ST7260
16-BIT TIMER (Cont’d)
16-bit read sequence: (from either the Counter
Register or the Alternate Counter Register).
Beginning of the sequence
At t0
Read
MS Byte
LS Byte
is buffered
Other
instructions
Read
At t0 +∆t LS Byte
Returns the buffered
LS Byte value at t0
Sequence completed
The user must read the MS Byte first, then the LS
Byte value is buffered automatically.
This buffered value remains unchanged until the
16-bit read sequence is completed, even if the
user reads the MS Byte several times.
After a complete reading sequence, if only the
CLR register or ACLR register are read, they return the LS Byte of the count value at the time of
the read.
Whatever the timer mode used (input capture, output compare, One Pulse mode or PWM mode) an
overflow occurs when the counter rolls over from
FFFFh to 0000h then:
– The TOF bit of the SR register is set.
– A timer interrupt is generated if:
– TOIE bit of the CR1 register is set and
– I bit of the CC register is cleared.
If one of these conditions is false, the interrupt remains pending to be issued as soon as they are
both true.
Clearing the overflow interrupt request is done in
two steps:
1. Reading the SR register while the TOF bit is set.
2. An access (read or write) to the CLR register.
Notes: The TOF bit is not cleared by accesses to
ACLR register. The advantage of accessing the
ACLR register rather than the CLR register is that
it allows simultaneous use of the overflow function
and reading the free running counter at random
times (for example, to measure elapsed time) without the risk of clearing the TOF bit erroneously.
The timer is not affected by WAIT mode.
In HALT mode, the counter stops counting until the
mode is exited. Counting then resumes from the
previous count (MCU awakened by an interrupt) or
from the reset count (MCU awakened by a Reset).
11.2.3.2 External Clock
The external clock (where available) is selected if
CC0 = 1 and CC1 = 1 in the CR2 register.
The status of the EXEDG bit in the CR2 register
determines the type of level transition on the external clock pin EXTCLK that will trigger the free running counter.
The counter is synchronized with the falling edge
of the internal CPU clock.
A minimum of four falling edges of the CPU clock
must occur between two consecutive active edges
of the external clock; thus the external clock frequency must be less than a quarter of the CPU
clock frequency.
41/117
ST7260
16-BIT TIMER (Cont’d)
Figure 25. Counter Timing Diagram, Internal Clock Divided by 2
CPU CLOCK
INTERNAL RESET
TIMER CLOCK
COUNTER REGISTER
FFFD FFFE FFFF 0000
0001
0002
0003
TIMER OVERFLOW FLAG (TOF)
Figure 26. Counter Timing Diagram, Internal Clock Divided by 4
CPU CLOCK
INTERNAL RESET
TIMER CLOCK
COUNTER REGISTER
FFFC
FFFD
0000
0001
TIMER OVERFLOW FLAG (TOF)
Figure 27. Counter Timing Diagram, Internal Clock Divided By 8
CPU CLOCK
INTERNAL RESET
TIMER CLOCK
COUNTER REGISTER
FFFC
FFFD
0000
TIMER OVERFLOW FLAG (TOF)
Note: The MCU is in reset state when the internal reset signal is high, when it is low the MCU is running.
42/117
ST7260
16-BIT TIMER (Cont’d)
11.2.3.3 Input Capture
In this section, the index, i, may be 1 or 2 because
there are two input capture functions in the 16-bit
timer.
The two 16-bit input capture registers (IC1R and
IC2R) are used to latch the value of the free running counter after a transition is detected on the
ICAPi pin (see Figure 28).
ICiR
MS Byte
ICiHR
LS Byte
ICiLR
ICiR register is a read-only register.
The active transition is software programmable
through the IEDGi bit of Control Registers (CRi).
Timing resolution is one count of the free running
counter: (fCPU/CC[1:0]).
Procedure:
To use the input capture function select the following in the CR2 register:
– Select the timer clock (CC[1:0]) (see Table 17,
"Clock Control Bits").
– Select the edge of the active transition on the
ICAP2 pin with the IEDG2 bit (the ICAP2 pin
must be configured as floating input or input with
pull-up without interrupt if this configuration is
available).
And select the following in the CR1 register:
– Set the ICIE bit to generate an interrupt after an
input capture coming from either the ICAP1 pin
or the ICAP2 pin
– Select the edge of the active transition on the
ICAP1 pin with the IEDG1 bit (the ICAP1pin must
be configured as floating input or input with pullup without interrupt if this configuration is available).
When an input capture occurs:
– ICFi bit is set.
– The ICiR register contains the value of the free
running counter on the active transition on the
ICAPi pin (see Figure 29).
– A timer interrupt is generated if the ICIE bit is set
and the I bit is cleared in the CC register. Otherwise, the interrupt remains pending until both
conditions become true.
Clearing the Input Capture interrupt request (that
is, clearing the ICFi bit) is done in two steps:
1. Reading the SR register while the ICFi bit is set.
2. An access (read or write) to the ICiLR register.
Notes:
1. After reading the ICiHR register, transfer of
input capture data is inhibited and ICFi will
never be set until the ICiLR register is also
read.
2. The ICiR register contains the free running
counter value which corresponds to the most
recent input capture.
3. The two input capture functions can be used
together even if the timer also uses the two output compare functions.
4. In One Pulse mode and PWM mode only Input
Capture 2 can be used.
5. The alternate inputs (ICAP1 and ICAP2) are
always directly connected to the timer. So any
transitions on these pins activates the input
capture function.
Moreover if one of the ICAPi pins is configured
as an input and the second one as an output,
an interrupt can be generated if the user toggles the output pin and if the ICIE bit is set.
This can be avoided if the input capture function i is disabled by reading the ICiHR (see note
1).
6. The TOF bit can be used with interrupt generation in order to measure events that go beyond
the timer range (FFFFh).
43/117
ST7260
16-BIT TIMER (Cont’d)
Figure 28. Input Capture Block Diagram
ICAP1
pin
ICAP2
pin
(Control Register 1) CR1
EDGE DETECT
CIRCUIT2
EDGE DETECT
CIRCUIT1
ICIE
IEDG1
(Status Register) SR
IC2R Register
IC1R Register
ICF1
ICF2
0
16-BIT FREE RUNNING
COUNTER
CC1
CC0 IEDG2
Figure 29. Input Capture Timing Diagram
TIMER CLOCK
FF01
FF02
FF03
ICAPi PIN
ICAPi FLAG
ICAPi REGISTER
Note: The rising edge is the active edge.
44/117
0
(Control Register 2) CR2
16-BIT
COUNTER REGISTER
0
FF03
ST7260
16-BIT TIMER (Cont’d)
11.2.3.4 Output Compare
In this section, the index, i, may be 1 or 2 because
there are two output compare functions in the 16bit timer.
This function can be used to control an output
waveform or indicate when a period of time has
elapsed.
When a match is found between the Output Compare register and the free running counter, the output compare function:
– Assigns pins with a programmable value if the
OCiE bit is set
– Sets a flag in the status register
– Generates an interrupt if enabled
Two 16-bit registers Output Compare Register 1
(OC1R) and Output Compare Register 2 (OC2R)
contain the value to be compared to the counter
register each timer clock cycle.
OCiR
MS Byte
OCiHR
LS Byte
OCiLR
These registers are readable and writable and are
not affected by the timer hardware. A reset event
changes the OCiR value to 8000h.
Timing resolution is one count of the free running
counter: (fCPU/CC[1:0]).
Procedure:
To use the output compare function, select the following in the CR2 register:
– Set the OCiE bit if an output is needed then the
OCMPi pin is dedicated to the output compare i
signal.
– Select the timer clock (CC[1:0]) (see Table 17,
"Clock Control Bits").
And select the following in the CR1 register:
– Select the OLVLi bit to applied to the OCMPi pins
after the match occurs.
– Set the OCIE bit to generate an interrupt if it is
needed.
When a match is found between OCRi register
and CR register:
– OCFi bit is set.
– The OCMPi pin takes OLVLi bit value (OCMPi
pin latch is forced low during reset).
– A timer interrupt is generated if the OCIE bit is
set in the CR1 register and the I bit is cleared in
the CC register (CC).
The OCiR register value required for a specific timing application can be calculated using the following formula:
∆ OCiR =
∆t * fCPU
PRESC
Where:
∆t
= Output compare period (in seconds)
fCPU
= CPU clock frequency (in hertz)
=
Timer prescaler factor (2, 4 or 8 dePRESC
pending on CC[1:0] bits, see Table 17,
"Clock Control Bits")
If the timer clock is an external clock, the formula
is:
∆ OCiR = ∆t * fEXT
Where:
∆t
= Output compare period (in seconds)
fEXT
= External timer clock frequency (in hertz)
Clearing the output compare interrupt request
(that is, clearing the OCFi bit) is done by:
1. Reading the SR register while the OCFi bit is
set.
2. An access (read or write) to the OCiLR register.
The following procedure is recommended to prevent the OCFi bit from being set between the time
it is read and the write to the OCiR register:
– Write to the OCiHR register (further compares
are inhibited).
– Read the SR register (first step of the clearance
of the OCFi bit, which may be already set).
– Write to the OCiLR register (enables the output
compare function and clears the OCFi bit).
45/117
ST7260
16-BIT TIMER (Cont’d)
Notes:
1. After a processor write cycle to the OCiHR register, the output compare function is inhibited
until the OCiLR register is also written.
2. If the OCiE bit is not set, the OCMPi pin is a
general I/O port and the OLVLi bit will not
appear when a match is found but an interrupt
could be generated if the OCIE bit is set.
3. When the timer clock is fCPU/2, OCFi and
OCMPi are set while the counter value equals
the OCiR register value (see Figure 31 on page
47). This behavior is the same in OPM or PWM
mode.
When the timer clock is fCPU/4, fCPU/8 or in
external clock mode, OCFi and OCMPi are set
while the counter value equals the OCiR register value (see Figure 32 on page 47).
4. The output compare functions can be used both
for generating external events on the OCMPi
pins even if the input capture mode is also
used.
5. The value in the 16-bit OCiR register and the
OLVi bit should be changed after each successful comparison in order to control an output
waveform or establish a new elapsed timeout.
Forced Compare Output capability
When the FOLVi bit is set by software, the OLVLi
bit is copied to the OCMPi pin. The OLVi bit has to
be toggled in order to toggle the OCMPi pin when
it is enabled (OCiE bit = 1). The OCFi bit is then
not set by hardware, and thus no interrupt request
is generated.
The FOLVLi bits have no effect in both One Pulse
mode and PWM mode.
Figure 30. Output Compare Block Diagram
16 BIT FREE RUNNING
COUNTER
OC1E OC2E
CC1
CC0
(Control Register 2) CR2
16-bit
(Control Register 1) CR1
OUTPUT COMPARE
CIRCUIT
16-bit
OCIE
FOLV2 FOLV1 OLVL2
OLVL1
16-bit
Latch
2
OC1R Register
OCF1
OCF2
0
0
0
OC2R Register
(Status Register) SR
46/117
Latch
1
OCMP1
Pin
OCMP2
Pin
ST7260
16-BIT TIMER (Cont’d)
Figure 31. Output Compare Timing Diagram, fTIMER = fCPU/2
INTERNAL CPU CLOCK
TIMER CLOCK
COUNTER REGISTER
2ECF 2ED0
OUTPUT COMPARE REGISTER i (OCRi)
2ED1 2ED2 2ED3 2ED4
2ED3
OUTPUT COMPARE FLAG i (OCFi)
OCMPi PIN (OLVLi = 1)
Figure 32. Output Compare Timing Diagram, fTIMER = fCPU/4
INTERNAL CPU CLOCK
TIMER CLOCK
COUNTER REGISTER
OUTPUT COMPARE REGISTER i (OCRi)
2ECF 2ED0
2ED1 2ED2 2ED3 2ED4
2ED3
COMPARE REGISTER i LATCH
OUTPUT COMPARE FLAG i (OCFi)
OCMPi PIN (OLVLi = 1)
47/117
ST7260
16-BIT TIMER (Cont’d)
11.2.3.5 One Pulse Mode
One Pulse mode enables the generation of a
pulse when an external event occurs. This mode is
selected via the OPM bit in the CR2 register.
The One Pulse mode uses the Input Capture1
function and the Output Compare1 function.
Procedure:
To use One Pulse mode:
1. Load the OC1R register with the value corresponding to the length of the pulse (see the formula in the opposite column).
2. Select the following in the CR1 register:
– Using the OLVL1 bit, select the level to be applied to the OCMP1 pin after the pulse.
– Using the OLVL2 bit, select the level to be applied to the OCMP1 pin during the pulse.
– Select the edge of the active transition on the
ICAP1 pin with the IEDG1 bit (the ICAP1 pin
must be configured as floating input).
3. Select the following in the CR2 register:
– Set the OC1E bit, the OCMP1 pin is then dedicated to the Output Compare 1 function.
– Set the OPM bit.
– Select the timer clock CC[1:0] (see Table 17,
"Clock Control Bits").
One Pulse mode cycle
When
event occurs
on ICAP1
ICR1 = Counter
OCMP1 = OLVL2
Counter is reset
to FFFCh
ICF1 bit is set
When
Counter
= OC1R
OCMP1 = OLVL1
Then, on a valid event on the ICAP1 pin, the counter is initialized to FFFCh and OLVL2 bit is loaded
on the OCMP1 pin, the ICF1 bit is set and the value FFFDh is loaded in the IC1R register.
Because the ICF1 bit is set when an active edge
occurs, an interrupt can be generated if the ICIE
bit is set.
48/117
Clearing the Input Capture interrupt request (that
is, clearing the ICFi bit) is done in two steps:
1. Reading the SR register while the ICFi bit is set.
2. An access (read or write) to the ICiLR register.
The OC1R register value required for a specific
timing application can be calculated using the following formula:
OCiR Value =
t * fCPU
-5
PRESC
Where:
t
= Pulse period (in seconds)
fCPU = CPU clock frequency (in hertz)
PRESC = Timer prescaler factor (2, 4 or 8 depending on the CC[1:0] bits, see Table 17,
"Clock Control Bits")
If the timer clock is an external clock the formula is:
OCiR = t * fEXT -5
Where:
t
= Pulse period (in seconds)
= External timer clock frequency (in hertz)
fEXT
When the value of the counter is equal to the value
of the contents of the OC1R register, the OLVL1
bit is output on the OCMP1 pin, (See Figure 33).
Notes:
1. The OCF1 bit cannot be set by hardware in
One Pulse mode but the OCF2 bit can generate
an Output Compare interrupt.
2. When the Pulse Width Modulation (PWM) and
One Pulse mode (OPM) bits are both set, the
PWM mode is the only active one.
3. If OLVL1 = OLVL2 a continuous signal will be
seen on the OCMP1 pin.
4. The ICAP1 pin can not be used to perform input
capture. The ICAP2 pin can be used to perform
input capture (ICF2 can be set and IC2R can be
loaded) but the user must take care that the
counter is reset each time a valid edge occurs
on the ICAP1 pin and ICF1 can also generates
interrupt if ICIE is set.
5. When One Pulse mode is used OC1R is dedicated to this mode. Nevertheless OC2R and
OCF2 can be used to indicate a period of time
has been elapsed but cannot generate an output waveform because the level OLVL2 is dedicated to the One Pulse mode.
ST7260
16-BIT TIMER (Cont’d)
Figure 33. One Pulse Mode Timing Example
COUNTER
2ED3
01F8
IC1R
01F8
FFFC FFFD FFFE
2ED0 2ED1 2ED2
FFFC FFFD
2ED3
ICAP1
OLVL2
OCMP1
OLVL1
OLVL2
compare1
Note: IEDG1 = 1, OC1R = 2ED0h, OLVL1 = 0, OLVL2 = 1
Figure 34. Pulse Width Modulation Mode Timing Example with 2 Output Compare Functions
2ED0 2ED1 2ED2
COUNTER 34E2 FFFC FFFD FFFE
OLVL2
OCMP1
compare2
OLVL1
compare1
34E2
FFFC
OLVL2
compare2
Note: OC1R = 2ED0h, OC2R = 34E2, OLVL1 = 0, OLVL2 = 1
Note: On timers with only one Output Compare register, a fixed frequency PWM signal can be generated
using the output compare and the counter overflow to define the pulse length.
49/117
ST7260
16-BIT TIMER (Cont’d)
11.2.3.6 Pulse Width Modulation Mode
Pulse Width Modulation (PWM) mode enables the
generation of a signal with a frequency and pulse
length determined by the value of the OC1R and
OC2R registers.
Pulse Width Modulation mode uses the complete
Output Compare 1 function plus the OC2R register, and so this functionality can not be used when
PWM mode is activated.
In PWM mode, double buffering is implemented on
the output compare registers. Any new values written in the OC1R and OC2R registers are taken
into account only at the end of the PWM period
(OC2) to avoid spikes on the PWM output pin
(OCMP1).
Procedure
To use Pulse Width Modulation mode:
1. Load the OC2R register with the value corresponding to the period of the signal using the
formula in the opposite column.
2. Load the OC1R register with the value corresponding to the period of the pulse if
(OLVL1 = 0 and OLVL2 = 1) using the formula
in the opposite column.
3. Select the following in the CR1 register:
– Using the OLVL1 bit, select the level to be applied to the OCMP1 pin after a successful
comparison with the OC1R register.
– Using the OLVL2 bit, select the level to be applied to the OCMP1 pin after a successful
comparison with the OC2R register.
4. Select the following in the CR2 register:
– Set OC1E bit: the OCMP1 pin is then dedicated to the output compare 1 function.
– Set the PWM bit.
– Select the timer clock (CC[1:0]) (see Table 17,
"Clock Control Bits").
Pulse Width Modulation cycle
When
Counter
= OC1R
When
Counter
= OC2R
OCMP1 = OLVL1
OCMP1 = OLVL2
Counter is reset
to FFFCh
ICF1 bit is set
50/117
If OLVL1 = 1 and OLVL2 = 0 the length of the positive pulse is the difference between the OC2R and
OC1R registers.
If OLVL1 = OLVL2 a continuous signal will be
seen on the OCMP1 pin.
The OCiR register value required for a specific timing application can be calculated using the following formula:
OCiR Value =
t * fCPU
-5
PRESC
Where:
t
= Signal or pulse period (in seconds)
fCPU = CPU clock frequency (in hertz)
PRESC = Timer prescaler factor (2, 4 or 8 depending on CC[1:0] bits, see Table 17,
"Clock Control Bits")
If the timer clock is an external clock the formula is:
OCiR = t * fEXT -5
Where:
t
= Signal or pulse period (in seconds)
fEXT
= External timer clock frequency (in hertz)
The Output Compare 2 event causes the counter
to be initialized to FFFCh (See Figure 34)
Notes:
1. After a write instruction to the OCiHR register,
the output compare function is inhibited until the
OCiLR register is also written.
2. The OCF1 and OCF2 bits cannot be set by
hardware in PWM mode therefore the Output
Compare interrupt is inhibited.
3. The ICF1 bit is set by hardware when the counter reaches the OC2R value and can produce a
timer interrupt if the ICIE bit is set and the I bit is
cleared.
4. In PWM mode the ICAP1 pin can not be used
to perform input capture because it is disconnected to the timer. The ICAP2 pin can be used
to perform input capture (ICF2 can be set and
IC2R can be loaded) but the user must take
care that the counter is reset each period and
ICF1 can also generates interrupt if ICIE is set.
5. When the Pulse Width Modulation (PWM) and
One Pulse mode (OPM) bits are both set, the
PWM mode is the only active one.
ST7260
16-BIT TIMER (Cont’d)
11.2.4 Low Power Modes
Mode
WAIT
HALT
Description
No effect on 16-bit Timer.
Timer interrupts cause the device to exit from WAIT mode.
16-bit Timer registers are frozen.
In HALT mode, the counter stops counting until Halt mode is exited. Counting resumes from the previous
count when the MCU is woken up by an interrupt with “exit from HALT mode” capability or from the counter
reset value when the MCU is woken up by a RESET.
If an input capture event occurs on the ICAPi pin, the input capture detection circuitry is armed. Consequently, when the MCU is woken up by an interrupt with “exit from HALT mode” capability, the ICFi bit is set, and
the counter value present when exiting from HALT mode is captured into the ICiR register.
11.2.5 Interrupts
Event
Flag
Interrupt Event
Input Capture 1 event/Counter reset in PWM mode
Input Capture 2 event
Output Compare 1 event (not available in PWM mode)
Output Compare 2 event (not available in PWM mode)
Timer Overflow event
ICF1
ICF2
OCF1
OCF2
TOF
Enable
Control
Bit
Exit
from
Wait
Exit
from
Halt
Yes
No
ICIE
OCIE
TOIE
Note: The 16-bit Timer interrupt events are connected to the same interrupt vector (see Interrupts chapter). These events generate an interrupt if the corresponding Enable Control Bit is set and the interrupt
mask in the CC register is reset (RIM instruction).
11.2.6 Summary of Timer Modes
MODES
Input Capture (1 and/or 2)
Output Compare (1 and/or 2)
One Pulse Mode
PWM Mode
Input Capture 1
TIMER RESOURCES
Input Capture 2
Output Compare 1 Output Compare 2
Yes
Yes
Yes
Yes
No
Not Recommended1)
Not Recommended3)
No
Partially 2)
No
1) See note 4 in Section 11.2.3.5, "One Pulse Mode"
2) See note 5 in Section 11.2.3.5, "One Pulse Mode"
3) See note 4 in Section 11.2.3.6, "Pulse Width Modulation Mode"
51/117
ST7260
16-BIT TIMER (Cont’d)
11.2.7 Register Description
Each Timer is associated with three control and
status registers, and with six pairs of data registers
(16-bit values) relating to the two input captures,
the two output compares, the counter and the alternate counter.
CONTROL REGISTER 1 (CR1)
Read/Write
Reset Value: 0000 0000 (00h)
7
0
Bit 4 = FOLV2 Forced Output Compare 2.
This bit is set and cleared by software.
0: No effect on the OCMP2 pin.
1: Forces the OLVL2 bit to be copied to the
OCMP2 pin, if the OC2E bit is set and even if
there is no successful comparison.
Bit 3 = FOLV1 Forced Output Compare 1.
This bit is set and cleared by software.
0: No effect on the OCMP1 pin.
1: Forces OLVL1 to be copied to the OCMP1 pin, if
the OC1E bit is set and even if there is no successful comparison.
ICIE OCIE TOIE FOLV2 FOLV1 OLVL2 IEDG1 OLVL1
Bit 7 = ICIE Input Capture Interrupt Enable.
0: Interrupt is inhibited.
1: A timer interrupt is generated whenever the
ICF1 or ICF2 bit of the SR register is set.
Bit 6 = OCIE Output Compare Interrupt Enable.
0: Interrupt is inhibited.
1: A timer interrupt is generated whenever the
OCF1 or OCF2 bit of the SR register is set.
Bit 5 = TOIE Timer Overflow Interrupt Enable.
0: Interrupt is inhibited.
1: A timer interrupt is enabled whenever the TOF
bit of the SR register is set.
52/117
Bit 2 = OLVL2 Output Level 2.
This bit is copied to the OCMP2 pin whenever a
successful comparison occurs with the OC2R register and OCxE is set in the CR2 register. This value is copied to the OCMP1 pin in One Pulse mode
and Pulse Width Modulation mode.
Bit 1 = IEDG1 Input Edge 1.
This bit determines which type of level transition
on the ICAP1 pin will trigger the capture.
0: A falling edge triggers the capture.
1: A rising edge triggers the capture.
Bit 0 = OLVL1 Output Level 1.
The OLVL1 bit is copied to the OCMP1 pin whenever a successful comparison occurs with the
OC1R register and the OC1E bit is set in the CR2
register.
ST7260
16-BIT TIMER (Cont’d)
CONTROL REGISTER 2 (CR2)
Read/Write
Reset Value: 0000 0000 (00h)
7
0
OC1E OC2E OPM PWM CC1 CC0 IEDG2 EXEDG
Bit 7 = OC1E Output Compare 1 Pin Enable.
This bit is used only to output the signal from the
timer on the OCMP1 pin (OLV1 in Output Compare mode, both OLV1 and OLV2 in PWM and
one-pulse mode). Whatever the value of the OC1E
bit, the Output Compare 1 function of the timer remains active.
0: OCMP1 pin alternate function disabled (I/O pin
free for general-purpose I/O).
1: OCMP1 pin alternate function enabled.
Bit 6 = OC2E Output Compare 2 Pin Enable.
This bit is used only to output the signal from the
timer on the OCMP2 pin (OLV2 in Output Compare mode). Whatever the value of the OC2E bit,
the Output Compare 2 function of the timer remains active.
0: OCMP2 pin alternate function disabled (I/O pin
free for general-purpose I/O).
1: OCMP2 pin alternate function enabled.
Bit 5 = OPM One Pulse Mode.
0: One Pulse mode is not active.
1: One Pulse mode is active, the ICAP1 pin can be
used to trigger one pulse on the OCMP1 pin; the
active transition is given by the IEDG1 bit. The
length of the generated pulse depends on the
contents of the OC1R register.
Bit 4 = PWM Pulse Width Modulation.
0: PWM mode is not active.
1: PWM mode is active, the OCMP1 pin outputs a
programmable cyclic signal; the length of the
pulse depends on the value of OC1R register;
the period depends on the value of OC2R register.
Bit 3, 2 = CC[1:0] Clock Control.
The timer clock mode depends on these bits:
Table 17. Clock Control Bits
Timer Clock
fCPU / 4
fCPU / 2
fCPU / 8
External Clock (where available)
CC1
0
1
CC0
0
1
0
1
Note: If the external clock pin is not available, programming the external clock configuration stops
the counter.
Bit 1 = IEDG2 Input Edge 2.
This bit determines which type of level transition
on the ICAP2 pin will trigger the capture.
0: A falling edge triggers the capture.
1: A rising edge triggers the capture.
Bit 0 = EXEDG External Clock Edge.
This bit determines which type of level transition
on the external clock pin EXTCLK will trigger the
counter register.
0: A falling edge triggers the counter register.
1: A rising edge triggers the counter register.
53/117
ST7260
16-BIT TIMER (Cont’d)
CONTROL/STATUS REGISTER (CSR)
Read/Write (bits 7:3 read only)
Reset Value: xxxx x0xx (xxh)
Note: Reading or writing the ACLR register does
not clear TOF.
7
ICF1
0
OCF1
TOF
ICF2
OCF2 TIMD
0
0
Bit 7 = ICF1 Input Capture Flag 1.
0: No input capture (reset value).
1: An input capture has occurred on the ICAP1 pin
or the counter has reached the OC2R value in
PWM mode. To clear this bit, first read the SR
register, then read or write the low byte of the
IC1R (IC1LR) register.
Bit 6 = OCF1 Output Compare Flag 1.
0: No match (reset value).
1: The content of the free running counter has
matched the content of the OC1R register. To
clear this bit, first read the SR register, then read
or write the low byte of the OC1R (OC1LR) register.
Bit 5 = TOF Timer Overflow Flag.
0: No timer overflow (reset value).
1: The free running counter rolled over from FFFFh
to 0000h. To clear this bit, first read the SR register, then read or write the low byte of the CR
(CLR) register.
54/117
Bit 4 = ICF2 Input Capture Flag 2.
0: No input capture (reset value).
1: An input capture has occurred on the ICAP2
pin. To clear this bit, first read the SR register,
then read or write the low byte of the IC2R
(IC2LR) register.
Bit 3 = OCF2 Output Compare Flag 2.
0: No match (reset value).
1: The content of the free running counter has
matched the content of the OC2R register. To
clear this bit, first read the SR register, then read
or write the low byte of the OC2R (OC2LR) register.
Bit 2 = TIMD Timer disable.
This bit is set and cleared by software. When set, it
freezes the timer prescaler and counter and disabled the output functions (OCMP1 and OCMP2
pins) to reduce power consumption. Access to the
timer registers is still available, allowing the timer
configuration to be changed, or the counter reset,
while it is disabled.
0: Timer enabled
1: Timer prescaler, counter and outputs disabled
Bits 1:0 = Reserved, must be kept cleared.
ST7260
16-BIT TIMER (Cont’d)
INPUT CAPTURE 1 HIGH REGISTER (IC1HR)
Read Only
Reset Value: Undefined
This is an 8-bit read only register that contains the
high part of the counter value (transferred by the
input capture 1 event).
OUTPUT COMPARE 1 HIGH REGISTER
(OC1HR)
Read/Write
Reset Value: 1000 0000 (80h)
This is an 8-bit register that contains the high part
of the value to be compared to the CHR register.
7
0
7
0
MSB
LSB
MSB
LSB
INPUT CAPTURE 1 LOW REGISTER (IC1LR)
Read Only
Reset Value: Undefined
This is an 8-bit read only register that contains the
low part of the counter value (transferred by the input capture 1 event).
OUTPUT COMPARE 1 LOW REGISTER
(OC1LR)
Read/Write
Reset Value: 0000 0000 (00h)
This is an 8-bit register that contains the low part of
the value to be compared to the CLR register.
7
0
7
0
MSB
LSB
MSB
LSB
55/117
ST7260
16-BIT TIMER (Cont’d)
OUTPUT COMPARE 2 HIGH REGISTER
(OC2HR)
Read/Write
Reset Value: 1000 0000 (80h)
This is an 8-bit register that contains the high part
of the value to be compared to the CHR register.
ALTERNATE COUNTER HIGH REGISTER
(ACHR)
Read Only
Reset Value: 1111 1111 (FFh)
This is an 8-bit register that contains the high part
of the counter value.
7
0
7
0
MSB
LSB
MSB
LSB
OUTPUT COMPARE 2 LOW REGISTER
(OC2LR)
Read/Write
Reset Value: 0000 0000 (00h)
This is an 8-bit register that contains the low part of
the value to be compared to the CLR register.
7
0
MSB
LSB
COUNTER HIGH REGISTER (CHR)
Read Only
Reset Value: 1111 1111 (FFh)
This is an 8-bit register that contains the high part
of the counter value.
7
0
MSB
LSB
COUNTER LOW REGISTER (CLR)
Read Only
Reset Value: 1111 1100 (FCh)
This is an 8-bit register that contains the low part of
the counter value. A write to this register resets the
counter. An access to this register after accessing
the CSR register clears the TOF bit.
7
0
MSB
LSB
56/117
ALTERNATE COUNTER LOW REGISTER
(ACLR)
Read Only
Reset Value: 1111 1100 (FCh)
This is an 8-bit register that contains the low part of
the counter value. A write to this register resets the
counter. An access to this register after an access
to CSR register does not clear the TOF bit in the
CSR register.
7
0
MSB
LSB
INPUT CAPTURE 2 HIGH REGISTER (IC2HR)
Read Only
Reset Value: Undefined
This is an 8-bit read only register that contains the
high part of the counter value (transferred by the
Input Capture 2 event).
7
0
MSB
LSB
INPUT CAPTURE 2 LOW REGISTER (IC2LR)
Read Only
Reset Value: Undefined
This is an 8-bit read only register that contains the
low part of the counter value (transferred by the Input Capture 2 event).
7
0
MSB
LSB
ST7260
16-BIT TIMER (Cont’d)
Table 18. 16-Bit Timer Register Map and Reset Values
Address
(Hex.)
11
12
13
14
15
16
17
18
19
1A
1B
1C
1D
1E
1F
Register
Label
7
6
5
4
3
2
1
0
OC1E
OC2E
OPM
PWM
CC1
CC0
IEDG2
EXEDG
Reset Value
CR1
0
ICIE
0
OCIE
0
TOIE
0
FOLV2
0
FOLV1
0
OLVL2
0
IEDG1
0
OLVL1
Reset Value
CSR
0
ICF1
0
OCF1
0
TOF
0
ICF2
0
OCF2
0
TIMD
0
0
0
0
Reset Value
IC1HR
0
0
0
0
0
0
0
0
CR2
Reset Value
IC1LR
Reset Value
OC1HR
Reset Value
OC1LR
Reset Value
CHR
Reset Value
CLR
Reset Value
ACHR
Reset Value
ACLR
Reset Value
IC2HR
Reset Value
IC2LR
Reset Value
OC2HR
Reset Value
OC2LR
Reset Value
MSB
LSB
MSB
LSB
MSB
1
0
0
0
0
0
0
LSB
0
MSB
0
0
0
0
0
0
0
LSB
0
MSB
1
1
1
1
1
1
1
LSB
1
MSB
1
1
1
1
1
1
0
LSB
0
MSB
1
1
1
1
1
1
1
LSB
1
MSB
1
1
1
1
1
1
0
LSB
0
MSB
LSB
MSB
LSB
MSB
1
0
0
0
0
0
0
LSB
0
MSB
0
0
0
0
0
0
0
LSB
0
57/117
ST7260
11.3 SERIAL COMMUNICATIONS INTERFACE (SCI)
11.3.1 Introduction
The Serial Communications Interface (SCI) offers
a flexible means of full-duplex data exchange with
external equipment requiring an industry standard
NRZ asynchronous serial data format. The SCI offers a very wide range of baud rates using two
baud rate generator systems.
11.3.2 Main Features
■ Full duplex, asynchronous communications
■ NRZ standard format (Mark/Space)
■ Independently
programmable transmit and
receive baud rates up to 250K baud.
■ Programmable data word length (8 or 9 bits)
■ Receive buffer full, Transmit buffer empty and
End of Transmission flags
■ Two receiver wake-up modes:
– Address bit (MSB)
– Idle line
■ Muting function for multiprocessor configurations
■ Separate enable bits for Transmitter and
Receiver
■ Four error detection flags:
– Overrun error
– Noise error
– Frame error
– Parity error
■ Six interrupt sources with flags:
– Transmit data register empty
– Transmission complete
– Receive data register full
– Idle line received
– Overrun error detected
– Parity error
■ Parity control:
– Transmits parity bit
– Checks parity of received data byte
■ Reduced power consumption mode
58/117
11.3.3 General Description
The interface is externally connected to another
device by two pins (see Figure 36):
– TDO: Transmit Data Output. When the transmitter and the receiver are disabled, the output pin
returns to its I/O port configuration. When the
transmitter and/or the receiver are enabled and
nothing is to be transmitted, the TDO pin is at
high level.
– RDI: Receive Data Input is the serial data input.
Oversampling techniques are used for data recovery by discriminating between valid incoming
data and noise.
Through these pins, serial data is transmitted and
received as frames comprising:
– An Idle Line prior to transmission or reception
– A start bit
– A data word (8 or 9 bits) least significant bit first
– A Stop bit indicating that the frame is complete.
This interface uses two types of baud rate generator:
– A conventional type for commonly-used baud
rates.
ST7260
SERIAL COMMUNICATIONS INTERFACE (Cont’d)
Figure 35. SCI Block Diagram
Write
Read
(DATA REGISTER) DR
Received Data Register (RDR)
Transmit Data Register (TDR)
TDO
Received Shift Register
Transmit Shift Register
RDI
CR1
R8
TRANSMIT
WAKE
UP
CONTROL
UNIT
T8
SCID
M WAKE PCE PS
PIE
RECEIVER
CLOCK
RECEIVER
CONTROL
CR2
SR
TIE TCIE RIE
ILIE
TE
RE RWU SBK
TDRE TC RDRF IDLE OR
NF
FE
PE
SCI
INTERRUPT
CONTROL
TRANSMITTER
CLOCK
TRANSMITTER RATE
fCPU
CONTROL
/16
/PR
BRR
SCP1 SCP0 SCT2 SCT1 SCT0 SCR2 SCR1SCR0
RECEIVER RATE
CONTROL
BAUD RATE GENERATOR
59/117
ST7260
SERIAL COMMUNICATIONS INTERFACE (Cont’d)
11.3.4 Functional Description
The block diagram of the Serial Control Interface,
is shown in Figure 35 It contains 6 dedicated registers:
– Two control registers (SCICR1 & SCICR2)
– A status register (SCISR)
– A baud rate register (SCIBRR)
Refer to the register descriptions in Section 11.3.7
for the definitions of each bit.
11.3.4.1 Serial Data Format
Word length may be selected as being either 8 or 9
bits by programming the M bit in the SCICR1 register (see Figure 35).
The TDO pin is in low state during the start bit.
The TDO pin is in high state during the stop bit.
An Idle character is interpreted as an entire frame
of “1”s followed by the start bit of the next frame
which contains data.
A Break character is interpreted on receiving “0”s
for some multiple of the frame period. At the end of
the last break frame the transmitter inserts an extra “1” bit to acknowledge the start bit.
Transmission and reception are driven by their
own baud rate generator.
Figure 36. Word Length Programming
9-bit Word length (M bit is set)
Possible
Parity
Bit
Data Frame
Start
Bit
Bit0
Bit2
Bit1
Bit3
Bit4
Bit5
Bit6
Start
Bit
Break Frame
Extra
’1’
Possible
Parity
Bit
Data Frame
60/117
Bit0
Bit8
Next
Stop Start
Bit
Bit
Idle Frame
8-bit Word length (M bit is reset)
Start
Bit
Bit7
Next Data Frame
Bit1
Bit2
Bit3
Bit4
Bit5
Bit6
Bit7
Start
Bit
Next Data Frame
Stop
Bit
Next
Start
Bit
Idle Frame
Start
Bit
Break Frame
Extra Start
Bit
’1’
ST7260
SERIAL COMMUNICATIONS INTERFACE (Cont’d)
11.3.4.2 Transmitter
The transmitter can send data words of either 8 or
9 bits depending on the M bit status. When the M
bit is set, word length is 9 bits and the 9th bit (the
MSB) has to be stored in the T8 bit in the SCICR1
register.
Character Transmission
During an SCI transmission, data shifts out least
significant bit first on the TDO pin. In this mode,
the SCIDR register consists of a buffer (TDR) between the internal bus and the transmit shift register (see Figure 35).
Procedure
– Select the M bit to define the word length.
– Select the desired baud rate using the SCIBRR
and the SCIETPR registers.
– Set the TE bit to assign the TDO pin to the alternate function and to send a idle frame as first
transmission.
– Access the SCISR register and write the data to
send in the SCIDR register (this sequence clears
the TDRE bit). Repeat this sequence for each
data to be transmitted.
Clearing the TDRE bit is always performed by the
following software sequence:
1. An access to the SCISR register
2. A write to the SCIDR register
The TDRE bit is set by hardware and it indicates:
– The TDR register is empty.
– The data transfer is beginning.
– The next data can be written in the SCIDR register without overwriting the previous data.
This flag generates an interrupt if the TIE bit is set
and the I bit is cleared in the CCR register.
When a transmission is taking place, a write instruction to the SCIDR register stores the data in
the TDR register and which is copied in the shift
register at the end of the current transmission.
When no transmission is taking place, a write instruction to the SCIDR register places the data directly in the shift register, the data transmission
starts, and the TDRE bit is immediately set.
When a frame transmission is complete (after the
stop bit or after the break frame) the TC bit is set
and an interrupt is generated if the TCIE is set and
the I bit is cleared in the CCR register.
Clearing the TC bit is performed by the following
software sequence:
1. An access to the SCISR register
2. A write to the SCIDR register
Note: The TDRE and TC bits are cleared by the
same software sequence.
Break Characters
Setting the SBK bit loads the shift register with a
break character. The break frame length depends
on the M bit (see Figure 36).
As long as the SBK bit is set, the SCI send break
frames to the TDO pin. After clearing this bit by
software the SCI insert a logic 1 bit at the end of
the last break frame to guarantee the recognition
of the start bit of the next frame.
Idle Characters
Setting the TE bit drives the SCI to send an idle
frame before the first data frame.
Clearing and then setting the TE bit during a transmission sends an idle frame after the current word.
Note: Resetting and setting the TE bit causes the
data in the TDR register to be lost. Therefore the
best time to toggle the TE bit is when the TDRE bit
is set i.e. before writing the next byte in the SCIDR.
61/117
ST7260
SERIAL COMMUNICATIONS INTERFACE (Cont’d)
11.3.4.3 Receiver
The SCI can receive data words of either 8 or 9
bits. When the M bit is set, word length is 9 bits
and the MSB is stored in the R8 bit in the SCICR1
register.
Character reception
During a SCI reception, data shifts in least significant bit first through the RDI pin. In this mode, the
SCIDR register consists or a buffer (RDR) between the internal bus and the received shift register (see Figure 35).
Procedure
– Select the M bit to define the word length.
– Select the desired baud rate using the SCIBRR
and the SCIERPR registers.
– Set the RE bit, this enables the receiver which
begins searching for a start bit.
When a character is received:
– The RDRF bit is set. It indicates that the content
of the shift register is transferred to the RDR.
– An interrupt is generated if the RIE bit is set and
the I bit is cleared in the CCR register.
– The error flags can be set if a frame error, noise
or an overrun error has been detected during reception.
Clearing the RDRF bit is performed by the following
software sequence done by:
1. An access to the SCISR register
2. A read to the SCIDR register.
The RDRF bit must be cleared before the end of the
reception of the next character to avoid an overrun
error.
Break Character
When a break character is received, the SCI handles it as a framing error.
Idle Character
When a idle frame is detected, there is the same
procedure as a data received character plus an interrupt if the ILIE bit is set and the I bit is cleared in
the CCR register.
Overrun Error
An overrun error occurs when a character is received when RDRF has not been reset. Data can
not be transferred from the shift register to the
62/117
RDR register as long as the RDRF bit is not
cleared.
When a overrun error occurs:
– The OR bit is set.
– The RDR content will not be lost.
– The shift register will be overwritten.
– An interrupt is generated if the RIE bit is set and
the I bit is cleared in the CCR register.
The OR bit is reset by an access to the SCISR register followed by a SCIDR register read operation.
Noise Error
Oversampling techniques are used for data recovery by discriminating between valid incoming data
and noise. Normal data bits are considered valid if
three consecutive samples (8th, 9th, 10th) have
the same bit value, otherwise the NF flag is set. In
the case of start bit detection, the NF flag is set on
the basis of an algorithm combining both valid
edge detection and three samples (8th, 9th, 10th).
Therefore, to prevent the NF flag getting set during
start bit reception, there should be a valid edge detection as well as three valid samples.
When noise is detected in a frame:
– The NF flag is set at the rising edge of the RDRF
bit.
– Data is transferred from the Shift register to the
SCIDR register.
– No interrupt is generated. However this bit rises
at the same time as the RDRF bit which itself
generates an interrupt.
The NF flag is reset by a SCISR register read operation followed by a SCIDR register read operation.
During reception, if a false start bit is detected (e.g.
8th, 9th, 10th samples are 011,101,110), the
frame is discarded and the receiving sequence is
not started for this frame. There is no RDRF bit set
for this frame and the NF flag is set internally (not
accessible to the user). This NF flag is accessible
along with the RDRF bit when a next valid frame is
received.
Note: If the application Start Bit is not long enough
to match the above requirements, then the NF
Flag may get set due to the short Start Bit. In this
case, the NF flag may be ignored by the application software when the first valid byte is received.
See also Section 11.3.4.9.
ST7260
SERIAL COMMUNICATIONS INTERFACE (Cont’d)
Framing Error
A framing error is detected when:
– The stop bit is not recognized on reception at the
expected time, following either a de-synchronization or excessive noise.
– A break is received.
When the framing error is detected:
– the FE bit is set by hardware
– Data is transferred from the Shift register to the
SCIDR register.
– No interrupt is generated. However this bit rises
at the same time as the RDRF bit which itself
generates an interrupt.
The FE bit is reset by a SCISR register read operation followed by a SCIDR register read operation.
11.3.4.4 Baud Rate Generation
The baud rate for the receiver and transmitter (Rx
and Tx) are set independently and calculated as
follows:
Tx =
fCPU
(16*PR)*TR
Rx =
fCPU
(16*PR)*RR
with:
PR = 1, 3, 4 or 13 (see SCP[1:0] bits)
TR = 1, 2, 4, 8, 16, 32, 64,128
(see SCT[2:0] bits)
RR = 1, 2, 4, 8, 16, 32, 64,128
(see SCR[2:0] bits)
All these bits are in the SCIBRR register.
Example: If fCPU is 8 MHz (normal mode) and if
PR=13 and TR=RR=1, the transmit and receive
baud rates are 38400 baud.
Note: the baud rate registers MUST NOT be
changed while the transmitter or the receiver is enabled.
11.3.4.5 Receiver Muting and Wake-up Feature
In multiprocessor configurations it is often desirable that only the intended message recipient
should actively receive the full message contents,
thus reducing redundant SCI service overhead for
all non addressed receivers.
The non addressed devices may be placed in
sleep mode by means of the muting function.
Setting the RWU bit by software puts the SCI in
sleep mode:
All the reception status bits can not be set.
All the receive interrupts are inhibited.
A muted receiver may be awakened by one of the
following two ways:
– by Idle Line detection if the WAKE bit is reset,
– by Address Mark detection if the WAKE bit is set.
Receiver wakes-up by Idle Line detection when
the Receive line has recognised an Idle Frame.
Then the RWU bit is reset by hardware but the
IDLE bit is not set.
Receiver wakes-up by Address Mark detection
when it received a “1” as the most significant bit of
a word, thus indicating that the message is an address. The reception of this particular word wakes
up the receiver, resets the RWU bit and sets the
RDRF bit, which allows the receiver to receive this
word normally and to use it as an address word.
Caution: In Mute mode, do not write to the
SCICR2 register. If the SCI is in Mute mode during
the read operation (RWU=1) and a address mark
wake up event occurs (RWU is reset) before the
write operation, the RWU bit will be set again by
this write operation. Consequently the address
byte is lost and the SCI is not woken up from Mute
mode.
63/117
ST7260
SERIAL COMMUNICATIONS INTERFACE (Cont’d)
11.3.4.6 Parity Control
Parity control (generation of parity bit in transmission and parity checking in reception) can be enabled by setting the PCE bit in the SCICR1 register.
Depending on the frame length defined by the M
bit, the possible SCI frame formats are as listed in
Table 19.
Table 19. Frame Formats
M bit
0
0
1
1
PCE bit
0
1
0
1
SCI frame
| SB | 8 bit data | STB |
| SB | 7-bit data | PB | STB |
| SB | 9-bit data | STB |
| SB | 8-bit data PB | STB |
Legend: SB = Start Bit, STB = Stop Bit,
PB = Parity Bit
Note: In case of wake up by an address mark, the
MSB bit of the data is taken into account and not
the parity bit
Even parity: the parity bit is calculated to obtain
an even number of “1s” inside the frame made of
the 7 or 8 LSB bits (depending on whether M is
equal to 0 or 1) and the parity bit.
Ex: data=00110101; 4 bits set => parity bit will be
0 if even parity is selected (PS bit = 0).
Odd parity: the parity bit is calculated to obtain an
odd number of “1s” inside the frame made of the 7
or 8 LSB bits (depending on whether M is equal to
0 or 1) and the parity bit.
Ex: data=00110101; 4 bits set => parity bit will be
1 if odd parity is selected (PS bit = 1).
Transmission mode: If the PCE bit is set then the
MSB bit of the data written in the data register is
not transmitted but is changed by the parity bit.
Reception mode: If the PCE bit is set then the interface checks if the received data byte has an
64/117
even number of “1s” if even parity is selected
(PS=0) or an odd number of “1s” if odd parity is selected (PS=1). If the parity check fails, the PE flag
is set in the SCISR register and an interrupt is generated if PIE is set in the SCICR1 register.
11.3.4.7 SCI Clock Tolerance
During reception, each bit is sampled 16 times.
The majority of the 8th, 9th and 10th samples is
considered as the bit value. For a valid bit detection, all the three samples should have the same
value otherwise the noise flag (NF) is set. For example: if the 8th, 9th and 10th samples are 0, 1
and 1 respectively, then the bit value will be “1”,
but the Noise Flag bit is be set because the three
samples values are not the same.
Consequently, the bit length must be long enough
so that the 8th, 9th and 10th samples have the desired bit value. This means the clock frequency
should not vary more than 6/16 (37.5%) within one
bit. The sampling clock is resynchronized at each
start bit, so that when receiving 10 bits (one start
bit, 1 data byte, 1 stop bit), the clock deviation
must not exceed 3.75%.
Note: The internal sampling clock of the microcontroller samples the pin value on every falling edge.
Therefore, the internal sampling clock and the time
the application expects the sampling to take place
may be out of sync. For example: If the baud rate
is 15.625 kbaud (bit length is 64µs), then the 8th,
9th and 10th samples will be at 28µs, 32µs & 36µs
respectively (the first sample starting ideally at
0µs). But if the falling edge of the internal clock occurs just before the pin value changes, the samples would then be out of sync by ~4us. This
means the entire bit length must be at least 40µs
(36µs for the 10th sample + 4µs for synchronization with the internal sampling clock).
ST7260
SERIAL COMMUNICATIONS INTERFACE (Cont’d)
11.3.4.8 Clock Deviation Causes
The causes which contribute to the total deviation
are:
– DTRA: Deviation due to transmitter error (Local
oscillator error of the transmitter or the transmitter is transmitting at a different baud rate).
– DQUANT: Error due to the baud rate quantisation of the receiver.
– DREC: Deviation of the local oscillator of the
receiver: This deviation can occur during the
reception of one complete SCI message assuming that the deviation has been compensated at the beginning of the message.
– DTCL: Deviation due to the transmission line
(generally due to the transceivers)
All the deviations of the system should be added
and compared to the SCI clock tolerance:
DTRA + DQUANT + DREC + DTCL < 3.75%
11.3.4.9 Noise Error Causes
See also description of Noise error in Section
11.3.4.3.
Start bit
The noise flag (NF) is set during start bit reception
if one of the following conditions occurs:
1. A valid falling edge is not detected. A falling
edge is considered to be valid if the 3 consecutive samples before the falling edge occurs are
detected as '1' and, after the falling edge
occurs, during the sampling of the 16 samples,
if one of the samples numbered 3, 5 or 7 is
detected as a “1”.
2. During sampling of the 16 samples, if one of the
samples numbered 8, 9 or 10 is detected as a
“1”.
Therefore, a valid Start Bit must satisfy both the
above conditions to prevent the Noise Flag getting
set.
Data Bits
The noise flag (NF) is set during normal data bit reception if the following condition occurs:
– During the sampling of 16 samples, if all three
samples numbered 8, 9 and10 are not the same.
The majority of the 8th, 9th and 10th samples is
considered as the bit value.
Therefore, a valid Data Bit must have samples 8, 9
and 10 at the same value to prevent the Noise
Flag getting set.
Figure 37. Bit Sampling in Reception Mode
RDI LINE
sampled values
Sample
clock
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
6/16
7/16
7/16
One bit time
65/117
ST7260
SERIAL COMMUNICATIONS INTERFACE (Cont’d)
11.3.5 Low Power Modes
Mode
Description
No effect on SCI.
WAIT
SCI interrupts cause the device to exit
from Wait mode.
SCI registers are frozen.
HALT
In Halt mode, the SCI stops transmitting/receiving until Halt mode is exited.
11.3.6 Interrupts
The SCI interrupt events are connected to the
same interrupt vector.
These events generate an interrupt if the corresponding Enable Control Bit is set and the inter-
66/117
Interrupt Event
Enable Exit
Event
Control from
Flag
Bit
Wait
Transmit Data Register
TDRE
Empty
Transmission ComTC
plete
Received Data Ready
RDRF
to be Read
Overrun Error Detected OR
Idle Line Detected
IDLE
Parity Error
PE
Exit
from
Halt
TIE
Yes
No
TCIE
Yes
No
Yes
No
Yes
Yes
Yes
No
No
No
RIE
ILIE
PIE
rupt mask in the CC register is reset (RIM instruction).
ST7260
SERIAL COMMUNICATIONS INTERFACE (Cont’d)
11.3.7 Register Description
Note: The IDLE bit will not be set again until the
RDRF bit has been set itself (i.e. a new idle line ocSTATUS REGISTER (SCISR)
curs).
Read Only
Reset Value: 1100 0000 (C0h)
Bit 3 = OR Overrun error.
7
0
This bit is set by hardware when the word currently
being received in the shift register is ready to be
TDRE
TC
RDRF IDLE
OR
NF
FE
PE
transferred into the RDR register while RDRF=1.
An interrupt is generated if RIE=1 in the SCICR2
register. It is cleared by a software sequence (an
Bit 7 = TDRE Transmit data register empty.
access to the SCISR register followed by a read to
This bit is set by hardware when the content of the
the SCIDR register).
TDR register has been transferred into the shift
0: No Overrun error
register. An interrupt is generated if the TIE bit=1
1: Overrun error is detected
in the SCICR2 register. It is cleared by a software
sequence (an access to the SCISR register folNote: When this bit is set RDR register content will
lowed by a write to the SCIDR register).
not be lost but the shift register will be overwritten.
0: Data is not transferred to the shift register
1: Data is transferred to the shift register
Bit 2 = NF Noise flag.
Note: Data will not be transferred to the shift regThis bit is set by hardware when noise is detected
ister unless the TDRE bit is cleared.
on a received frame. It is cleared by a software sequence (an access to the SCISR register followed
by a read to the SCIDR register).
Bit 6 = TC Transmission complete.
0: No noise is detected
This bit is set by hardware when transmission of a
1: Noise is detected
frame containing Data is complete. An interrupt is
generated if TCIE=1 in the SCICR2 register. It is
Note: This bit does not generate interrupt as it apcleared by a software sequence (an access to the
pears at the same time as the RDRF bit which itSCISR register followed by a write to the SCIDR
self generates an interrupt.
register).
0: Transmission is not complete
1: Transmission is complete
Bit 1 = FE Framing error.
This bit is set by hardware when a de-synchronizaNote: TC is not set after the transmission of a Pretion, excessive noise or a break character is deamble or a Break.
tected. It is cleared by a software sequence (an
access to the SCISR register followed by a read to
Bit 5 = RDRF Received data ready flag.
the SCIDR register).
This bit is set by hardware when the content of the
0: No Framing error is detected
RDR register has been transferred to the SCIDR
1: Framing error or break character is detected
register. An interrupt is generated if RIE=1 in the
Note: This bit does not generate interrupt as it apSCICR2 register. It is cleared by a software sepears at the same time as the RDRF bit which itquence (an access to the SCISR register followed
self generates an interrupt. If the word currently
by a read to the SCIDR register).
being transferred causes both frame error and
0: Data is not received
overrun error, it will be transferred and only the OR
1: Received data is ready to be read
bit will be set.
Bit 4 = IDLE Idle line detect.
This bit is set by hardware when a Idle Line is detected. An interrupt is generated if the ILIE=1 in
the SCICR2 register. It is cleared by a software sequence (an access to the SCISR register followed
by a read to the SCIDR register).
0: No Idle Line is detected
1: Idle Line is detected
Bit 0 = PE Parity error.
This bit is set by hardware when a parity error occurs in receiver mode. It is cleared by a software
sequence (a read to the status register followed by
an access to the SCIDR data register). An interrupt is generated if PIE=1 in the SCICR1 register.
0: No parity error
1: Parity error
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ST7260
SERIAL COMMUNICATIONS INTERFACE (Cont’d)
CONTROL REGISTER 1 (SCICR1)
Read/Write
Bit 3 = WAKE Wake-Up method.
This bit determines the SCI Wake-Up method, it is
Reset Value: x000 0000 (x0h)
set or cleared by software.
0: Idle Line
7
0
1: Address Mark
R8
T8
SCID
M
WAKE
PCE
PS
PIE
Bit 7 = R8 Receive data bit 8.
This bit is used to store the 9th bit of the received
word when M=1.
Bit 6 = T8 Transmit data bit 8.
This bit is used to store the 9th bit of the transmitted word when M=1.
Bit 5 = SCID Disabled for low power consumption
When this bit is set the SCI prescalers and outputs
are stopped and the end of the current byte transfer in order to reduce power consumption.This bit
is set and cleared by software.
0: SCI enabled
1: SCI prescaler and outputs disabled
Bit 4 = M Word length.
This bit determines the word length. It is set or
cleared by software.
0: 1 Start bit, 8 Data bits, 1 Stop bit
1: 1 Start bit, 9 Data bits, 1 Stop bit
Note: The M bit must not be modified during a data
transfer (both transmission and reception).
68/117
Bit 2 = PCE Parity control enable.
This bit selects the hardware parity control (generation and detection). When the parity control is enabled, the computed parity is inserted at the MSB
position (9th bit if M=1; 8th bit if M=0) and parity is
checked on the received data. This bit is set and
cleared by software. Once it is set, PCE is active
after the current byte (in reception and in transmission).
0: Parity control disabled
1: Parity control enabled
Bit 1 = PS Parity selection.
This bit selects the odd or even parity when the
parity generation/detection is enabled (PCE bit
set). It is set and cleared by software. The parity
will be selected after the current byte.
0: Even parity
1: Odd parity
Bit 0 = PIE Parity interrupt enable.
This bit enables the interrupt capability of the hardware parity control when a parity error is detected
(PE bit set). It is set and cleared by software.
0: Parity error interrupt disabled
1: Parity error interrupt enabled.
ST7260
SERIAL COMMUNICATIONS INTERFACE (Cont’d)
CONTROL REGISTER 2 (SCICR2)
Notes:
Read/Write
– During transmission, a “0” pulse on the TE bit
(“0” followed by “1”) sends a preamble (idle line)
Reset Value: 0000 0000 (00h)
after the current word.
7
0
– When TE is set there is a 1 bit-time delay before
the transmission starts.
TIE
TCIE
RIE
ILIE
TE
RE
RWU SBK
Caution: The TDO pin is free for general purpose
I/O only when the TE and RE bits are both cleared
(or if TE is never set).
Bit 7 = TIE Transmitter interrupt enable.
This bit is set and cleared by software.
0: Interrupt is inhibited
Bit 2 = RE Receiver enable.
1: An SCI interrupt is generated whenever
This bit enables the receiver. It is set and cleared
TDRE=1 in the SCISR register
by software.
0: Receiver is disabled
Bit 6 = TCIE Transmission complete interrupt ena1: Receiver is enabled and begins searching for a
ble
start bit
This bit is set and cleared by software.
0: Interrupt is inhibited
Bit 1 = RWU Receiver wake-up.
1: An SCI interrupt is generated whenever TC=1 in
This bit determines if the SCI is in mute mode or
the SCISR register
not. It is set and cleared by software and can be
cleared by hardware when a wake-up sequence is
Bit 5 = RIE Receiver interrupt enable.
recognized.
This bit is set and cleared by software.
0: Receiver in Active mode
0: Interrupt is inhibited
1: Receiver in Mute mode
1: An SCI interrupt is generated whenever OR=1
Note: Before selecting Mute mode (setting the
or RDRF=1 in the SCISR register
RWU bit), the SCI must receive some data first,
otherwise it cannot function in Mute mode with
Bit 4 = ILIE Idle line interrupt enable.
wakeup by idle line detection.
This bit is set and cleared by software.
0: Interrupt is inhibited
Bit 0 = SBK Send break.
1: An SCI interrupt is generated whenever IDLE=1
This bit set is used to send break characters. It is
in the SCISR register.
set and cleared by software.
Bit 3 = TE Transmitter enable.
This bit enables the transmitter. It is set and
cleared by software.
0: Transmitter is disabled
1: Transmitter is enabled
0: No break character is transmitted
1: Break characters are transmitted
Note: If the SBK bit is set to “1” and then to “0”, the
transmitter will send a BREAK word at the end of
the current word.
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ST7260
SERIAL COMMUNICATIONS INTERFACE (Cont’d)
DATA REGISTER (SCIDR)
PR Prescaling factor
SCP1
SCP0
Read/Write
4
1
0
Reset Value: Undefined
13
1
1
Contains the Received or Transmitted data character, depending on whether it is read from or writBits 5:3 = SCT[2:0] SCI Transmitter rate divisor
ten to.
These 3 bits, in conjunction with the SCP1 & SCP0
bits define the total division applied to the bus
7
0
clock to yield the transmit rate clock.
DR7
DR6
DR5
DR4
DR3
DR2
DR1
DR0
The Data register performs a double function (read
and write) since it is composed of two registers,
one for transmission (TDR) and one for reception
(RDR).
The TDR register provides the parallel interface
between the internal bus and the output shift register (see Figure 35).
The RDR register provides the parallel interface
between the input shift register and the internal
bus (see Figure 35).
7
0
SCP0
SCT2
SCT1
SCT0
SCR2
SCR1 SCR0
Bits 7:6= SCP[1:0] First SCI Prescaler
These 2 prescaling bits allow several standard
clock division ranges:
PR Prescaling factor
70/117
SCP1
SCT2
SCT1
SCT0
1
0
0
0
2
0
0
1
4
0
1
0
8
0
1
1
16
1
0
0
32
1
0
1
64
1
1
0
128
1
1
1
Bits 2:0 = SCR[2:0] SCI Receiver rate divisor.
These 3 bits, in conjunction with the SCP[1:0] bits
define the total division applied to the bus clock to
yield the receive rate clock.
BAUD RATE REGISTER (SCIBRR)
Read/Write
Reset Value: 0000 0000 (00h)
SCP1
TR dividing factor
SCP0
1
0
0
3
0
1
RR Dividing factor
SCR2
SCR1
SCR0
1
0
0
0
2
0
0
1
4
0
1
0
8
0
1
1
16
1
0
0
32
1
0
1
64
1
1
0
128
1
1
1
ST7260
Table 20. SCI Register Map and Reset Values
Address
(Hex.)
Register
Label
7
6
5
4
3
2
1
0
20
SCISR
Reset Value
TDRE
1
TC
1
RDRF
0
IDLE
0
OR
0
NF
0
FE
0
PE
0
21
SCIDR
Reset Value
DR7
x
DR6
x
DR5
x
DR4
x
DR3
x
DR2
x
DR1
x
DR0
x
22
SCIBRR
Reset Value
SCP1
0
SCP0
0
SCT2
x
SCT1
x
SCT0
x
SCR2
x
SCR1
x
SCR0
x
23
SCICR1
Reset Value
R8
x
T8
x
SCID
0
M
x
WAKE
x
PCE
0
PS
0
PIE
0
24
SCICR2
Reset Value
TIE
0
TCIE
0
RIE
0
ILIE
0
TE
0
RE
0
RWU
0
SBK
0
71/117
ST7260
11.4 USB INTERFACE (USB)
11.4.1 Introduction
The USB Interface implements a low-speed function interface between the USB and the ST7 microcontroller. It is a highly integrated circuit which
includes the transceiver, 3.3 voltage regulator, SIE
and DMA. No external components are needed
apart from the external pull-up on USBDM for low
speed recognition by the USB host. The use of
DMA architecture allows the endpoint definition to
be completely flexible. Endpoints can be configured by software as in or out.
11.4.2 Main Features
■ USB Specification Version 1.1 Compliant
■ Supports Low-Speed USB Protocol
■ Two or Three Endpoints (including default one)
depending on the device (see device feature list
and register map)
■ CRC
generation/checking, NRZI encoding/
decoding and bit-stuffing
■ USB Suspend/Resume operations
■ DMA Data transfers
■ On-Chip 3.3V Regulator
■ On-Chip USB Transceiver
11.4.3 Functional Description
The block diagram in Figure 38, gives an overview
of the USB interface hardware.
For general information on the USB, refer to the
“Universal Serial Bus Specifications” document
available at http//:www.usb.org.
Serial Interface Engine
The SIE (Serial Interface Engine) interfaces with
the USB, via the transceiver.
The SIE processes tokens, handles data transmission/reception, and handshaking as required by
the USB standard. It also performs frame formatting, including CRC generation and checking.
Endpoints
The Endpoint registers indicate if the microcontroller is ready to transmit/receive, and how many
bytes need to be transmitted.
DMA
When a token for a valid Endpoint is recognized by
the USB interface, the related data transfer takes
place, using DMA. At the end of the transaction, an
interrupt is generated.
Interrupts
By reading the Interrupt Status register, application software can know which USB event has occurred.
Figure 38. USB Block Diagram
6 MHz
ENDPOINT
REGISTERS
USBDM
Transceiver
USBDP
SIE
DMA
CPU
Address,
data buses
and interrupts
USBVCC
USBGND
72/117
3.3V
Voltage
Regulator
INTERRUPT
REGISTERS
MEMORY
ST7260
USB INTERFACE (Cont’d)
11.4.4 Register Description
DMA ADDRESS REGISTER (DMAR)
Read / Write
Reset Value: Undefined
INTERRUPT/DMA REGISTER (IDR)
Read / Write
Reset Value: xxxx 0000 (x0h)
7
7
DA15
0
DA14
DA13
DA12
DA11
DA10
DA9
DA7
0
DA6
EP1
EP0
CNT3
CNT2
CNT1
CNT0
DA8
Bits 7:0=DA[15:8] DMA address bits 15-8.
Software must write the start address of the DMA
memory area whose most significant bits are given
by DA15-DA6. The remaining 6 address bits are
set by hardware. See the description of the IDR
register and Figure 39.
Bits 7:6 = DA[7:6] DMA address bits 7-6.
Software must reset these bits. See the description of the DMAR register and Figure 39.
Bits 5:4 = EP[1:0] Endpoint number (read-only).
These bits identify the endpoint which required attention.
00: Endpoint 0
01: Endpoint 1
10: Endpoint 2
When a CTR interrupt occurs (see register ISTR)
the software should read the EP bits to identify the
endpoint which has sent or received a packet.
Bits 3:0 = CNT[3:0] Byte count (read only).
This field shows how many data bytes have been
received during the last data reception.
Note: Not valid for data transmission.
Figure 39. DMA Buffers
101111
Endpoint 2 TX
101000
100111
Endpoint 2 RX
100000
011111
011000
010111
010000
001111
Endpoint 1 TX
Endpoint 1 RX
Endpoint 0 TX
001000
000111
Endpoint 0 RX
DA15-6,000000
000000
73/117
ST7260
USB INTERFACE (Cont’d)
PID REGISTER (PIDR)
Read only
Reset Value: xx00 0000 (x0h)
INTERRUPT STATUS REGISTER (ISTR)
Read / Write
Reset Value: 0000 0000 (00h)
7
0
TP3
TP2
0
0
0
RX_
SEZ
RXD
0
Bits 7:6 = TP[3:2] Token PID bits 3 & 2.
USB token PIDs are encoded in four bits. TP[3:2]
correspond to the variable token PID bits 3 & 2.
Note: PID bits 1 & 0 have a fixed value of 01.
When a CTR interrupt occurs (see register ISTR)
the software should read the TP3 and TP2 bits to
retrieve the PID name of the token received.
The USB standard defines TP bits as:
TP3
0
1
1
TP2
0
0
1
PID Name
OUT
IN
SETUP
7
SUSP
0
DOVR
CTR
ERR
IOVR
ESUSP
RESET
SOF
When an interrupt occurs these bits are set by
hardware. Software must read them to determine
the interrupt type and clear them after servicing.
Note: These bits cannot be set by software.
Bit 7 = SUSP Suspend mode request.
This bit is set by hardware when a constant idle
state is present on the bus line for more than 3 ms,
indicating a suspend mode request from the USB
bus. The suspend request check is active immediately after each USB reset event and its disabled
by hardware when suspend mode is forced
(FSUSP bit of CTLR register) until the end of
resume sequence.
Bits 5:3 Reserved. Forced by hardware to 0.
Bit 2 = RX_SEZ Received single-ended zero
This bit indicates the status of the RX_SEZ transceiver output.
0: No SE0 (single-ended zero) state
1: USB lines are in SE0 (single-ended zero) state
Bit 1 = RXD Received data
0: No K-state
1: USB lines are in K-state
This bit indicates the status of the RXD transceiver
output (differential receiver output).
Note: If the environment is noisy, the RX_SEZ and
RXD bits can be used to secure the application. By
interpreting the status, software can distinguish a
valid End Suspend event from a spurious wake-up
due to noise on the external USB line. A valid End
Suspend is followed by a Resume or Reset sequence. A Resume is indicated by RXD=1, a Reset is indicated by RX_SEZ=1.
Bit 0 = Reserved. Forced by hardware to 0.
74/117
Bit 6 = DOVR DMA over/underrun.
This bit is set by hardware if the ST7 processor
can’t answer a DMA request in time.
0: No over/underrun detected
1: Over/underrun detected
Bit 5 = CTR Correct Transfer. This bit is set by
hardware when a correct transfer operation is performed. The type of transfer can be determined by
looking at bits TP3-TP2 in register PIDR. The Endpoint on which the transfer was made is identified
by bits EP1-EP0 in register IDR.
0: No Correct Transfer detected
1: Correct Transfer detected
Note: A transfer where the device sent a NAK or
STALL handshake is considered not correct (the
host only sends ACK handshakes). A transfer is
considered correct if there are no errors in the PID
and CRC fields, if the DATA0/DATA1 PID is sent
as expected, if there were no data overruns, bit
stuffing or framing errors.
Bit 4 = ERR Error.
This bit is set by hardware whenever one of the errors listed below has occurred:
0: No error detected
1: Timeout, CRC, bit stuffing or nonstandard
framing error detected
ST7260
USB INTERFACE (Cont’d)
Bit 3 = IOVR Interrupt overrun.
This bit is set when hardware tries to set ERR, or
SOF before they have been cleared by software.
0: No overrun detected
1: Overrun detected
Bit 2 = ESUSP End suspend mode.
This bit is set by hardware when, during suspend
mode, activity is detected that wakes the USB interface up from suspend mode.
This interrupt is serviced by a specific vector, in order to wake up the ST7 from HALT mode.
0: No End Suspend detected
1: End Suspend detected
Bit 1 = RESET USB reset.
This bit is set by hardware when the USB reset sequence is detected on the bus.
0: No USB reset signal detected
1: USB reset signal detected
Note: The DADDR, EP0RA, EP0RB, EP1RA,
EP1RB, EP2RA and EP2RB registers are reset by
a USB reset.
Bit 0 = SOF Start of frame.
This bit is set by hardware when a low-speed SOF
indication (keep-alive strobe) is seen on the USB
bus. It is also issued at the end of a resume sequence.
0: No SOF signal detected
1: SOF signal detected
Note: To avoid spurious clearing of some bits, it is
recommended to clear them using a load instruction where all bits which must not be altered are
set, and all bits to be cleared are reset. Avoid readmodify-write instructions like AND , XOR..
INTERRUPT MASK REGISTER (IMR)
Read / Write
Reset Value: 0000 0000 (00h)
7
SUS
PM
0
DOV
RM
CTR
M
ERR
M
IOVR
M
ESU
SPM
RES
ETM
SOF
M
Bits 7:0 = These bits are mask bits for all interrupt
condition bits included in the ISTR. Whenever one
of the IMR bits is set, if the corresponding ISTR bit
is set, and the I bit in the CC register is cleared, an
interrupt request is generated. For an explanation
of each bit, please refer to the corresponding bit
description in ISTR.
CONTROL REGISTER (CTLR)
Read / Write
Reset Value: 0000 0110 (06h)
7
0
0
0
0
0
RESUME
PDWN
FSUSP
FRES
Bits 7:4 = Reserved. Forced by hardware to 0.
Bit 3 = RESUME Resume.
This bit is set by software to wake-up the Host
when the ST7 is in suspend mode.
0: Resume signal not forced
1: Resume signal forced on the USB bus.
Software should clear this bit after the appropriate
delay.
Bit 2 = PDWN Power down.
This bit is set by software to turn off the 3.3V onchip voltage regulator that supplies the external
pull-up resistor and the transceiver.
0: Voltage regulator on
1: Voltage regulator off
Note: After turning on the voltage regulator, software should allow at least 3 µs for stabilisation of
the power supply before using the USB interface.
Bit 1 = FSUSP Force suspend mode.
This bit is set by software to enter Suspend mode.
The ST7 should also be halted allowing at least
600 ns before issuing the HALT instruction.
0: Suspend mode inactive
1: Suspend mode active
When the hardware detects USB activity, it resets
this bit (it can also be reset by software).
Bit 0 = FRES Force reset.
This bit is set by software to force a reset of the
USB interface, just as if a RESET sequence came
from the USB.
0: Reset not forced
1: USB interface reset forced.
The USB is held in RESET state until software
clears this bit, at which point a “USB-RESET” interrupt will be generated if enabled.
75/117
ST7260
USB INTERFACE (Cont’d)
DEVICE ADDRESS REGISTER (DADDR)
Read / Write
Reset Value: 0000 0000 (00h)
7
0
0
ADD6
ADD5
ADD4
ADD3
ADD2
ADD1
ADD0
Bit 7 = Reserved. Forced by hardware to 0.
Bits 6:0 = ADD[6:0] Device address, 7 bits.
Software must write into this register the address
sent by the host during enumeration.
Note: This register is also reset when a USB reset
is received from the USB bus or forced through bit
FRES in the CTLR register.
ENDPOINT n REGISTER A (EPnRA)
Read / Write
Reset Value: 0000 xxxx (0xh)
7
ST_
OUT
0
DTOG
_TX
STAT
_TX1
STAT
_TX0
TBC
3
TBC
2
TBC
1
TBC
0
These registers (EP0RA, EP1RA and EP2RA) are
used for controlling data transmission. They are
also reset by the USB bus reset.
Note: Endpoint 2 and the EP2RA register are not
available on some devices (see device feature list
and register map).
Bit 7 = ST_OUT Status out.
This bit is set by software to indicate that a status
out packet is expected: in this case, all nonzero
OUT data transfers on the endpoint are STALLed
instead of being ACKed. When ST_OUT is reset,
OUT transactions can have any number of bytes,
as needed.
76/117
Bit 6 = DTOG_TX Data Toggle, for transmission
transfers.
It contains the required value of the toggle bit
(0=DATA0, 1=DATA1) for the next transmitted
data packet. This bit is set by hardware at the reception of a SETUP PID. DTOG_TX toggles only
when the transmitter has received the ACK signal
from the USB host. DTOG_TX and also
DTOG_RX (see EPnRB) are normally updated by
hardware, at the receipt of a relevant PID. They
can be also written by software.
Bits 5:4 = STAT_TX[1:0] Status bits, for transmission transfers.
These bits contain the information about the endpoint status, which are listed below:
STAT_TX1 STAT_TX0 Meaning
DISABLED: transmission
0
0
transfers cannot be executed.
STALL: the endpoint is stalled
0
1
and all transmission requests
result in a STALL handshake.
NAK: the endpoint is naked
1
0
and all transmission requests
result in a NAK handshake.
VALID: this endpoint is ena1
1
bled for transmission.
These bits are written by software. Hardware sets
the STAT_TX bits to NAK when a correct transfer
has occurred (CTR=1) related to a IN or SETUP
transaction addressed to this endpoint; this allows
the software to prepare the next set of data to be
transmitted.
Bits 3:0 = TBC[3:0] Transmit byte count for Endpoint n.
Before transmission, after filling the transmit buffer, software must write in the TBC field the transmit packet size expressed in bytes (in the range 08).
Warning: Any value outside the range 0-8 willinduce undesired effects (such as continuous data
transmission).
ST7260
USB INTERFACE (Cont’d)
ENDPOINT n REGISTER B (EPnRB)
Read / Write
Reset Value: 0000 xxxx (0xh)
STAT_RX1
7
CTRL
STAT_RX0 Meaning
1
0
1
1
NAK: the endpoint is naked and all reception requests result in a NAK
handshake.
VALID: this endpoint is
enabled for reception.
0
DTOG
_RX
STAT
_RX1
STAT
_RX0
EA3
EA2
EA1
EA0
These registers (EP1RB and EP2RB) are used for
controlling data reception on Endpoints 1 and 2.
They are also reset by the USB bus reset.
Note: Endpoint 2 and the EP2RB register are not
available on some devices (see device feature list
and register map).
Bit 7 = CTRL Control.
This bit should be 0.
Note: If this bit is 1, the Endpoint is a control endpoint. (Endpoint 0 is always a control Endpoint, but
it is possible to have more than one control Endpoint).
Bit 6 = DTOG_RX Data toggle, for reception transfers.
It contains the expected value of the toggle bit
(0=DATA0, 1=DATA1) for the next data packet.
This bit is cleared by hardware in the first stage
(Setup Stage) of a control transfer (SETUP transactions start always with DATA0 PID). The receiver toggles DTOG_RX only if it receives a correct
data packet and the packet’s data PID matches
the receiver sequence bit.
Bits 5:4 = STAT_RX [1:0] Status bits, for reception
transfers.
These bits contain the information about the endpoint status, which are listed below:
STAT_RX1
STAT_RX0 Meaning
0
0
0
1
DISABLED: reception
transfers cannot be executed.
STALL: the endpoint is
stalled and all reception
requests result in a
STALL handshake.
These bits are written by software. Hardware sets
the STAT_RX bits to NAK when a correct transfer
has occurred (CTR=1) related to an OUT or SETUP transaction addressed to this endpoint, so the
software has the time to elaborate the received
data before acknowledging a new transaction.
Bits 3:0 = EA[3:0] Endpoint address.
Software must write in this field the 4-bit address
used to identify the transactions directed to this
endpoint. Usually EP1RB contains “0001” and
EP2RB contains “0010”.
ENDPOINT 0 REGISTER B (EP0RB)
Read / Write
Reset Value: 1000 0000 (80h)
7
1
0
DTOG
RX
STAT
RX1
STAT
RX0
0
0
0
0
This register is used for controlling data reception
on Endpoint 0. It is also reset by the USB bus reset.
Bit 7 = Forced by hardware to 1.
Bits 6:4 = Refer to the EPnRB register for a description of these bits.
Bits 3:0 = Forced by hardware to 0.
77/117
ST7260
USB INTERFACE (Cont’d)
11.4.5 Programming Considerations
The interaction between the USB interface and the
application program is described below. Apart
from system reset, action is always initiated by the
USB interface, driven by one of the USB events
associated with the Interrupt Status Register (ISTR) bits.
11.4.5.1 Initializing the Registers
At system reset, the software must initialize all registers to enable the USB interface to properly generate interrupts and DMA requests.
1. Initialize the DMAR, IDR, and IMR registers
(choice of enabled interrupts, address of DMA
buffers). Refer the paragraph titled initializing
the DMA Buffers.
2. Initialize the EP0RA and EP0RB registers to
enable accesses to address 0 and endpoint 0
to support USB enumeration. Refer to the paragraph titled Endpoint Initialization.
3. When addresses are received through this
channel, update the content of the DADDR.
4. If needed, write the endpoint numbers in the EA
fields in the EP1RB and EP2RB register.
11.4.5.2 Initializing DMA buffers
The DMA buffers are a contiguous zone of memory whose maximum size is 48 bytes. They can be
placed anywhere in the memory space to enable
the reception of messages. The 10 most significant bits of the start of this memory area are specified by bits DA15-DA6 in registers DMAR and
IDR, the remaining bits are 0. The memory map is
shown in Figure 39.
Each buffer is filled starting from the bottom (last 3
address bits=000) up.
11.4.5.3 Endpoint Initialization
To be ready to receive:
Set STAT_RX to VALID (11b) in EP0RB to enable
reception.
To be ready to transmit:
1. Write the data in the DMA transmit buffer.
2. In register EPnRA, specify the number of bytes
to be transmitted in the TBC field
3. Enable the endpoint by setting the STAT_TX
bits to VALID (11b) in EPnRA.
Note: Once transmission and/or reception are enabled, registers EPnRA and/or EPnRB (respec-
78/117
tively) must not be modified by software, as the
hardware can change their value on the fly.
When the operation is completed, they can be accessed again to enable a new operation.
11.4.5.4 Interrupt Handling
Start of Frame (SOF)
The interrupt service routine may monitor the SOF
events for a 1 ms synchronization event to the
USB bus. This interrupt is generated at the end of
a resume sequence and can also be used to detect this event.
USB Reset (RESET)
When this event occurs, the DADDR register is reset, and communication is disabled in all endpoint
registers (the USB interface will not respond to any
packet). Software is responsible for reenabling
endpoint 0 within 10 ms of the end of reset. To do
this, set the STAT_RX bits in the EP0RB register
to VALID.
Suspend (SUSP)
The CPU is warned about the lack of bus activity
for more than 3 ms, which is a suspend request.
The software should set the USB interface to suspend mode and execute an ST7 HALT instruction
to meet the USB-specified power constraints.
End Suspend (ESUSP)
The CPU is alerted by activity on the USB, which
causes an ESUSP interrupt. The ST7 automatically terminates HALT mode.
Correct Transfer (CTR)
1. When this event occurs, the hardware automatically sets the STAT_TX or STAT_RX to NAK.
Note: Every valid endpoint is NAKed until software clears the CTR bit in the ISTR register,
independently of the endpoint number
addressed by the transfer which generated the
CTR interrupt.
Note: If the event triggering the CTR interrupt is
a SETUP transaction, both STAT_TX and
STAT_RX are set to NAK.
2. Read the PIDR to obtain the token and the IDR
to get the endpoint number related to the last
transfer.
Note: When a CTR interrupt occurs, the TP3TP2 bits in the PIDR register and EP1-EP0 bits
in the IDR register stay unchanged until the
CTR bit in the ISTR register is cleared.
3. Clear the CTR bit in the ISTR register.
ST7260
USB INTERFACE (Cont’d)
Table 21. USB Register Map and Reset Values
Address
(Hex.)
25
26
27
28
29
2A
2B
2C
2D
2E
2F
30
31
Register
Name
7
6
5
4
3
2
1
0
TP3
TP2
0
0
0
RX_SEZ
RXD
0
Reset Value
DMAR
x
DA15
x
DA14
0
DA13
0
DA12
0
DA11
0
DA10
0
DA9
0
DA8
Reset Value
IDR
x
DA7
x
DA6
x
EP1
x
EP0
x
CNT3
x
CNT2
x
CNT1
x
CNT0
Reset Value
ISTR
x
SUSP
x
DOVR
x
CTR
x
ERR
0
IOVR
0
ESUSP
0
RESET
0
SOF
Reset Value
IMR
0
SUSPM
0
DOVRM
0
CTRM
0
ERRM
0
IOVRM
Reset Value
CTLR
0
0
0
0
0
0
0
0
0
RESUME
0
PDWN
0
FSUSP
0
FRES
Reset Value
DADDR
0
0
0
ADD6
0
ADD5
0
ADD4
0
ADD3
1
ADD2
1
ADD1
0
ADD0
0
TBC3
0
TBC2
0
TBC1
0
TBC0
Reset Value
EP0RB
0
0
0
0
ST_OUT DTOG_TX STAT_TX1 STAT_TX0
0
0
0
0
1
DTOG_RX STAT_RX1 STAT_RX0
x
0
x
0
x
0
x
0
Reset Value
EP1RA
1
0
0
0
ST_OUT DTOG_TX STAT_TX1 STAT_TX0
0
TBC3
0
TBC2
0
TBC1
0
TBC0
x
EA3
x
EA2
x
EA1
x
EA0
x
TBC3
x
TBC2
x
TBC1
x
TBC0
x
EA3
x
EA2
x
EA1
x
EA0
x
x
x
x
PIDR
Reset Value
EP0RA
Reset Value
EP1RB
Reset Value
EP2RA
0
CTRL
0
0
0
DTOG_RX STAT_RX1 STAT_RX0
0
0
0
0
ST_OUT DTOG_TX STAT_TX1 STAT_TX0
Reset Value
EP2RB
0
CTRL
Reset Value
0
0
0
0
DTOG_RX STAT_RX1 STAT_RX0
0
0
0
0
0
ESUSPM RESETM
0
SOFM
79/117
ST7260
12 INSTRUCTION SET
12.1 ST7 ADDRESSING MODES
The ST7 Core features 17 different addressing
modes which can be classified in 7 main groups:
Addressing Mode
Example
Inherent
nop
Immediate
ld A,#$55
Direct
ld A,$55
Indexed
ld A,($55,X)
Indirect
ld A,([$55],X)
Relative
jrne loop
Bit operation
bset
byte,#5
The ST7 Instruction set is designed to minimize
the number of bytes required per instruction: To do
so, most of the addressing modes may be subdivided in two sub-modes called long and short:
– Long addressing mode is more powerful because it can use the full 64 Kbyte address space,
however it uses more bytes and more CPU cycles.
– Short addressing mode is less powerful because
it can generally only access page zero (0000h 00FFh range), but the instruction size is more
compact, and faster. All memory to memory instructions use short addressing modes only
(CLR, CPL, NEG, BSET, BRES, BTJT, BTJF,
INC, DEC, RLC, RRC, SLL, SRL, SRA, SWAP)
The ST7 Assembler optimizes the use of long and
short addressing modes.
Table 22. ST7 Addressing Mode Overview
Mode
Syntax
Pointer
Address
(Hex.)
Destination/
Source
Pointer
Size
(Hex.)
Length
(Bytes)
Inherent
nop
+0
Immediate
ld A,#$55
+1
Short
Direct
ld A,$10
00..FF
+1
Long
Direct
ld A,$1000
0000..FFFF
+2
No Offset
Direct
Indexed
ld A,(X)
00..FF
+ 0 (with X register)
+ 1 (with Y register)
Short
Direct
Indexed
ld A,($10,X)
00..1FE
+1
Long
Direct
Indexed
Short
Indirect
ld A,($1000,X)
0000..FFFF
ld A,[$10]
00..FF
00..FF
byte
+2
+2
Long
Indirect
ld A,[$10.w]
0000..FFFF
00..FF
word
+2
Short
Indirect
Indexed
ld A,([$10],X)
00..1FE
00..FF
byte
+2
Long
Indirect
Indexed
ld A,([$10.w],X)
0000..FFFF
00..FF
word
+2
00..FF
byte
+2
00..FF
byte
+2
1)
Relative
Direct
jrne loop
PC-128/PC+127
Relative
Indirect
jrne [$10]
PC-128/PC+1271)
Bit
Direct
bset $10,#7
00..FF
Bit
Indirect
bset [$10],#7
00..FF
Bit
Direct
Relative
btjt $10,#7,skip
00..FF
Bit
Indirect
Relative
btjt [$10],#7,skip 00..FF
+1
+1
+2
00..FF
byte
+3
Note 1. At the time the instruction is executed, the Program Counter (PC) points to the instruction following JRxx.
80/117
ST7260
ST7 ADDRESSING MODES (Cont’d)
12.1.1 Inherent
All Inherent instructions consist of a single byte.
The opcode fully specifies all the required information for the CPU to process the operation.
Inherent Instruction
Function
NOP
No operation
TRAP
S/W Interrupt
WFI
Wait For Interrupt (Low Power
Mode)
HALT
Halt Oscillator (Lowest Power
Mode)
RET
Sub-routine Return
IRET
Interrupt Sub-routine Return
SIM
Set Interrupt Mask
RIM
Reset Interrupt Mask
SCF
Set Carry Flag
RCF
Reset Carry Flag
RSP
Reset Stack Pointer
LD
Load
CLR
Clear
PUSH/POP
Push/Pop to/from the stack
INC/DEC
Increment/Decrement
TNZ
Test Negative or Zero
CPL, NEG
1 or 2 Complement
MUL
Byte Multiplication
SLL, SRL, SRA, RLC,
RRC
Shift and Rotate Operations
SWAP
Swap Nibbles
12.1.2 Immediate
Immediate instructions have two bytes, the first
byte contains the opcode, the second byte contains the operand value.
Immediate Instruction
Function
LD
Load
CP
Compare
BCP
Bit Compare
AND, OR, XOR
Logical Operations
ADC, ADD, SUB, SBC
Arithmetic Operations
12.1.3 Direct
In Direct instructions, the operands are referenced
by their memory address.
The direct addressing mode consists of two submodes:
Direct (short)
The address is a byte, thus requires only one byte
after the opcode, but only allows 00 - FF addressing space.
Direct (long)
The address is a word, thus allowing 64 Kbyte addressing space, but requires 2 bytes after the opcode.
12.1.4 Indexed (No Offset, Short, Long)
In this mode, the operand is referenced by its
memory address, which is defined by the unsigned
addition of an index register (X or Y) with an offset.
The indirect addressing mode consists of three
sub-modes:
Indexed (No Offset)
There is no offset, (no extra byte after the opcode),
and allows 00 - FF addressing space.
Indexed (Short)
The offset is a byte, thus requires only one byte after the opcode and allows 00 - 1FE addressing
space.
Indexed (long)
The offset is a word, thus allowing 64 Kbyte addressing space and requires 2 bytes after the opcode.
12.1.5 Indirect (Short, Long)
The required data byte to do the operation is found
by its memory address, located in memory (pointer).
The pointer address follows the opcode. The indirect addressing mode consists of two sub-modes:
Indirect (short)
The pointer address is a byte, the pointer size is a
byte, thus allowing 00 - FF addressing space, and
requires 1 byte after the opcode.
Indirect (long)
The pointer address is a byte, the pointer size is a
word, thus allowing 64 Kbyte addressing space,
and requires 1 byte after the opcode.
81/117
ST7260
ST7 ADDRESSING MODES (Cont’d)
12.1.6 Indirect Indexed (Short, Long)
This is a combination of indirect and short indexed
addressing modes. The operand is referenced by
its memory address, which is defined by the unsigned addition of an index register value (X or Y)
with a pointer value located in memory. The pointer address follows the opcode.
The indirect indexed addressing mode consists of
two sub-modes:
Indirect Indexed (Short)
The pointer address is a byte, the pointer size is a
byte, thus allowing 00 - 1FE addressing space,
and requires 1 byte after the opcode.
Indirect Indexed (Long)
The pointer address is a byte, the pointer size is a
word, thus allowing 64 Kbyte addressing space,
and requires 1 byte after the opcode.
Table 23. Instructions Supporting Direct,
Indexed, Indirect and Indirect Indexed
Addressing Modes
Long and Short
Instructions
Function
LD
Load
CP
Compare
AND, OR, XOR
Logical Operations
ADC, ADD, SUB, SBC
Arithmetic Addition/subtraction operations
BCP
Bit Compare
Short Instructions Only
Function
CLR
Clear
INC, DEC
Increment/Decrement
TNZ
Test Negative or Zero
CPL, NEG
1 or 2 Complement
BSET, BRES
Bit Operations
BTJT, BTJF
Bit Test and Jump Operations
SLL, SRL, SRA, RLC,
RRC
Shift and Rotate Operations
82/117
SWAP
Swap Nibbles
CALL, JP
Call or Jump subroutine
12.1.7 Relative Mode (Direct, Indirect)
This addressing mode is used to modify the PC
register value by adding an 8-bit signed offset to it.
Available Relative Direct/
Indirect Instructions
Function
JRxx
Conditional Jump
CALLR
Call Relative
The relative addressing mode consists of two submodes:
Relative (Direct)
The offset follows the opcode.
Relative (Indirect)
The offset is defined in memory, of which the address follows the opcode.
ST7260
12.2 INSTRUCTION GROUPS
The ST7 family devices use an Instruction Set
consisting of 63 instructions. The instructions may
be subdivided into 13 main groups as illustrated in
the following table:
Load and Transfer
LD
CLR
Stack operation
PUSH
POP
Increment/Decrement
INC
DEC
Compare and Tests
CP
TNZ
BCP
Logical operations
AND
OR
XOR
CPL
NEG
Bit Operation
BSET
BRES
Conditional Bit Test and Branch
BTJT
BTJF
Arithmetic operations
ADC
ADD
SUB
SBC
MUL
Shift and Rotates
SLL
SRL
SRA
RLC
RRC
SWAP
SLA
Unconditional Jump or Call
JRA
JRT
JRF
JP
CALL
CALLR
NOP
Conditional Branch
JRxx
Interruption management
TRAP
WFI
HALT
IRET
Condition Code Flag modification
SIM
RIM
SCF
RCF
Using a pre-byte
The instructions are described with one to four
bytes.
In order to extend the number of available opcodes for an 8-bit CPU (256 opcodes), three different prebyte opcodes are defined. These prebytes
modify the meaning of the instruction they precede.
The whole instruction becomes:
PC-2 End of previous instruction
PC-1 Prebyte
PC
Opcode
PC+1 Additional word (0 to 2) according to the
number of bytes required to compute the
effective address
RSP
RET
These prebytes enable instruction in Y as well as
indirect addressing modes to be implemented.
They precede the opcode of the instruction in X or
the instruction using direct addressing mode. The
prebytes are:
PDY 90 Replace an X based instruction using
immediate, direct, indexed, or inherent
addressing mode by a Y one.
PIX 92 Replace an instruction using direct, direct bit, or direct relative addressing
mode to an instruction using the corresponding indirect addressing mode.
It also changes an instruction using X
indexed addressing mode to an instruction using indirect X indexed addressing
mode.
PIY 91 Replace an instruction using X indirect
indexed addressing mode by a Y one.
83/117
ST7260
INSTRUCTION GROUPS (Cont’d)
Mnemo
Description
Function/Example
Dst
Src
H
I
N
Z
C
ADC
Add with Carry
A=A+M+C
A
M
H
N
Z
C
ADD
Addition
A=A+M
A
M
H
N
Z
C
AND
Logical And
A=A.M
A
M
N
Z
BCP
Bit compare A, Memory
tst (A . M)
A
M
N
Z
BRES
Bit Reset
bres Byte, #3
M
BSET
Bit Set
bset Byte, #3
M
BTJF
Jump if bit is false (0)
btjf Byte, #3, Jmp1
M
C
BTJT
Jump if bit is true (1)
btjt Byte, #3, Jmp1
M
C
CALL
Call subroutine
CALLR
Call subroutine relative
CLR
Clear
CP
Arithmetic Compare
tst(Reg - M)
reg
CPL
One Complement
A = FFH-A
DEC
Decrement
dec Y
reg, M
HALT
Halt
IRET
Interrupt routine return
Pop CC, A, X, PC
INC
Increment
inc X
JP
Absolute Jump
jp [TBL.w]
JRA
Jump relative always
JRT
Jump relative
JRF
Never jump
JRIH
Jump if ext. interrupt = 1
1
Z
C
reg, M
N
Z
1
reg, M
N
Z
N
Z
N
Z
0
jrf *
JRIL
Jump if ext. interrupt = 0
JRH
Jump if H = 1
H=1?
JRNH
Jump if H = 0
H=0?
JRM
Jump if I = 1
I=1?
JRNM
Jump if I = 0
I=0?
JRMI
Jump if N = 1 (minus)
N=1?
JRPL
Jump if N = 0 (plus)
N=0?
JREQ
Jump if Z = 1 (equal)
Z=1?
JRNE
Jump if Z = 0 (not equal)
Z=0?
JRC
Jump if C = 1
C=1?
JRNC
Jump if C = 0
C=0?
JRULT
Jump if C = 1
Unsigned <
JRUGE
Jump if C = 0
Jmp if unsigned >=
JRUGT
Jump if (C + Z = 0)
Unsigned >
84/117
0
N
M
H
reg, M
I
C
ST7260
INSTRUCTION GROUPS (Cont’d)
Mnemo
Description
Function/Example
Dst
Src
JRULE
Jump if (C + Z = 1)
Unsigned <=
LD
Load
dst <= src
reg, M
M, reg
MUL
Multiply
X,A = X * A
A, X, Y
X, Y, A
NEG
Negate (2's compl)
neg $10
reg, M
NOP
No Operation
OR
OR operation
A=A+M
A
M
POP
Pop from the Stack
pop reg
reg
M
pop CC
CC
M
M
reg, CC
H
I
N
Z
N
Z
0
H
C
0
I
N
Z
N
Z
N
Z
C
C
PUSH
Push onto the Stack
push Y
RCF
Reset carry flag
C=0
RET
Subroutine Return
RIM
Enable Interrupts
I=0
RLC
Rotate left true C
C <= Dst <= C
reg, M
N
Z
C
RRC
Rotate right true C
C => Dst => C
reg, M
N
Z
C
RSP
Reset Stack Pointer
S = Max allowed
SBC
Subtract with Carry
A=A-M-C
N
Z
C
SCF
Set carry flag
C=1
SIM
Disable Interrupts
I=1
SLA
Shift left Arithmetic
C <= Dst <= 0
reg, M
N
Z
C
SLL
Shift left Logic
C <= Dst <= 0
reg, M
N
Z
C
SRL
Shift right Logic
0 => Dst => C
reg, M
0
Z
C
SRA
Shift right Arithmetic
Dst7 => Dst => C
reg, M
N
Z
C
SUB
Subtraction
A=A-M
A
N
Z
C
SWAP
SWAP nibbles
Dst[7..4] <=> Dst[3..0] reg, M
N
Z
TNZ
Test for Neg & Zero
tnz lbl1
N
Z
TRAP
S/W trap
S/W interrupt
WFI
Wait for Interrupt
XOR
Exclusive OR
N
Z
0
0
A
M
1
1
M
1
0
A = A XOR M
A
M
85/117
ST7260
13 ELECTRICAL CHARACTERISTICS
13.1 PARAMETER CONDITIONS
Unless otherwise specified, all voltages are referred to VSS.
13.1.1 Minimum and Maximum values
Unless otherwise specified the minimum and maximum values are guaranteed in the worst conditions of ambient temperature, supply voltage and
frequencies by tests in production on 100% of the
devices with an ambient temperature at TA=25°C
and TA=TAmax (given by the selected temperature
range).
Data based on characterization results, design
simulation and/or technology characteristics are
indicated in the table footnotes and are not tested
in production. Based on characterization, the minimum and maximum values refer to sample tests
and represent the mean value plus or minus three
times the standard deviation (mean±3Σ).
13.1.2 Typical values
Unless otherwise specified, typical data are based
on TA=25°C, VDD=5V. They are given only as design guidelines and are not tested.
13.1.3 Typical curves
Unless otherwise specified, all typical curves are
given only as design guidelines and are not tested.
13.1.4 Loading capacitor
The loading conditions used for pin parameter
measurement are shown in Figure 40.
Figure 40. Pin loading conditions
ST7 PIN
CL
13.1.5 Pin input voltage
The input voltage measurement on a pin of the device is described in Figure 41.
86/117
Figure 41. Pin input voltage
ST7 PIN
VIN
ST7260
13.2 ABSOLUTE MAXIMUM RATINGS
Stresses above those listed as “absolute maximum ratings” may cause permanent damage to
the device. This is a stress rating only and functional operation of the device under these condi13.2.1 Voltage Characteristics
Symbol
VDD - VSS
VIN1) & 2)
VESD(HBM)
tions is not implied. Exposure to maximum rating
conditions for extended periods may affect device
reliability.
Ratings
Maximum value
Supply voltage
Unit
6.0
Input voltage on true open drain pins
VSS-0.3 to 6.0
V
VSS-0.3 to VDD+0.3
Input voltage on any other pin
Electro-static discharge voltage (Human Body Model)
See “Absolute Maximum Ratings
(Electrical Sensitivity)” on page 94.
13.2.2 Current Characteristics
Symbol
Ratings
Maximum value
IVDD
Total current into VDD power lines (source)
3)
80
IVSS
Total current out of VSS ground lines (sink) 3)
80
IIO
IINJ(PIN) 2)
ΣIINJ(PIN) 2)
IINJ(PIN)
2)
Output current sunk by any standard I/O and control pin
25
Output current sunk by any high sink I/O pin
50
Output current source by any I/Os and control pin
- 25
Injected current on VPP pin
±5
Injected current on RESET pin
±5
Injected current on OSCIN and OSCOUT pins
±5
Injected current on any other pin 4) & 5)
±5
Total injected current (sum of all I/O and control pins) 4)
± 20
Negative injected current to PB0(10mA)/AIN0 pin
- 80
Unit
mA
µA
Notes:
1. Directly connecting the RESET and I/O pins to VDD or VSS could damage the device if an unintentional internal reset
is generated or an unexpected change of the I/O configuration occurs (for example, due to a corrupted program counter).
To guarantee safe operation, this connection has to be done through a pull-up or pull-down resistor (typical: 4.7kΩ for
RESET, 10kΩ for I/Os). Unused I/O pins must be tied in the same way to VDD or VSS according to their reset configuration.
2. IINJ(PIN) must never be exceeded. This is implicitly insured if VIN maximum is respected. If VIN maximum cannot be
respected, the injection current must be limited externally to the IINJ(PIN) value. A positive injection is induced by VIN>VDD
while a negative injection is induced by VIN<VSS. For true open-drain pads, there is no positive injection current, and the
corresponding VIN maximum must always be respected
3. All power (VDD) and ground (VSS) lines must always be connected to the external supply.
4. When several inputs are submitted to a current injection, the maximum ΣIINJ(PIN) is the absolute sum of the positive
and negative injected currents (instantaneous values). These results are based on characterization with ΣIINJ(PIN) maximum current injection on four I/O port pins of the device.
5. True open drain I/O port pins do not accept positive injection.
13.2.3 Thermal Characteristics
Symbol
TSTG
TJ
Ratings
Storage temperature range
Value
Unit
-65 to +150
°C
Maximum junction temperature: See section 14.2 on page 105 for TJmax
87/117
ST7260
13.3 OPERATING CONDITIONS
13.3.1 General Operating Conditions
Symbol
Parameter
Conditions
Min
Typ
Max
4
5
5.5
VDD
Operating Supply Voltage
VDDA
Analog supply voltage
VDD
VDD
VSSA
Analog supply voltage
VSS
VSS
fCPU
Operating frequency
TA
fCPU = 8 MHz
fOSC = 24 MHz
8
fOSC = 12 MHz
4
Ambient temperature range
0
Unit
V
MHz
70
°C
Figure 42. fCPU Maximum Operating Frequency Versus VDD Supply Voltage
fCPU [MHz]
8
FUNCTIONALITY
GUARANTEED
FROM 4 TO 5.5 V
4
FUNCTIONALITY
NOT GUARANTEED
IN THIS AREA
2
0
2.5
3.0
3.5
4
4.5
5
5.5 SUPPLY VOLTAGE [V]
13.3.2 Operating Conditions with Low Voltage Detector (LVD)
Subject to general operating conditions for VDD, fCPU, and TA. Refer to Figure 9 on page 20.
Symbol
VIT+
VITVhyst
VtPOR
Parameter
Conditions
Low Voltage Reset Threshold (VDD rising) VDD Max. Variation 50V/ms
Low Voltage Reset Threshold (VDD falling) VDD Max. Variation 50V/ms
Hysteresis (VIT+ - VIT-) 2)
VDD rise time rate 1)
Min
Typ
Max
Unit
3.4
3.2
100
3.7
3.5
175
4.0
3.8
220
V
V
mV
50
V/ms
0.5
Notes:
1. The VDD rise time rate condition is needed to insure a correct device power-on and LVD reset. Not tested in production.
2. Guaranteed by characterization - not tested in production
88/117
ST7260
13.4 SUPPLY CURRENT CHARACTERISTICS
The following current consumption specified for
the ST7 functional operating modes over temperature range does not take into account the clock
source current consumption. To get the total device consumption, the two current values must be
Symbol
Parameter
Conditions
∆IDD(∆Ta) Supply current variation vs. temperature
CPU RUN mode
IDD
added (except for HALT mode for which the clock
is stopped).
fCPU = 4 MHz
fCPU = 8 MHz
fCPU = 4 MHz
fCPU = 8 MHz
CPU WAIT mode
7.5
10.5
6
8.5
25
100
230
LVD disabled
LVD disabled
LVD enabled
USB Suspend mode 4)
Max
Unit
3)
Constant VDD and fCPU
I/Os in input mode
CPU HALT mode 2)
Typ
10
9 1)3)
13 1)
8 3)
11 1)
40 3)
120
%
mA
mA
µA
µA
Notes:
1. Oscillator and watchdog running. All others peripherals disabled.
2. USB Transceiver is powered down.
3. Not tested in production, guaranteed by characterization.
4. CPU in HALT mode. Current consumption of external pull-up (1.5Kohms to USBVCC) and pull-down (15Kohms to
VSSA) not included.
Figure 43. Typ. IDD in RUN at 4 and 8 MHz fCPU
Figure 44. Typ. IDD in WAIT at 4 and 8 MHz fCPU
Idd WFI (mA) at fcpu=4 and 8MHz
Idd Run (mA) at fcpu=4 and 8MHz
12
10
10
Idd WFI (mA)
Idd Run (mA)
8
8
6
6
4
4
8MHz
2
8MHz
2
4MHz
4MHz
0
0
4
4.2
4.4
4.6
4.8
Vdd (V)
5
5.2
5.4
4
4.2
4.4
4.6
4.8
5
5.2
5.4
Vdd (V)
89/117
ST7260
13.5 CLOCK AND TIMING CHARACTERISTICS
Subject to general operating conditions for VDD, fCPU, and TA.
13.5.1 General Timings
Symbol
tc(INST)
Parameter
Instruction cycle time
Conditions
fCPU=8MHz
2)
tv(IT)
Interrupt reaction time
tv(IT) = ∆tc(INST) + 10 tCPU
fCPU=8MHz
Min
Typ 1)
Max
Unit
2
3
12
tCPU
250
375
1500
ns
10
22
tCPU
1.25
2.75
µs
Notes:
1. Data based on typical application software.
2. Time measured between interrupt event and interrupt vector fetch. ∆tc(INST) is the number of tCPU cycles needed to finish
the current instruction execution.
13.5.2 CONTROL TIMING CHARACTERISTICS
CONTROL TIMINGS
Symbol
Parameter
Conditions
Value
Min
Typ.
Max
Unit
fOSC
Oscillator Frequency
24
MHz
fCPU
Operating Frequency
8
MHz
tRL
External RESET
Input pulse Width
2520
ns
tCPU
tPORL
Internal Power Reset Duration
4096
TDOGL
Watchdog or Low Voltage Reset
Output Pulse Width
200
tDOG
tOXOV
tDDR
Watchdog Time-out
fcpu = 8MHz
Crystal Oscillator
Start-up Time
Power up rise time
Note:
1. Not tested in production, guaranteed by characterization.
90/117
ns
49152
3145728
tCPU
6.144
393.216
ms
401)
ms
1001)
ms
201)
from VDD = 0 to 4V
300
30
ST7260
CLOCK AND TIMING CHARACTERISTICS (Cont’d)
13.5.3 External Clock Source
Symbol
Parameter
VOSCINH
OSCIN input pin high level voltage
Conditions
0.7xVDD
VDD
VOSCINL
OSCIN input pin low level voltage
VSS
0.3xVDD
tw(OSCINH)
OSCIN high or low time 1)
tw(OSCINL)
tr(OSCIN)
tf(OSCIN)
IL
Min
see Figure 45
Typ
Max
Unit
V
15
ns
OSCIN rise or fall time1)
15
OSCx Input leakage current
VSS≤VIN≤VDD
±1
µA
Note:
1. Data based on design simulation and/or technology characteristics, not tested in production.
Figure 45. Typical Application with an External Clock Source
90%
VOSCINH
10%
VOSCINL
tr(OSCIN)
tf(OSCIN)
tw(OSCINH)
OSCOUT
tw(OSCINL)
Not connected internally
fOSC
EXTERNAL
CLOCK SOURCE
IL
OSCIN
ST72XXX
Figure 46. Typical Application with a Crystal Resonator
i2
fOSC
CL1
OSCIN
RESONATOR
CL2
RF
OSCOUT
ST72XXX
91/117
ST7260
13.6 MEMORY CHARACTERISTICS
Subject to general operating conditions for fCPU, and TA unless otherwise specified.
13.6.1 RAM and Hardware Registers
Symbol
VRM
Parameter
Data retention mode 1)
Conditions
Min
HALT mode (or RESET)
2.0
Conditions
Read mode
Write / Erase mode,
TA=25°C
4.0V ≤VDD ≤ 5.5V
Write / Erase
Min
Typ
Max
Unit
V
Note:
1. Guaranteed by design. Not tested in production.
13.6.2 Flash Memory
Operating Conditions: fCPU = 8 MHz.
DUAL VOLTAGE FLASH MEMORY 1)
Symbol
Parameter
fCPU
Operating Frequency
VPP
IPP
tVPP
tRET
NRW
Programming Voltage
VPP Current
Internal VPP Stabilization Time
Data Retention
Write Erase Cycles
TA ≤ 55°C
TA=25°C
Typ
Max
8
8
11.4
12.6
30
10
40
100
Unit
MHz
V
mA
µs
years
cycles
Note:
1. Refer to the Flash Programming Reference Manual for the typical HDFlash programming and erase timing values.
Figure 47. Two typical Applications with VPP Pin1)
VPP
ST72XXX
Note:
1. When the ICP mode is not required by the application, VPP pin must be tied to VSS.
92/117
VPP
PROGRAMMING
TOOL
10kΩ
ST72XXX
ST7260
13.7 EMC CHARACTERISTICS
Susceptibility tests are performed on a sample basis during product characterization.
13.7.1 Functional EMS (Electro Magnetic
Susceptibility)
Based on a simple running application on the
product (toggling 2 LEDs through I/O ports), the
product is stressed by two electro magnetic events
until a failure occurs (indicated by the LEDs).
■ ESD: Electro-Static Discharge (positive and
negative) is applied on all pins of the device until
a functional disturbance occurs. This test
conforms with the IEC 1000-4-2 standard.
■ FTB: A Burst of Fast Transient voltage (positive
and negative) is applied to VDD and VSS through
a 100pF capacitor, until a functional disturbance
occurs. This test conforms with the IEC 1000-44 standard.
A device reset allows normal operations to be resumed. The test results are given in the table below based on the EMS levels and classes defined
in application note AN1709.
13.7.1.1 Designing hardened software to avoid
noise problems
EMC characterization and optimization are performed at component level with a typical applicaSymbol
tion environment and simplified MCU software. It
should be noted that good EMC performance is
highly dependent on the user application and the
software in particular.
Therefore it is recommended that the user applies
EMC software optimization and prequalification
tests in relation with the EMC level requested for
his application.
Software recommendations:
The software flowchart must include the management of runaway conditions such as:
– Corrupted program counter
– Unexpected reset
– Critical Data corruption (control registers...)
Prequalification trials:
Most of the common failures (unexpected reset
and program counter corruption) can be reproduced by manually forcing a low state on the RESET pin or the Oscillator pins for 1 second.
To complete these trials, ESD stress can be applied directly on the device, over the range of
specification values. When unexpected behaviour
is detected, the software can be hardened to prevent unrecoverable errors occurring (see application note AN1015).
Parameter
Level/
Class
Conditions
VFESD
Voltage limits to be applied on any I/O pin to induce VDD=5 V, TA=+25 °C, fOSC=8 MHz,
a functional disturbance
conforms to IEC 1000-4-2
4B
VFFTB
Fast transient voltage burst limits to be applied
through 100pF on VDD and VDD pins to induce a
functional disturbance
4A
VDD=5 V, TA=+25 °C, fOSC=8 MHz,
conforms to IEC 1000-4-4
13.7.2 Electro Magnetic Interference (EMI)
Based on a simple application running on the
product (toggling 2 LEDs through the I/O ports),
the product is monitored in terms of emission. This
emission test is in line with the norm SAE J 1752/
3 which specifies the board and the loading of
each pin.
Symbol
Parameter
Conditions
Monitored
Frequency Band
Max vs.
[fOSC/
fCPU]
Unit
16/8 MHz
SEMI
Peak level 1)
VDD=5V, TA=+25°C,
conforming to SAE J 1752/3
0.1MHz to 30MHz
30MHz to 130MHz
Note: Refer to Application Note AN1709 for 130MHz to 1GHz
data on other package types.
SAE EMI Level
36
39
dBµV
26
3.5
-
Note:
1. Data based on characterization results, not tested in production.
93/117
ST7260
EMC CHARACTERISTICS (Cont’d)
13.7.3 Absolute Maximum Ratings (Electrical
Sensitivity)
Based on three different tests (ESD, LU and DLU)
using specific measurement methods, the product
is stressed in order to determine its performance in
terms of electrical sensitivity. For more details, refer to the application note AN1181.
13.7.3.1 Electro-Static Discharge (ESD)
Electro-Static Discharges (a positive then a negative pulse separated by 1 second) are applied to
the pins of each sample according to each pin
combination. The sample size depends on the
number of supply pins in the device (3 parts*(n+1)
supply pin). This test conforms to the JESD22A114A/A115A standard.
Absolute Maximum Ratings
Symbol
VESD(HBM)
Ratings
Electro-static discharge voltage
(Human Body Model)
Conditions
TA=+25°C
Maximum value 1) Unit
2000
V
Note:
1. Data based on characterization results, not tested in production.
13.7.3.2 Static and Dynamic Latch-Up
■ LU: 3 complementary static tests are required
on 10 parts to assess the latch-up performance.
A supply overvoltage (applied to each power
supply pin) and a current injection (applied to
each input, output and configurable I/O pin) are
performed on each sample. This test conforms
to the EIA/JESD 78 IC latch-up standard. For
more details, refer to the application note
AN1181.
■
DLU: Electro-Static Discharges (one positive
then one negative test) are applied to each pin
of 3 samples when the micro is running to
assess the latch-up performance in dynamic
mode. Power supplies are set to the typical
values, the oscillator is connected as near as
possible to the pins of the micro and the
component is put in reset mode. This test
conforms to the IEC1000-4-2 and SAEJ1752/3
standards. For more details, refer to the
application note AN1181.
Electrical Sensitivities
Symbol
LU
DLU
Parameter
Conditions
Class 1)
Static latch-up class
TA=+25°C
A
Dynamic latch-up class
VDD=5.5V, fOSC=4MHz, TA=+25°C
A
Note:
1. Class description: A Class is an STMicroelectronics internal specification. All its limits are higher than the JEDEC specifications, that means when a device belongs to Class A it exceeds the JEDEC standard. B Class strictly covers all the
JEDEC criteria (international standard).
94/117
ST7260
13.8 I/O PORT PIN CHARACTERISTICS
13.8.1 General Characteristics
Subject to general operating conditions for VDD, fCPU, and TA unless otherwise specified.
Symbol
Parameter
Conditions
VIL
Input low level voltage
VIH
Input high level voltage
VIN
Input voltage
Vhys
Schmitt trigger voltage hysteresis
Min
Typ
Max
0.3xVDD
0.7xVDD
True open drain I/O pins
Other I/O pins
6.0
VSS
VDD
400
VSS≤VIN≤VDD
IL
Input leakage current
IS
Static current consumption induced
Floating input mode
by each floating input pin 1)
RPU
Weak pull-up equivalent resistor 2)
CIO
VIN=VSS
Unit
V
V
mV
±1
µA
400
VDD=5 V
50
90
I/O pin capacitance
5
tf(IO)out
Output high to low level fall time
25
tr(IO)out
Output low to high level rise time
tw(IT)in
External interrupt pulse time 3)
CL=50 pF
Between 10% and 90%
25
1
120
kΩ
pF
ns
tCPU
Notes:
1. Configuration not recommended, all unused pins must be kept at a fixed voltage: using the output mode of the I/O for
example or an external pull-up or pull-down resistor (see Figure 48). Static peak current value taken at a fixed VIN value,
based on design simulation and technology characteristics, not tested in production. This value depends on VDD and temperature values.
2. The RPU pull-up equivalent resistor is based on a resistive transistor (corresponding IPU current characteristics described in Figure 49).
3. To generate an external interrupt, a minimum pulse width has to be applied on an I/O port pin configured as an external
interrupt source.
Figure 48. Two typical Applications with unused I/O Pin
VDD
ST72XXX
10kΩ
10kΩ
UNUSED I/O PORT
UNUSED I/O PORT
ST72XXX
Figure 49. Typ. IPU vs. VDD
Pull-up current (µA)
90
80
Pull-up current (µA)
70
60
50
40
30
20
10
0
4
4.2
4.4
4.6
4.8
5
5.2
5.4
Vdd (V)
95/117
ST7260
Figure 50. Typ. RPU vs. VDD
Rpu (KOhm)
140
120
Rpu (KOhm)
100
80
60
40
20
0
4
4.2
4.4
4.6
4.8
5
5.2
5.4
Vdd (V)
13.8.2 Output Driving Current
Subject to general operating condition for VDD, fCPU, and TA unless otherwise specified.
Symbol
Conditions
Max
0.4
Output low level voltage for a high sink I/O pin
when up to 4 pins are sunk at the same time, Port
B(0:7)
IIO=+10 mA
1.3
Output low level voltage for a very high sink I/O
pin when up to 2 pins are sunk at the same time,
Port A1, Port A2
VOH 2)
Min
IIO=+1.6 mA
VDD=5 V
VOL 1)
Parameter
Output low level voltage for a standard I/O pin
when up to 8 pins are sunk at the same time, Port
A0, Port A(3:7), Port C(0:2)
V
IIO=+25 mA
1.5
IIO=-10 mA
Output high level voltage for an I/O pin
when up to 8 pins are sourced at same time
Unit
VDD-1.3
IIO=-1.6 mA VDD-0.8
Notes:
1. The IIO current sunk must always respect the absolute maximum rating specified in Section 13.2 and the sum of IIO (I/
O ports and control pins) must not exceed IVSS.
2. The IIO current sourced must always respect the absolute maximum rating specified in Section 13.2 and the sum of IIO
(I/O ports and control pins) must not exceed IVDD. True open drain I/O pins does not have VOH.
Figure 51. VOL standard VDD=5 V
Figure 52. VOL high sink VDD=5 V
Vol_2mA (mV) at Vdd=5V
Vol_10mA (V) at Vdd=5V
250
1.6
1.4
200
Vol_10mA (V)
Vol_2mA (mV)
1.2
150
100
1
0.8
0.6
50
0.4
0
0.2
1
1.5
2
2.5
Iio (mA)
96/117
3
3.5
4
5
7
9
11
13
Iio (mA)
15
17
19
ST7260
Figure 53. VOL very high sink VDD=5 V
Figure 55. VOL high sink vs. VDD
Vol_25mA (V) at Vdd=5V
Vol_10mA (V) at Iio=10mA
0.6
0.95
0.59
0.58
0.85
Vol_10mA (V)
Vol_25mA (V)
0.57
0.75
0.65
0.55
0.56
0.55
0.54
0.53
0.52
0.45
0.51
0.5
0.35
15
20
25
30
4
35
4.2
4.4
4.6
Figure 54. VOL standard vs. VDD
5
5.2
5.4
Figure 56. VOL very high sink vs. VDD
Vol_25mA (V) at Iio=25mA
Vol_2mA (mV) at Iio=2mA
0.8
130
125
0.75
Vol_25mA (V)
Vol_2mA (mV)
4.8
Vdd (V)
Iio (mA)
120
115
0.7
0.65
110
0.6
105
4
4.2
4.4
4.6
4.8
5
5.2
4
5.4
4.2
4.4
4.6
4.8
5
5.2
5.4
Vdd (V)
Vdd (V)
Figure 57. |VDD-VOH| @ VDD=5 V (low current)
Figure 58. |VDD-VOH| @ VDD=5 V (high current)
|Vdd - Voh| (V) at Vdd=5V
|Vdd - Voh| (V) at Vdd=5V
0.3
2
1.8
0.25
1.4
0.2
|Vdd - Voh| (V)
|Vdd - Voh| (V)
1.6
0.15
0.1
1.2
1
0.8
0.6
0.4
0.05
0.2
0
0
1
1.5
2
2.5
-Iio (mA)
3
3.5
4
2
7
12
17
-Iio (mA)
97/117
ST7260
Figure 59. |VDD-VOH| @ IIO=2 mA (low current)
Figure 60. |VDD-VOH| @ IIO=10mA (high current)
|Vdd - Voh| (V) at Iio=-10mA
0.9
0.16
0.8
0.155
0.7
0.15
0.6
|Vdd - Voh| (V)
|Vdd - Voh| (V)
|Vdd - Voh| (V) at Iio=-2mA
0.165
0.145
0.14
0.135
0.5
0.4
0.3
0.13
0.2
0.125
0.1
0.12
0
4
4.2
4.4
4.6
4.8
Vdd (V)
98/117
5
5.2
5.4
4
4.2
4.4
4.6
4.8
Vdd (V)
5
5.2
5.4
ST7260
13.9 CONTROL PIN CHARACTERISTICS
13.9.1 Asynchronous RESET Pin
Subject to general operating conditions for VDD, fCPU, and TA unless otherwise specified.
Symbol
Parameter
VIH
Input High Level Voltage
VIL
Input Low Voltage
Vhys
Schmitt trigger voltage hysteresis 1)
VOL
Output low level voltage 2)
RON
Weak pull-up equivalent resistor 3)
tw(RSTL)out Generated reset pulse duration
th(RSTL)in
External reset pulse hold time 4)
Conditions
Min
Typ
Max
Unit
0.7xVDD
VDD
V
VSS
0.3xVDD
400
VDD=5V
VIN=VSS
IIO=5 mA
0.8
IIO=7.5 mA
1.3
VDD=5 V
50
External pin or
internal reset sources
80
6
30
5
V
mV
100
V
kΩ
1/fSFOSC
µs
µs
Notes:
1. Hysteresis voltage between Schmitt trigger switching levels. Based on characterization results, not tested.
2. The IIO current sunk must always respect the absolute maximum rating specified in Section 13.2 and the sum of IIO (I/
O ports and control pins) must not exceed IVSS.
3. The RON pull-up equivalent resistor is based on a resistive transistor. This data is based on characterization results,
not tested in production.
4. To guarantee the reset of the device, a minimum pulse has to be applied to RESET pin. All short pulses applied on
RESET pin with a duration below th(RSTL)in can be ignored.
99/117
ST7260
CONTROL PIN CHARACTERISTICS (Cont’d)
Figure 61. RESET pin protection when LVD is enabled.1)2)3)4)
VDD
Required
Optional
(note 6)
ST72XXX
RON
EXTERNAL
RESET
INTERNAL
RESET
Filter
0.01 µF
1 MΩ
PULSE
GENERATOR
WATCHDOG
LVD RESET
Figure 62. RESET pin protection when LVD is disabled.1)
Recommended for EMC
VDD
USER
EXTERNAL
RESET
CIRCUIT
VDD
ST72XXX
VDD
0.0 1µF
4.7 kΩ
RON
INTERNAL
RESET
Filter
0.01 µF
PULSE
GENERATOR
WATCHDOG
Required
Note 1:
– The reset network protects the device against parasitic resets.
– The output of the external reset circuit must have an open-drain output to drive the ST7 reset pad. Otherwise the
device can be damaged when the ST7 generates an internal reset (LVD or watchdog).
– Whatever the reset source is (internal or external), the user must ensure that the level on the RESET pin can go
below the VIL max. level specified in section 13.9.1 on page 99. Otherwise the reset will not be taken into account
internally.
– Because the reset circuit is designed to allow the internal RESET to be output in the RESET pin, the user must ensure that the current sunk on the RESET pin is less than the absolute maximum value specified for IINJ(RESET) in
section 13.2.2 on page 87.
Note 2: When the LVD is enabled, it is recommended not to connect a pull-up resistor or capacitor. A 10nF pull-down
capacitor is required to filter noise on the reset line.
Note 3: In case a capacitive power supply is used, it is recommended to connect a 1 MΩ pull-down resistor to the RESET
pin to discharge any residual voltage induced by the capacitive effect of the power supply (this will add 5µA to the power
consumption of the MCU).
Note 4: Tips when using the LVD:
– 1. Check that all recommendations related to ICCCLK and reset circuit have been applied (see notes above).
– 2. Check that the power supply is properly decoupled (100 nF + 10 µF close to the MCU). Refer to AN1709 and
AN2017. If this cannot be done, it is recommended to put a 100 nF + 1MΩ pull-down on the RESET pin.
– 3. The capacitors connected on the RESET pin and also the power supply are key to avoid any start-up marginality.
In most cases, steps 1 and 2 above are sufficient for a robust solution. Otherwise: replace 10 nF pull-down on the
RESET pin with a 5 µF to 20 µF capacitor.”
100/117
ST7260
13.10 COMMUNICATION INTERFACE CHARACTERISTICS
13.10.1 USB - Universal Bus Interface
(Operating conditions TA = 0 to +70°C, VDD = 4.0 to 5.25V unless otherwise specified)
USB DC Electrical Characteristics
Symbol
Parameter
Conditions
Min.
Max.
VDI
Differential Input Sensitivity
I(D+, D-)
0.2
VCM
Differential Common Mode
Range
Includes VDI range
0.8
2.5
VSE
Single Ended Receiver Threshold
0.8
2.0
VOL
Static Output Low
RL 1) of 1.5 Kohms to
3.6v
VOH
Static Output High
RL 1) of 15 Kohms to
VSS
2.8
3.6
VDD=5 V
3.00
3.60
USBV
USBVCC: voltage level
3)
0.3
Unit
V 2)
Notes:
1. RL is the load connected on the USB drivers.
2. All the voltages are measured from the local ground potential.
3. To improve EMC performance (noise immunity), it is recommended to connect a 100nF capacitor to the USBVCC pin.
Figure 63. USB: Data Signal Rise and Fall Time
Differential
Data Lines
Crossover
points
VCRS
VSS
tr
tf
Table 24. USB: Low-speed Electrical Characteristics
Symbol
Parameter
Conditions
Min
Max
Unit
Driver characteristics:
tr
tf
Rise time
Fall Time
trfm
Rise/ Fall Time matching
VCRS
Output signal Crossover
Voltage
CL=50 pF 1)
CL=600 pF
75
1)
CL=50 pF 1)
300
ns
300
ns
80
120
%
1.3
2.0
V
75
CL=600 pF 1)
tr/tf
ns
ns
Note:
1. For more detailed information, please refer to Chapter 7 (Electrical) of the USB specification (version 1.1).
101/117
ST7260
COMMUNICATION INTERFACE CHARACTERISTICS (Cont’d)
13.10.2 SCI - Serial Communications Interface
Subject to general operating condition for VDD, fCPU, and TA unless otherwise specified.
Refer to I/O port characteristics for more details on the input/output alternate function characteristics (RDI
and TDO).
Conditions
Symbol
Parameter
fCPU
fTx
fRx
102/117
Accuracy
vs. Standard
Communication frequency 8 MHz ~0.16%
Prescaler
Conventional Mode
TR (or RR)=128, PR=13
TR (or RR)= 32, PR=13
TR (or RR)= 16, PR=13
TR (or RR)= 8, PR=13
TR (or RR)= 4, PR=13
TR (or RR)= 16, PR= 3
TR (or RR)= 2, PR=13
TR (or RR)= 1, PR=13
Standard
Baud
Rate
300
~300.48
1200 ~1201.92
2400 ~2403.84
4800 ~4807.69
9600 ~9615.38
10400 ~10416.67
19200 ~19230.77
38400 ~38461.54
Unit
Hz
ST7260
14 PACKAGE CHARACTERISTICS
In order to meet environmental requirements, ST
offers these devices in ECOPACK® packages.
These packages have a Lead-free second level interconnect. The category of second Level Interconnect is marked on the package and on the inner box label, in compliance with JEDEC Standard
JESD97. The maximum ratings related to soldering conditions are also marked on the inner box label.
ECOPACK is an ST trademark. ECOPACK specifications are available at: www.st.com
14.1 PACKAGE MECHANICAL DATA
Figure 64. 24-Pin Plastic Small Outline Package, 300-mil Width
Dim.
D
h x 45×
L
A1
A
C
a
B
e
mm
Min
H
inches
Max
Min
Typ
Max
A
2.35
2.65 0.093
0.104
A1
0.10
0.30 0.004
0.012
B
0.33
0.51 0.013
0.020
C
0.23
0.32 0.009
0.013
D
15.20
15.60 0.599
0.614
E
7.40
7.60 0.291
0.299
e
E
Typ
1.27
0.050
H
10.00
10.65 0.394
0.419
h
0.25
0.75 0.010
0.030
α
0°
L
0.40
8°
0°
1.27 0.016
8°
0.050
Number of Pins
N
24
103/117
ST7260
A2
Figure 65. 40-Lead Very thin Fine pitch Quad Flat No-Lead Package
A
SEATING
A3
PLANE
Dim.
A1
D
E2
E
Typ
Max
0.90
1.00 0.031 0.035 0.039
A1
0.02
0.05
0.001 0.002
A2
0.65
1.00
0.026 0.039
A3
0.20
Min
Typ
Max
0.008
b
0.18
0.25
D
5.85
6.00
6.15 0.230 0.236 0.242
D2
2.75
2.9
3.05 0.108 0.114 0.120
E
5.85
6
6.15 0.230 0.236 0.242
E2
2.75
2.9
3.05 0.108 0.114 0.120
e
PIN #1 ID TYPE C
RADIUS
L
0.50
0.30
0.40
0.30 0.007 0.010 0.012
0.020
0.50 0.012 0.016 0.020
Number of Pins
2
1
N
40
Note 1. Values in inches are converted from mm
and rounded to 3 decimal digits.
L
b
104/117
Min
0.80
A
D2
inches1)
mm
e
ST7260
14.2 THERMAL CHARACTERISTICS
Symbol
Ratings
Value
Unit
70
34
°C/W
500
mW
150
°C
Package thermal resistance (junction to ambient)
SO24
QFN40
RthJA
PD
TJmax
Power dissipation 1)
Maximum junction temperature
2)
Notes:
1. The power dissipation is obtained from the formula PD=PINT+PPORT where PINT is the chip internal power (IDDxVDD)
and PPORT is the port power dissipation determined by the user.
2. The average chip-junction temperature can be obtained from the formula TJ = TA + PD x RthJA.
105/117
ST7260
14.3 SOLDERING AND GLUEABILITY INFORMATION
Recommended soldering information given only
as design guidelines in Figure 66 and Figure 67.
Recommended glue for SMD plastic packages
dedicated to molding compound with silicone:
■ Heraeus: PD945, PD955
■ Loctite: 3615, 3298
Figure 66. Recommended Wave Soldering Profile (with 37% Sn and 63% Pb)
250
200
150
SOLDERING
PHASE
80°C
Temp. [°C]
100
50
COOLING PHASE
(ROOM TEMPERATURE)
5 sec
PREHEATING
PHASE
Time [sec]
0
20
40
60
80
100
120
140
160
Figure 67. Recommended Reflow Soldering Oven Profile (MID JEDEC)
250
Tmax=220+/-5°C
for 25 sec
200
150
90 sec at 125°C
150 sec above 183°C
Temp. [°C]
100
50
ramp down natural
2°C/sec max
ramp up
2°C/sec for 50sec
Time [sec]
0
100
106/117
200
300
400
ST7260
15 DEVICE CONFIGURATION AND ORDERING INFORMATION
Each device is available for production in user programmable versions (High Density FLASH) as
well as in factory coded versions (FASTROM).
ST72P60 devices are Factory Advanced Service
Technique ROM (FASTROM) versions: they are
factory programmed FLASH devices.
ST72F60 FLASH devices are shipped to customers with a default content (FFh).
This implies that FLASH devices have to be configured by the customer using the Option Byte
while the ROM devices are factory-configured.
when entering HALT mode while the Watchdog is
active.
0: No Reset generation when entering Halt mode
1: Reset generation when entering Halt mode
15.1 OPTION BYTE
OPT 2 = Reserved.
The Option Byte allows the hardware configuration
of the microcontroller to be selected.
The Option Byte has no address in the memory
map and can be accessed only in programming
mode using a standard ST7 programming tool.
The default contents of the FLASH is fixed to F7h.
This means that all the options have “1” as their
default value, except LVD.
In ROM devices, the Option Byte is fixed in hardware by the ROM code.
OPTION BYTE
7
--
0
--
WDG WD
SW HALT
LVD
--
OSC FMP_
24/12
R
OPT 7:6 = Reserved.
OPT 5 = WDGSW Hardware or Software Watchdog
This option bit selects the watchdog type.
0: Hardware enabled
1: Software enabled
OPT 3 = LVD Low Voltage Detector selection
This option bit selects the LVD.
0: LVD enabled
1: LVD disabled
Important note: on ROM devices this option bit is
forced by ST to 0 (LVD always enabled):
OPT 1 = OSC24/12 Oscillator Selection
This option bit selects the clock divider used to
drive the USB interface at 6MHz.
0: 24 MHz oscillator
1: 12 Mhz oscillator
OPT 0 = FMP_R Flash memory read-out protection
This option indicates if the user flash memory is
protected against read-out. Read-out protection,
when selected, provides a protection against Program Memory content extraction and against write
access to Flash memory. Erasing the option bytes
when the FMP_R option is selected, causes the
whole user memory to be erased first and the device can be reprogrammed. Refer to the ST7 Flash
Programming Reference Manual and section 4.3.1
on page 14 for more details.
0: Read-out protection enabled
1: Read-out protection disabled
OPT 4 = WDHALT Watchdog and HALT mode
This option bit determines if a RESET is generated
107/117
ST7260
15.2 DEVICE ORDERING INFORMATION AND TRANSFER OF CUSTOMER CODE
Customer code is made up of the FASTROM contents and the list of the selected options (if any).
The FASTROM contents are to be sent on diskette, or by electronic means, with the hexadecimal file in .S19 format generated by the development tool. All unused bytes must be set to FFh.
The selected options are communicated to STMicroelectronics using the correctly completed OPTION LIST appended. See page 110.
Refer to application note AN1635 for information
on the counter listing returned by ST after code
has been transferred.
The STMicroelectronics Sales Organization will be
pleased to provide detailed information on contractual points.
Table 25. Supported Part Numbers
Sales Type 1)
ST72F60K2U1
ST72F60E2M1
ST72F60K1U1
ST72F60E1M1
ST7260K2U1/xxx
ST7260E2M1/xxx
ST7260K1U1/xxx
ST7260E1M1/xxx
ST72P60K2U1
ST72P60E2M1
ST72P60K1U1
ST72P60E1M1
Program Memory
(bytes)
8 K Flash
4 K Flash
8 K ROM
4 K ROM
8 K FASTROM
4 K FASTROM
RAM
(bytes)
384
384
384
384
384
384
384
384
384
384
384
384
Note:
Contact ST sales office for product availability
1. /xxx stands for the ROM code name assigned by STMicroelectronics
108/117
Package
QFN40
SO24
QFN40
SO24
QFN40
SO24
QFN40
SO24
QFN40
SO24
QFN40
SO24
ST7260
15.3 DEVELOPMENT TOOLS
STMicroelectronics offers a range of hardware
and software development tools for the ST7 microcontroller family. Full details of tools available for
the ST7 from third party manufacturers can be obtain from the STMicroelectronics Internet site:
➟ http//www.st.com.
Tools from these manufacturers include C compliers, emulators and gang programmers.
STMicroelectronics Tools
Three types of development tool are offered by ST
see Table 26 and Table 27 for more details.
Table 26. STMicroelectronics Tools Features
In-Circuit Emulation
ST7 Emulator
Yes, powerful emulation
features including trace/
logic analyzer
ST7 Programming Board No
Programming Capability1)
Software Included
ST7 CD ROM with:
No
Yes (All packages)
– ST7 Assembly toolchain
– STVD7 powerful Source Level
Debugger for Win 3.1, Win 9x
and NT
– C compiler demo versions
– Windows Programming Tools
for Win 3.1, Win 9x and NT
Note:
1. In-Circuit Programming (ICP) interface for FLASH devices.
Table 27. Dedicated STMicroelectronics Development Tools
Supported Products
Evaluation Board
ST7 Emulator
ST7 Programming Board
ST7260
ST7MDTULS-EVAL
ST7MDTU3-EMU3
ST7MDTU3-EPB 1)
Note:
1. Add Suffix /EU or /US for the power supply for your region.
109/117
ST7260
ST7260 MICROCONTROLLER OPTION LIST
(Last update: Oct 2006)
Customer:
Address:
Contact:
Phone No:
Reference:
............................................................................
............................................................................
............................................................................
............................................................................
............................................................................
............................................................................
ROM or FASTROM code must be sent in .S19 format.
Hex extension cannot be processed.
STMicroelectronics references:
Device Type/Memory Size/Package (check only one option):
----------------------------------------------------------------------------------------ROM DEVICE: |
4K
|
8K
|
----------------------------------------------------------------------------------------SO24:
| [ ] ST7260E1M1
| [ ] ST7260E2M1
|
QFN40:
| [ ] ST7260K1U1
| [ ] ST7260K2U1
|
-----------------------------------------------------------------------------------------FASTROM: |
4K
|
8K
|
-----------------------------------------------------------------------------------------SO24:
| [ ] ST72P60E1M1
| [ ] ST72P60E2M1 |
QFN40:
| [ ] ST72P60K1U1
| [ ] ST72P60K2U1 |
-----------------------------------------------------------------------------------------DIE FORM: |
4K
|
8K
|
-----------------------------------------------------------------------------------------24-pin:
| [ ] (as E1M1)
| [ ] (as E2M1)
|
40-pin:
| [ ] (as K1U1)
| [ ] (as K2U1)
|
Conditioning (check only one option):
Packaged Product
|
Die Product (ROM only. Dice tested at 25°C only)
-----------------------------------------------------------------------------------------------------------------------[ ] Tape & Reel (SO package only)
|
[ ] Tape & Reel
[ ] Tube
|
[ ] Inked wafer
|
[ ] Sawn wafer on sticky foil
Special Marking ( ROM only): [ ] No
[ ] Yes "_ _ _ _ _ _ _ _ _ _ _ _ _"
Authorized characters are letters, digits, '.', '-', '/' and spaces only.
For marking, one line is possible with a maximum of 13 characters.
Watchdog Selection:
[ ] Software activation [ ] Hardware activation
Halt when Watchdog on: [ ] Reset
[ ] No reset
LVD Reset *
[ ] Disabled*
[ ] Enabled*
* LVD is forced to 0 (LVD always enabled) on ROM devices
Oscillator Selection:
Readout Protection:
Date
[ ] 24 MHz.
[ ] Disabled
[ ] 12 MHz.
[ ] Enabled
............................................................................
Signature
............................................................................
Please download the latest version of this option list from:
http://www.st.com/mcu > downloads > ST7 microcontrollers > Option list
110/117
ST7260
15.4 ST7 APPLICATION NOTES
Table 28. ST7 Application Notes
IDENTIFICATION DESCRIPTION
APPLICATION EXAMPLES
AN1658
SERIAL NUMBERING IMPLEMENTATION
AN1720
MANAGING THE READ-OUT PROTECTION IN FLASH MICROCONTROLLERS
AN1755
A HIGH RESOLUTION/PRECISION THERMOMETER USING ST7 AND NE555
AN1756
CHOOSING A DALI IMPLEMENTATION STRATEGY WITH ST7DALI
A HIGH PRECISION, LOW COST, SINGLE SUPPLY ADC FOR POSITIVE AND NEGATIVE INAN1812
PUT VOLTAGES
EXAMPLE DRIVERS
AN 969
SCI COMMUNICATION BETWEEN ST7 AND PC
AN 970
SPI COMMUNICATION BETWEEN ST7 AND EEPROM
AN 971
I²C COMMUNICATION BETWEEN ST7 AND M24CXX EEPROM
AN 972
ST7 SOFTWARE SPI MASTER COMMUNICATION
AN 973
SCI SOFTWARE COMMUNICATION WITH A PC USING ST72251 16-BIT TIMER
AN 974
REAL TIME CLOCK WITH ST7 TIMER OUTPUT COMPARE
AN 976
DRIVING A BUZZER THROUGH ST7 TIMER PWM FUNCTION
AN 979
DRIVING AN ANALOG KEYBOARD WITH THE ST7 ADC
AN 980
ST7 KEYPAD DECODING TECHNIQUES, IMPLEMENTING WAKE-UP ON KEYSTROKE
AN1017
USING THE ST7 UNIVERSAL SERIAL BUS MICROCONTROLLER
AN1041
USING ST7 PWM SIGNAL TO GENERATE ANALOG OUTPUT (SINUSOÏD)
AN1042
ST7 ROUTINE FOR I²C SLAVE MODE MANAGEMENT
AN1044
MULTIPLE INTERRUPT SOURCES MANAGEMENT FOR ST7 MCUS
AN1045
ST7 S/W IMPLEMENTATION OF I²C BUS MASTER
AN1046
UART EMULATION SOFTWARE
AN1047
MANAGING RECEPTION ERRORS WITH THE ST7 SCI PERIPHERALS
AN1048
ST7 SOFTWARE LCD DRIVER
AN1078
PWM DUTY CYCLE SWITCH IMPLEMENTING TRUE 0% & 100% DUTY CYCLE
AN1082
DESCRIPTION OF THE ST72141 MOTOR CONTROL PERIPHERALS REGISTERS
AN1083
ST72141 BLDC MOTOR CONTROL SOFTWARE AND FLOWCHART EXAMPLE
AN1105
ST7 PCAN PERIPHERAL DRIVER
AN1129
PWM MANAGEMENT FOR BLDC MOTOR DRIVES USING THE ST72141
AN INTRODUCTION TO SENSORLESS BRUSHLESS DC MOTOR DRIVE APPLICATIONS
AN1130
WITH THE ST72141
AN1148
USING THE ST7263 FOR DESIGNING A USB MOUSE
AN1149
HANDLING SUSPEND MODE ON A USB MOUSE
AN1180
USING THE ST7263 KIT TO IMPLEMENT A USB GAME PAD
AN1276
BLDC MOTOR START ROUTINE FOR THE ST72141 MICROCONTROLLER
AN1321
USING THE ST72141 MOTOR CONTROL MCU IN SENSOR MODE
AN1325
USING THE ST7 USB LOW-SPEED FIRMWARE V4.X
AN1445
EMULATED 16-BIT SLAVE SPI
AN1475
DEVELOPING AN ST7265X MASS STORAGE APPLICATION
AN1504
STARTING A PWM SIGNAL DIRECTLY AT HIGH LEVEL USING THE ST7 16-BIT TIMER
AN1602
16-BIT TIMING OPERATIONS USING ST7262 OR ST7263B ST7 USB MCUS
AN1633
DEVICE FIRMWARE UPGRADE (DFU) IMPLEMENTATION IN ST7 NON-USB APPLICATIONS
AN1712
GENERATING A HIGH RESOLUTION SINEWAVE USING ST7 PWMART
AN1713
SMBUS SLAVE DRIVER FOR ST7 I2C PERIPHERALS
AN1753
SOFTWARE UART USING 12-BIT ART
111/117
ST7260
Table 28. ST7 Application Notes
IDENTIFICATION DESCRIPTION
AN1947
ST7MC PMAC SINE WAVE MOTOR CONTROL SOFTWARE LIBRARY
GENERAL PURPOSE
AN1476
LOW COST POWER SUPPLY FOR HOME APPLIANCES
AN1526
ST7FLITE0 QUICK REFERENCE NOTE
AN1709
EMC DESIGN FOR ST MICROCONTROLLERS
AN1752
ST72324 QUICK REFERENCE NOTE
PRODUCT EVALUATION
AN 910
PERFORMANCE BENCHMARKING
AN 990
ST7 BENEFITS VS INDUSTRY STANDARD
AN1077
OVERVIEW OF ENHANCED CAN CONTROLLERS FOR ST7 AND ST9 MCUS
AN1086
U435 CAN-DO SOLUTIONS FOR CAR MULTIPLEXING
AN1103
IMPROVED B-EMF DETECTION FOR LOW SPEED, LOW VOLTAGE WITH ST72141
AN1150
BENCHMARK ST72 VS PC16
AN1151
PERFORMANCE COMPARISON BETWEEN ST72254 & PC16F876
AN1278
LIN (LOCAL INTERCONNECT NETWORK) SOLUTIONS
PRODUCT MIGRATION
AN1131
MIGRATING APPLICATIONS FROM ST72511/311/214/124 TO ST72521/321/324
AN1322
MIGRATING AN APPLICATION FROM ST7263 REV.B TO ST7263B
AN1365
GUIDELINES FOR MIGRATING ST72C254 APPLICATIONS TO ST72F264
AN1604
HOW TO USE ST7MDT1-TRAIN WITH ST72F264
AN2200
GUIDELINES FOR MIGRATING ST7LITE1X APPLICATIONS TO ST7FLITE1XB
PRODUCT OPTIMIZATION
AN 982
USING ST7 WITH CERAMIC RESONATOR
AN1014
HOW TO MINIMIZE THE ST7 POWER CONSUMPTION
AN1015
SOFTWARE TECHNIQUES FOR IMPROVING MICROCONTROLLER EMC PERFORMANCE
AN1040
MONITORING THE VBUS SIGNAL FOR USB SELF-POWERED DEVICES
AN1070
ST7 CHECKSUM SELF-CHECKING CAPABILITY
AN1181
ELECTROSTATIC DISCHARGE SENSITIVE MEASUREMENT
AN1324
CALIBRATING THE RC OSCILLATOR OF THE ST7FLITE0 MCU USING THE MAINS
AN1502
EMULATED DATA EEPROM WITH ST7 HDFLASH MEMORY
AN1529
EXTENDING THE CURRENT & VOLTAGE CAPABILITY ON THE ST7265 VDDF SUPPLY
ACCURATE TIMEBASE FOR LOW-COST ST7 APPLICATIONS WITH INTERNAL RC OSCILLAAN1530
TOR
AN1605
USING AN ACTIVE RC TO WAKEUP THE ST7LITE0 FROM POWER SAVING MODE
AN1636
UNDERSTANDING AND MINIMIZING ADC CONVERSION ERRORS
AN1828
PIR (PASSIVE INFRARED) DETECTOR USING THE ST7FLITE05/09/SUPERLITE
AN1946
SENSORLESS BLDC MOTOR CONTROL AND BEMF SAMPLING METHODS WITH ST7MC
AN1953
PFC FOR ST7MC STARTER KIT
AN1971
ST7LITE0 MICROCONTROLLED BALLAST
PROGRAMMING AND TOOLS
AN 978
ST7 VISUAL DEVELOP SOFTWARE KEY DEBUGGING FEATURES
AN 983
KEY FEATURES OF THE COSMIC ST7 C-COMPILER PACKAGE
AN 985
EXECUTING CODE IN ST7 RAM
AN 986
USING THE INDIRECT ADDRESSING MODE WITH ST7
AN 987
ST7 SERIAL TEST CONTROLLER PROGRAMMING
AN 988
STARTING WITH ST7 ASSEMBLY TOOL CHAIN
AN1039
ST7 MATH UTILITY ROUTINES
112/117
ST7260
Table 28. ST7 Application Notes
IDENTIFICATION
AN1071
AN1106
DESCRIPTION
HALF DUPLEX USB-TO-SERIAL BRIDGE USING THE ST72611 USB MICROCONTROLLER
TRANSLATING ASSEMBLY CODE FROM HC05 TO ST7
PROGRAMMING ST7 FLASH MICROCONTROLLERS IN REMOTE ISP MODE (IN-SITU PROAN1179
GRAMMING)
AN1446
USING THE ST72521 EMULATOR TO DEBUG AN ST72324 TARGET APPLICATION
AN1477
EMULATED DATA EEPROM WITH XFLASH MEMORY
AN1527
DEVELOPING A USB SMARTCARD READER WITH ST7SCR
AN1575
ON-BOARD PROGRAMMING METHODS FOR XFLASH AND HDFLASH ST7 MCUS
AN1576
IN-APPLICATION PROGRAMMING (IAP) DRIVERS FOR ST7 HDFLASH OR XFLASH MCUS
AN1577
DEVICE FIRMWARE UPGRADE (DFU) IMPLEMENTATION FOR ST7 USB APPLICATIONS
AN1601
SOFTWARE IMPLEMENTATION FOR ST7DALI-EVAL
AN1603
USING THE ST7 USB DEVICE FIRMWARE UPGRADE DEVELOPMENT KIT (DFU-DK)
AN1635
ST7 CUSTOMER ROM CODE RELEASE INFORMATION
AN1754
DATA LOGGING PROGRAM FOR TESTING ST7 APPLICATIONS VIA ICC
AN1796
FIELD UPDATES FOR FLASH BASED ST7 APPLICATIONS USING A PC COMM PORT
AN1900
HARDWARE IMPLEMENTATION FOR ST7DALI-EVAL
AN1904
ST7MC THREE-PHASE AC INDUCTION MOTOR CONTROL SOFTWARE LIBRARY
AN1905
ST7MC THREE-PHASE BLDC MOTOR CONTROL SOFTWARE LIBRARY
SYSTEM OPTIMIZATION
AN1711
SOFTWARE TECHNIQUES FOR COMPENSATING ST7 ADC ERRORS
AN1827
IMPLEMENTATION OF SIGMA-DELTA ADC WITH ST7FLITE05/09
AN2009
PWM MANAGEMENT FOR 3-PHASE BLDC MOTOR DRIVES USING THE ST7FMC
AN2030
BACK EMF DETECTION DURING PWM ON TIME BY ST7MC
113/117
ST7260
16 KNOWN LIMITATIONS
16.1 PA2 LIMITATION WITH OCMP1 ENABLED
16.3 SCI WRONG BREAK DURATION
Description
This limitation affects only Rev B Flash devices
(with Internal Sales Type 72F60xxxxx$x7); it has
been corrected in Rev W Flash devices (with Internal Sales Type 72F60xxxxx$x9).
Note: Refer to Figure 68 on page 115
When Output Compare 1 function (OCMP1) on pin
PA6 is enabled by setting the OC1E bit in the
TCR2 register, pin PA2 is also affected.
In particular, the PA2 pin is forced to be floating
even if port configuration (PADDR+PADR) has set
it as output low. However, it can be still used as an
input.
Description
A single break character is sent by setting and resetting the SBK bit in the SCICR2 register. In
some cases, the break character may have a longer duration than expected:
- 20 bits instead of 10 bits if M=0
- 22 bits instead of 11 bits if M=1.
In the same way, as long as the SBK bit is set,
break characters are sent to the TDO pin. This
may lead to generate one break more than expected.
Occurrence
The occurrence of the problem is random and proportional to the baudrate. With a transmit frequency of 19200 baud (fCPU=8MHz and SCIBRR=0xC9), the wrong break duration occurrence
is around 1%.
Workaround
If this wrong duration is not compliant with the
communication protocol in the application, software can request that an Idle line be generated
before the break character. In this case, the break
duration is always correct assuming the application is not doing anything between the idle and the
break. This can be ensured by temporarily disabling interrupts.
The exact sequence is:
- Disable interrupts
- Reset and Set TE (IDLE request)
- Set and Reset SBK (Break Request)
- Re-enable interrupts
16.2 UNEXPECTED RESET FETCH
If an interrupt request occurs while a "POP CC" instruction is executed, the interrupt controller does
not recognise the source of the interrupt and, by
default, passes the RESET vector address to the
CPU.
Workaround
To solve this issue, a "POP CC" instruction must
always be preceded by a "SIM" instruction.
16.4 USB Behavior with LVD Disabled
On ROM devices, if the LVD is disabled, the USB
is disabled by hardware. So, the LVD is forced by
ST to 0 (LVD enabled). Refer to the ST7260 option
list for details.
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ST7260
Figure 68. Identifying Silicon Revision from Device Marking and Box Label
The silicon revision can be identified either by Rev letter or obtained via a trace code.
Follow the procedure below:
1. Identify the silicon revision letter from either the device package or the box label.
For example, “B”, etc.
2. If the revision letter is not present, obtain the silicon revision by contacting your local ST
office with the trace code information printed on either the box label or the device package.
Trace code
STMicroelectronics
Silicon Rev
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
TYPE
Total Qty
ST7xxxxxxxxx
xxxxxxxxxxx$x7
XX
Trace code
XXXXXXXXX
Marking
B
XXXXXXXXXXXX
Bulk ID
XX XX
XXXXXXXXXX
Silicon Rev
Device package example
Example box label
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ST7260
17 REVISION HISTORY
Date
Revision
13-Feb-2006
1
Initial release
02-Nov-2006
2
Added Known Limitations section (with new PA2 limitation)
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Main Changes
ST7260
Notes:
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