STMICROELECTRONICS ST62T35B

ST62T35B/E35B
R
8-BIT OTP/EPROM MCUs WITH A/D CONVERTER,
16-BIT AUTO-RELOAD TIMER, EEPROM, SPI AND UART
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3.0 to 6.0V Supply Operating Range
8 MHz Maximum Clock Frequency
-40 to +125°C Operating Temperature Range
Run, Wait and Stop Modes
5 Interrupt Vectors
Look-up Table capability in Program Memory
Data Storage in Program Memory:
User selectable size
Data RAM: 192 bytes
Data EEPROM: 128 bytes
User Programmable Options
36 I/O pins, fully programmable as:
– Input with pull-up resistor
– Input without pull-up resistor
– Input with interrupt generation
– Open-drain or push-pull output
– Analog Input
12 I/O lines can sink up to 20mA to drive LEDs
or TRIACs directly
8-bit Timer/ Counter with 7-bit programmable
prescaler
16-bit
Auto-reload
Timer
with
7-bit
programmable prescaler (AR Timer)
Digital Watchdog
8-bit A/D Converter with 24 analog inputs
8-bit Synchronous Peripheral Interface (SPI)
8-bit Asynchronous Peripheral Interface
(UART)
On-chip Clock oscillator can be driven by Quartz
Crystal or Ceramic resonator
Oscillator Safe Guard
One external Non-Maskable Interrupt
ST623x-EMU2 Emulation and Development
System (connects to an MS-DOS PC via a
parallel port).
PQFP52
CQFP52W
(See end of Datasheet for Ordering Information)
DEVICE SUMMARY
DEVICE
ST62T35B
ST62E35B
OTP
EPROM
(Bytes)
(Bytes)
7948
-
7948
I/O Pins
36
36
Rev. 2.3
March 1998
1/82
1
Table of Contents
ST62T35B/E35B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
1 GENERAL DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
1.1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
1.2 PIN DESCRIPTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
1.3 MEMORY MAP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
1.3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
1.3.2 Program Space . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
1.3.3 Data Space . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
1.3.4 Stack Space . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
1.3.5 Data Window Register (DWR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
1.3.6 Data RAM/EEPROM Bank Register (DRBR). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
1.3.7 EEPROM Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
1.4 PROGRAMMING MODES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
1.4.1 Option Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
1.4.2 Program Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
1.4.3 EEPROM Data Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
1.4.4 EPROM Erasing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
2 CENTRAL PROCESSING UNIT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
2.1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
2.2 CPU REGISTERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
3 CLOCKS, RESET, INTERRUPTS AND POWER SAVING MODES . . . . . . . . . . . . . . . . . . . . . 18
3.1 CLOCK SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
3.1.1 Main Oscillator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
3.1.2 Low Frequency Auxiliary Oscillator (LFAO) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
3.1.3 Oscillator Safe Guard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
3.2 RESETS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
3.2.1 RESET Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
3.2.2 Power-on Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
3.2.3 Watchdog Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
3.2.4 Application Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
3.2.5 MCU Initialization Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
3.3 INTERRUPTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
3.3.1 Interrupt request . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
3.3.2 Interrupt Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
3.3.3 Interrupt Option Register (IOR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
3.3.4 Interrupt sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
3.4 POWER SAVING MODES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30
3.4.1 WAIT Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30
3.4.2 STOP Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30
3.4.3 Exit from WAIT and STOP Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
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4 ON-CHIP PERIPHERALS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32
4.1 I/O PORTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32
4.1.1 Operating Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33
4.1.2 Safe I/O State Switching Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
4.1.3 ARTimer alternate functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
4.1.4 SPI alternate functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
4.1.5 UART alternate functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
4.1.6 I/O Port Option Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
4.1.7 I/O Port Data Direction Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
4.1.8 I/O Port Data Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
4.2 TIMER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39
4.2.1 Timer Operating Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
4.2.2 Timer Interrupt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40
4.2.3 Application Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41
4.2.4 Timer Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41
4.3 ARTIMER 16 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42
4.3.1 CENTRAL COUNTER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
4.3.2 SIGNAL GENERATION MODES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
4.3.3 TIMINGS MEASUREMENT MODES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
4.3.4 INTERRUPT CAPABILITIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
4.3.5 CONTROL REGISTERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
4.3.6 16-BIT REGISTERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .51
4.4 A/D CONVERTER (ADC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
4.4.1 Application Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .53
4.5 U. A. R. T. (UNIVERSAL ASYNCHRONOUS RECEIVER/TRANSMITTER). . . . . . . . . . . 55
4.5.1 PORTS INTERFACING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
4.5.2 CLOCK GENERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
4.5.3 DATA TRANSMISSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
4.5.4 DATA RECEPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57
4.5.5 INTERRUPT CAPABILITIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
4.5.6 REGISTERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57
4.6 SERIAL PERIPHERAL INTERFACE (SPI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
5 SOFTWARE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .61
5.1 ST6 ARCHITECTURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .61
5.2 ADDRESSING MODES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .61
5.3 INSTRUCTION SET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .62
6 ELECTRICAL CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
6.1 ABSOLUTE MAXIMUM RATINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
6.2 RECOMMENDED OPERATING CONDITIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
6.3 DC ELECTRICAL CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
6.4 AC ELECTRICAL CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
6.5 A/D CONVERTER CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
6.6 TIMER CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
6.7 .SPI CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .71
6.8 ARTIMER16 ELECTRICAL CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
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7 GENERAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .72
7.1 PACKAGE MECHANICAL DATA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
7.2 ORDERING INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
ST62P35B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .75
1 GENERAL DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .76
1.1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .76
1.2 ORDERING INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
1.2.1 Transfer of Customer Code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
1.2.2 Listing Generation and Verification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
ST6235B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .79
1 GENERAL DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .80
1.1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .80
1.2 ROM READOUT PROTECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
1.3 ORDERING INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
1.3.1 Transfer of Customer Code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
1.3.2 Listing Generation and Verification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
82
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1
ST62T35B/E35B
1 GENERAL DESCRIPTION
1.1 INTRODUCTION
The ST62T35B and ST62E35B devices are low
cost members of the ST62xx 8-bit HCMOS family
of microcontrollers, which is targeted at low to medium complexity applications. All ST62xx devices
are based on a building block approach: a com-
mon core is surrounded by a number of on-chip
peripherals.
The ST62E35B is the erasable EPROM version of
the ST62T35B device, which may be used to emulate the ST62T35B device, as well as the respective ST6235B ROM devices.
Figure 1. Block Diagram
8-BIT
A/D CONVERTER
TEST/ VPP
NMI
PORT A
PA0..PA1 / 20 mA Sink
PA2/OVF/ 20 mA Sink
PA3/PWM/20 mA Sink
PA4/Ain/CP 1
PA5/Ain/CP2
PA6...PA7/Ain
PORT B
PB0..PB7/Ain
PORT C
PC4..PC7/Ain
PORT D
PD0,PD6,PD7/Ain
PD1/Ain/Scl
PD2/Ain/Si n
PD3/Ain/Sout
PD4/Ain/RXD1
PD5/Ain/TX D1
TEST
INTERRUPT
DATA ROM
USER
SELECTABLE
PROGRAM
Memory
DATA RAM
192 Bytes
79 48 bytes
DATA EEPROM
UART
128 Bytes
PORT E
PE0...PE7
AUTORELOAD
TIMER
PC
STACK LEVEL 1
TIMER
STACK LEVEL 2
STACK LEVEL 3
STACK LEVEL 4
8 BIT CORE
STACK LEVEL 5
STACK LEVEL 6
TIMER
SPI (SERIA L
PERIPHER AL
INTERF ACE)
DIGITAL
WATCHDO G
POWER
SUPPLY
OSCILLATOR
RESET
VDD VSS
OSCin OSCout
RESET
VR01823E
(VPP on EPROM/OTP versions only)
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ST62T35B/E35B
INTRODUCTION (Cont’d)
These compact low-cost devices feature a Timer
comprising an 8-bit counter and a 7-bit programmable prescaler, an 16-bit Auto-Reload Timer,
with 2 input capture channels, EEPROM data capability, a serial synchronous port communication
interface (SPI), a serial asynchronous port interface (UART), an 8-bit A/D Converter with 24 analog inputs and a Digital Watchdog timer, making
them well suited for a wide range of automotive,
appliance and industrial applications.
PE0
PE1
PE2
PE3
PE4
PE5
PE6
PE7
PA0
PA1
PA2/OVF
PA3/PWM
NC
Figure 2. ST62T35B/E35B Pin Configuration
52515049484746454443424140
NC 1
39
OSCin 2
38
OSCout 3
37
Ain/PC7 4
36
35
Ain/PC6 5
34
Ain/PC5 6
33
Ain/PC4 7
32
VSSP 8
VDDP 9
31
VSS 10
30
29
VDD 11
(1)12
28
TEST/VPP
27
RESET 13
14151617181920212223242526
1. V
PP
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5
PA4/Ain/CP 1
PA5/Ain/CP 2
PA6/Ain
PA7/Ain
TIMER
NMI
AVSS
AVDD
PD0/Ain
PD1/Ain/SCL
PD2/Ain/Si n
PD3/Ain/Sout
NC
Ain/PB7
Ain/PB6
Ain/PB5
Ain/PB4
Ain/PB3
Ain/PB2
Ain/PB1
Ain/PB0
Ain/PD7
Ain/PD6
Ain/PD5/TXD1
Ain/PD4/RXD1
NC
OTP and EPROM devices are functionally identical. The ROM based versions offer the same functionality selecting as ROM options the options defined in the programmable option byte of the
OTP/EPROM versions.OTP devices offer all the
advantages of user programmability at low cost,
which make them the ideal choice in a wide range
of applications where frequent code changes,
multiple code versions or last minute programmability are required.
on EPROM/OTP only
VR02008
ST62T35B/E35B
1.2 PIN DESCRIPTIONS
VDD and VSS. Power is supplied to the MCU via
these two pins. VDD is the power connection and
VSS is the ground connection.
In addition, PA4-PA5 can also be used as analog
inputs for the A/D converter while PA0-PA3 can
sink 20mA for direct LED or TRIAC drive.
VDDp and VSSp. Power is supplied to the MCU
I/Os independently from the rest of the chip using
these two pins. These pins have to be connected
to the VDD and VSS pins. It is not allowed to leave
any of these pins unconnected or to apply different
potentials respectively to VDD/VDDp and
VSS/VSSp.
PB0...PB7 These 8 lines are organised as one I/O
port (B). Each line may be configured under software control as inputs with or without internal pullup resistors, interrupt generating inputs with pullup resistors, open-drain or push-pull outputs, analog inputs for the A/D converter.
AVDD and AVSS. Power is supplied to the
MCUA/D converter independently from the rest of
the chip using these two pins.
OSCin and OSCout. These pins are internally
connected to the on-chip oscillator circuit. A quartz
crystal, a ceramic resonator or an external clock
signal can be connected between these two pins.
The OSCin pin is the input pin, the OSCout pin is
the output pin.
RESET. The active-low RESET pin is used to restart the microcontroller.
TEST/VPP. The TEST must be held at VSS for normal operation. If TEST pin is connected to a
+12.5V level during the reset phase, the
EPROM/OTP programming Mode is entered.
NMI. The NMI pin provides the capability for asynchronous interruption, by applying an external non
maskable interrupt to the MCU. The NMI input is
falling edge sensitive with Schmitt trigger characteristics. The user can select as option the availability of an on-chip pull-up at this pin.
PA0-PA7. These 8 lines are organised as one I/O
port (A). Each line may be configured under software control as inputs with or without internal pullup resistors, interrupt generating inputs with pullup resistors, open-drain or push-pull outputs.
PA2/OVF, PA3/PWM, PA4/CP1 and PA5/CP2
can be used respectively as overflow output pin,
output compare pin, and as two input capture pins
for the embedded 16-bit Auto-Reload Timer.
PC4-PC7. These 4 lines are organised as one I/O
port (C). Each line may be configured under software control as input with or without internal pullup resistor, interrupt generating input with pull-up
resistor, analog input for the A/D converter, opendrain or push-pull output.
PD0...PD7. These 8 lines are organised as one
I/O port (portD). Each line may be configured
under software control as input with or without internal pull-up resistor, interrupt generating input
with pull-up resistor, analog input open-drain or
push-pull output. In adition, the pins PD5/TXD1
and PD4/RXD1 can be used as UART output
(PD5/TXD1) or UART input (PD4/RXD1). The pins
PD3/Sout, PD2/Sin and PD1/SCL can also be
used respectively as data out, data in and Clock
pins for the on-chip SPI.
PE0...PE7. These 8 lines are organised as one I/O
port (PE). Each line may be configured under software control as input with or without internal pullup resistor, interrupt generation input with pull-up
resistor, open-drain or push-pull output. In output
mode, these lines can also sink 20mA for direct
LED and TRIAC driving.
TIMER. This is the TIMER 1 I/O pin. In input
mode, it is connected to the prescaler and acts as
external timer clock or as control gate for the internal timer clock. In output mode, the TIMER pin
outputs the data bit when a time-out occurs.The
user can select as option the availability of an onchip pull-up at this pin.
7/82
6
ST62T35B/E35B
1.3 MEMORY MAP
1.3.1 Introduction
The MCU operates in three separate memory
spaces: Program space, Data space, and Stack
space. Operation in these three memory spaces is
described in the following paragraphs.
Briefly, Program space contains user program
code in Program memory and user vectors; Data
space contains user data in RAM and in Program
memory, and Stack space accommodates six levels of stack for subroutine and interrupt service
routine nesting.
1.3.2 Program Space
Program Space comprises the instructions to be
executed, the data required for immediate addressing mode instructions, the reserved factory
test area and the user vectors. Program Space is
addressed via the 12-bit Program Counter register
(PC register).
common (STATIC) 2K page is available all the
time for interrupt vectors and common subroutines, independently of the PRPR register content.
This “STATIC” page is directly addressed in the
0800h-0FFFh by the MSB of the Program Counter
register PC 11. Note this page can also be addressed in the 000-7FFh range. It is two different
ways of addressing the same physical memory.
Jump from a dynamic page to another dynamic
page is achieved by jumping back to the static
page, changing contents of PRPR and then jumping to the new dynamic page.
Figure 3. 8Kbytes Program Space Addressing
ROM SPACE
PC
SPACE
1FFFh
0000h
000h
Page 1
Static
Page
Page 0
Program Space is organised in four 2K pages.
Three of them are addressed in the 000h-7FFh locations of the Program Space by the Program
Counter and by writing the appropriate code in the
Program ROM Page Register (PRPR register). A
7FFh
800h
FFFh
Page 2
Page 3
Page 1
Static
Page
Figure 4. Memory Addressing Diagram
PROGRAM SPACE
DATA SPACE
0000h
000h
RAM / EEPROM
BANKING AREA
0-63
PROGRAM
MEMORY
03Fh
040h
DATA READ-ONLY
MEMORY WINDOW
07Fh
080h
081h
082h
083h
084h
RAM
0C0h
DATA READ-ONLY
MEMORY
WINDOW SELECT
DATA RAM
BANK SELECT
0FFh
ACCUMULATOR
0FF0h
INTERRUPT &
RESET VECTORS
0FFFh
X REGISTER
Y REGISTER
V REGISTER
W REGISTER
VR01568
8/82
7
ST62T35B/E35B
MEMORY MAP (Cont’d)
Table 1. ST62E35B/T35B Program Memory Map
ROM Page
Device Address
Description
Page 0
0000h-007Fh
0080h-07FFh
Reserved
User ROM
Page 1
“STATIC”
0800h-0F9Fh
0FA0h-0FEFh
0FF0h-0FF7h
0FF8h-0FFBh
0FFCh-0FFDh
0FFEh-0FFFh
User ROM
Reserved
Interrupt Vectors
Reserved
NMI Vector
Reset Vector
Page 2
0000h-000Fh
0010h-07FFh
Reserved
User ROM
Page 3
0000h-000Fh
0010h-07FFh
Reserved
User ROM
Note: OTP/EPROM devices can be programmed
with the development tools available from
SGS-THOMSON (ST62E3X-EPB or ST623X-KIT).
1.3.2.1 Program ROM Page Register (PRPR)
The PRPR register can be addressed like a RAM
location in the Data Space at the address CAh ;
nevertheless it is a write only register that cannot
be accessed with single-bit operations. This register is used to select the 2-Kbyte ROM bank of the
Program Space that will be addressed. The
number of the page has to be loaded in the PRPR
register. Refer to the Program Space description
for additional information concerning the use of
this register. The PRPR register is not modified
when an interrupt or a subroutine occurs.
Care is required when handling the PRPR register
as it is write only. For this reason, it is not allowed
to change the PRPR contents while executing interrupt service routine, as the service routine
cannot save and then restore its previous content.
This operation may be necessary if common routines and interrupt service routines take more than
2K bytes ; in this case it could be necessary to divide the interrupt service routine into a (minor) part
in the static page (start and end) and to a second
(major) part in one of the dynamic pages. If it is impossible to avoid the writing of this register in interrupt service routines, an image of this register
must be saved in a RAM location, and each time
the program writes to the PRPR it must write also
to the image register. The image register must be
written before PRPR, so if an interrpt occurs between the two instructions the PRPR is not affected.
Program ROM Page Register (PRPR)
Address: CAh —
Write Only
7
0
-
-
-
-
-
-
PRPR0 PRPR1
Bits 2-7= Not used.
Bit 5-0 = PRPR1-PRPR0: Program ROM Select.
These two bits select the corresponding page to
be addressed in the lower part of the 4K program
address space as specified inTable 2.
This register is undefined on Reset. Neither read
nor single bit instructions may be used to address
this register.
Table 2. 8Kbytes Program ROM Page Register
Coding
PRPR1
PRPR0
PC bit 11
Memory Page
X
X
1
Static Page (Page 1)
0
0
0
Page 0
0
1
0
Page 1 (Static Page
1
0
0
Page 2
1
1
0
Page 3
1.3.2.2 Program Memory Protection
The Program Memory in OTP or EPROM devices
can be protected against external readout of
memory by selecting the READOUT PROTECTION option in the option byte.
In the EPROM parts, READOUT PROTECTION
option can be disactivated only by U.V. erasure
that also results into the whole EPROM context
erasure.
Note: Once the Readout Protection is activated, it
is no longer possible, even for SGS-THOMSON,
to gain access to the Program memory contents.
Returned parts with a protection set can therefore
not be accepted.
9/82
8
ST62T35B/E35B
MEMORY MAP (Cont’d)
1.3.3 Data Space
Table 4. ST62T35B Data Memory Space
Data Space accommodates all the data necessary
for processing the user program. This space comprises the RAM resource, the processor core and
peripheral registers, as well as read-only data
such as constants and look-up tables in Program
memory.
1.3.3.1 Data ROM
All read-only data is physically stored in program
memory, which also accommodates the Program
Space. The program memory consequently contains the program code to be executed, as well as
the constants and look-up tables required by the
application.
The Data Space locations in which the different
constants and look-up tables are addressed by
the processor core may be thought of as a 64-byte
window through which it is possible to access the
read-only data stored in Program memory.
1.3.3.2 Data RAM/EEPROM
In ST6235B and ST62E35B devices, the data
space includes 60 bytes of RAM, the accumulator
(A), the indirect registers (X), (Y), the short direct
registers (V), (W), the I/O port registers, the peripheral data and control registers, the interrupt
option register and the Data ROM Window register (DRW register).
Additional RAM and EEPROM pages can also be
addressed using banks of 64 bytes located between addresses 00ST62T35B and ST62E35Bh
and 3Fh.
1.3.4 Stack Space
Stack space consists of six 12-bit registers which
are used to stack subroutine and interrupt return
addresses, as well as the current program counter
contents.
Table 3. Additional RAM/EEPROM Banks.
Device
ST62T35B
10/82
9
000h
03Fh
040h
DATA ROM WINDOW AREA
07Fh
X REGISTER
080h
Y REGISTER
081h
V REGISTER
082h
W REGISTER
083h
084h
DATA RAM
0BFh
PORT A DATA REGISTER
0C0h
PORT B DATA REGISTER
0C1h
PORT C DATA REGISTER
0C2h
PORT D DATA REGISTER
0C3h
PORT A DIRECTION REGISTER
0C4h
PORT B DIRECTION REGISTER
0C5h
PORT C DIRECTION REGISTER
0C6h
PORT D DIRECTION REGISTER
0C7h
INTERRUPT OPTION REGISTER
0C8h*
DATA ROM WINDOW REGISTER
0C9h*
ROM BANK SELECT REGISTER
0CAh*
RAM/EEPROM BANK SELECT REGISTER
0CBh*
PORT A OPTION REGISTER
0CCh
PORT B OPTION REGISTER
0CDh
PORT C OPTION REGISTER
0CEh
PORT D OPTION REGISTER
0CFh
A/D DATA REGISTER
0D0h
A/D CONTROL REGISTER
0D1h
TIMER 1 PRESC ALER REGISTER
0D2h
TIMER 1 COUNTER REGISTER
0D3h
TIMER 1 STATUS/CONTROL REGISTER
0D4h
RESERVED
0D5h
UART DATA SHIFT REGISTE R
0D6h
UART STATUS CONTROL REGIST ER
0D7h
WATCHDOG REGISTER
0D8h
RESERVED
0D9h
I/O INTE RRUPT POLARITY REGISTER
0DAh
OSCILLATOR CONTROL REGISTER
0DBh
SPI INTERRUPT DISABLE REGISTER
0DCh*
SPI DATA REGISTER
0DDh
RESERVED
0DEh
EEPROM CONTROL REGISTER
0DFh
ARTIM16 COMPARE MASK REG. LOW BYTE MASK
0E0h
ARTIM16 2ND STATUS CONTROL REGISTER SCR2
0E1h
ARTIM16 3RD STATUS CONTROL REGISTER SCR3
0E2h
ARTIM16 4TH STATUS CONTROL REGISTER SCR4
0E3h
ARTIM16 1ST STATUS CONTROL REGISTER SCR1
0E8h
ARTIM16 RELOAD CAPTUR E REG. HIGH BYTE RLCP 0E9h
ARTIM16 RELOAD CAPTURE REG. LOW BYTE RLCP 0EAh
ARTIM16 CAPT URE REGISTER HIGH BYTE CP
0EBh
ARTIM16 CAPTURE REGISTER LOW BYTE CP
0ECh
ARTIM16COMPAREVALUE REGISTE RHIGH BYTE CMP 0EDh
ARTIM 16 COMPARE VALUE REGISTER LOWBYTE CMP 0EEh
ARTIM 16 COMPARE MASK REG. HIGH BYTE MASK 0EFh
RESERVED
0F0h
0FBh
PORT E DATA REGISTER
OFCh
PORT E DIRECTION REGISTER
0FDh
PORT E OPTION REGISTE R
0FEh
ACCUMULATOR
OFFh
* WRITE ONLY REGISTER
DATA and EEPROM
RAM
EEPROM
2 x 64 bytes
2 x 64 bytes
ST62T35B/E35B
MEMORY MAP (Cont’d)
1.3.5 Data Window Register (DWR)
Data Window Register (DWR)
The Data read-only memory window is located
from address 0040h to address 007Fh in Data
space. It allows direct reading of 64 consecutive
bytes located anywhere in program memory, between address 0000h and 1FFFh (top memory address depends on the specific device). All the program memory can therefore be used to store either
instructions or read-only data. Indeed, the window
can be moved in steps of 64 bytes along the program memory by writing the appropriate code in the
Data Window Register (DWR).
The DWR can be addressed like any RAM location in the Data Space, it is however a write-only
register and therefore cannot be accessed using
single-bit operations. This register is used to position the 64-byte read-only data window (from address 40h to address 7Fh of the Data space) in
program memory in 64-byte steps. The effective
address of the byte to be read as data in program
memory is obtained by concatenating the 6 least
significant bits of the register address given in the
instruction (as least significant bits) and the content of the DWR register (as most significant bits),
as illustrated in Figure 5 below. For instance,
when addressing location 0040h of the Data
Space, with 0 loaded in the DWR register, the
physical location addressed in program memory is
00h. The DWR register is not cleared on reset,
therefore it must be written to prior to the first access to the Data read-only memory window area.
Address: 0C9h —
Write Only
7
0
-
DWR6 DWR5 DWR4 DWR3 DWR2 DWR1 DWR0
Bits 7 = Not used.
Bit 6-0 = DWR5-DWR0: Data read-only memory
Window Register Bits. These are the Data readonly memory Window bits that correspond to the
upper bits of the data read-only memory space.
Caution: This register is undefined on reset. Neither read nor single bit instructions may be used to
address this register.
Note: Care is required when handling the DWR
register as it is write only. For this reason, the
DWR contents should not be changed while executing an interrupt service routine, as the service
routine cannot save and then restore the register’s
previous contents. If it is impossible to avoid writing to the DWR during the interrupt service routine, an image of the register must be saved in a
RAM location, and each time the program writes
to the DWR, it must also write to the image register. The image register must be written first so
that, if an interrupt occurs between the two instructions, the DWR is not affected.
Figure 5. Data read-only memory Window Memory Addressing
DATA ROM
13
WINDOW REGISTER 7
CONTENTS
12
11
10
9
8
7
6
6
5
4
3
2
1
0
(DWR)
5
4
3
2
1
0 PROGRAM SPACE ADDRESS
READ
5
4
3
2
1
0
0
1
0
0
0
1
0
1
1
0
0
1
0
0
0
1
1
0
0
1
DATA SPACE ADDRESS
40h-7Fh
IN INSTRUCTION
Example:
DWR=28h
ROM
ADDRESS:A19h
0
0
1
1
0
0
1
1
0
0
DATA SPACE ADDRESS
59h
VR0A1573
11/82
10
ST62T35B/E35B
MEMORY MAP (Cont’d)
1.3.6 Data RAM/EEPROM
(DRBR)
Address: CBh —
Bank
Register
Write only
7
-
0
-
-
DRBR4 DRBR3
-
DRBR1 DRBR0
has to point to the selected location as if it was in
bank 0 (from 00h address to 3Fh address).
This register is not cleared during the MCU initialization, therefore it must be written before the first
access to the Data Space bank region. Refer to
the Data Space description for additional information. The DRBR register is not modified when an
interrupt or a subroutine occurs.
Bit 7-5 = These bits are not used
Notes :
Bit 4 - DRBR4. This bit, when set, selects RAM
Page 2.
Care is required when handling the DRBR register
as it is write only. For this reason, it is not allowed
to change the DRBR contents while executing interrupt service routine, as the service routine cannot save and then restore its previous content. If it
is impossible to avoid the writing of this register in
interrupt service routine, an image of this register
must be saved in a RAM location, and each time
the program writes to DRBR it must write also to
the image register. The image register must be
written first, so if an interrupt occurs between the
two instructions the DRBR is not affected.
Bit 3 - DRBR3. This bit, when set, selects RAM
Page 1.
Bit2. This bit is not used.
Bit 1 - DRBR1. This bit, when set, selects
EEPROM Page 1.
Bit 0 - DRBR0. This bit, when set, selects
EEPROM Page 0.
The selection of the bank is made by programming the Data RAM Bank Switch register (DRBR
register) located at address CBh of the Data
Space according to Table 1. No more than one
bank should be set at a time.
The DRBR register can be addressed like a RAM
Data Space at the address CBh; nevertheless it is
a write only register that cannot be accessed with
single-bit operations. This register is used to select the desired 64-byte RAM/EEPROM bank of
the Data Space. The number of banks has to be
loaded in the DRBR register and the instruction
12/82
11
In DRBR Register, only 1 bit must be set. Otherwise two or more pages are enabled in parallel,
producing errors.
Table 5. Data RAM Bank Register Set-up
DRBR
ST62T35B
00
None
01
EEPROM Page 0
02
EEPROM Page 1
08
RAM Page 1
10h
RAM Page 2
other
Reserved
ST62T35B/E35B
MEMORY MAP (Cont’d)
1.3.7 EEPROM Description
EEPROM memory is located in 64-byte pages in
data space. This memory may be used by the user
program for non-volatile data storage.
Data space from 00h to 3Fh is paged as described
in Table 6 . EEPROM locations are accessed directly by addressing these paged sections of data
space.
The EEPROM does not require dedicated instructions for read or write access. Once selected via the
Data RAM Bank Register, the active EEPROM
page is controlled by the EEPROM Control Register (EECTL), which is described below.
Bit E20FF of the EECTL register must be reset prior
to any write or read access to the EEPROM. If no
bank has been selected, or if E2OFF is set, any access is meaningless.
Programming must be enabled by setting the
E2ENA bit of the EECTL register.
The E2BUSY bit of the EECTL register is set when
the EEPROM is performing a programming cycle.
Any access to the EEPROM when E2BUSY is set
is meaningless.
Provided E2OFF and E2BUSY are reset, an EEPROM location is read just like any other data location, also in terms of access time.
Writing to the EEPROM may be carried out in two
modes: Byte Mode (BMODE) and Parallel Mode
(PMODE). In BMODE, one byte is accessed at a
time, while in PMODE up to 8 bytes in the same
row are programmed simultaneously (with consequent speed and power consumption advantages,
the latter being particularly important in battery
powered circuits).
General Notes:
Data should be written directly to the intended address in EEPROM space. There is no buffer memory between data RAM and the EEPROM space.
When the EEPROM is busy (E2BUSY = “1”)
EECTL cannot be accessed in write mode, it is
only possible to read the status of E2BUSY. This
implies that as long as the EEPROM is busy, it is
not possible to change the status of the EEPROM
Control Register. EECTL bits 4 and 5 are reserved
and must never be set.
Care is required when dealing with the EECTL register, as some bits are write only. For this reason,
the EECTL contents must not be altered while executing an interrupt service routine.
If it is impossible to avoid writing to this register
within an interrupt service routine, an image of the
register must be saved in a RAM location, and
each time the program writes to EECTL it must
also write to the image register. The image register must be written to first so that, if an interrupt occurs between the two instructions, the EECTL will
not be affected.
Table 6. Row Arrangement for Parallel Writing of EEPROM Locations
Dataspace
addresses.
Banks 0 and 1.
Byte
ROW7
ROW6
ROW5
ROW4
ROW3
ROW2
ROW1
ROW0
0
1
2
3
4
5
6
7
38h-3Fh
30h-37h
28h-2Fh
20h-27h
18h-1Fh
10h-17h
08h-0Fh
00h-07h
Up to 8 bytes in each row may be programmed simultaneously in Parallel Write mode.
The number of available 64-byte banks (1 or 2) is device dependent.
13/82
12
ST62T35B/E35B
MEMORY MAP (Cont’d)
Additional Notes on Parallel Mode:
EEPROM Control Register (EECTL)
If the user wishes to perform parallel programming, the first step should be to set the E2PAR2
bit. From this time on, the EEPROM will be addressed in write mode, the ROW address will be
latched and it will be possible to change it only at
the end of the programming cycle, or by resetting
E2PAR2 without programming the EEPROM. After the ROW address is latched, the MCU can only
“see” the selected EEPROM row and any attempt
to write or read other rows will produce errors.
Address: DFh — Read/Write
The EEPROM should not be read while E2PAR2
is set.
As soon as the E2PAR2 bit is set, the 8 volatile
ROW latches are cleared. From this moment on,
the user can load data in all or in part of the ROW.
Setting E2PAR1 will modify the EEPROM registers corresponding to the ROW latches accessed
after E2PAR2. For example, if the software sets
E2PAR2 and accesses the EEPROM by writing to
addresses 18h, 1Ah and 1Bh, and then sets
E2PAR1, these three registers will be modified simultaneously; the remaining bytes in the row will
be unaffected.
Note that E2PAR2 is internally reset at the end of
the programming cycle. This implies that the user
must set the E2PAR2 bit between two parallel programming cycles. Note that if the user tries to set
E2PAR1 while E2PAR2 is not set, there will be no
programming cycle and the E2PAR1 bit will be unaffected. Consequently, the E2PAR1 bit cannot be
set if E2ENA is low. The E2PAR1 bit can be set by
the user, only if the E2ENA and E2PAR2 bits are
also set.
Reset status: 00h
7
D7 E2OFF
0
D5
D4
E2PAR1 E2PAR2 E2BUSY E2ENA
Bit 7 = D7: Unused.
Bit 6 = E2OFF: Stand-by Enable Bit.WRITE ONLY.
If this bit is set the EEPROM is disabled (any access
will be meaningless) and the power consumption of
the EEPROM is reduced to its lowest value.
Bit 5-4 = D5-D4: Reserved. MUST be kept reset.
Bit 3 = E2PAR1: Parallel Start Bit. WRITE ONLY.
Once in Parallel Mode, as soon as the user software
sets the E2PAR1 bit, parallel writing of the 8 adjacent registers will start. This bit is internally reset at
the end of the programming procedure. Note that
less than 8 bytes can be written if required, the undefined bytes being unaffected by the parallel programming cycle; this is explained in greater detail
in the Additional Notes on Parallel Mode overleaf.
Bit 2 = E2PAR2: Parallel Mode En. Bit. WRITE
ONLY. This bit must be set by the user program in
order to perform parallel programming. If E2PAR2
is set and the parallel start bit (E2PAR1) is reset,
up to 8 adjacent bytes can be written simultaneously. These 8 adjacent bytes are considered as a
row, whose address lines A7, A6, A5, A4, A3 are
fixed while A2, A1 and A0 are the changing bits,
as illustrated in Table 6. E2PAR2 is automatically
reset at the end of any parallel programming procedure. It can be reset by the user software before
starting the programming procedure, thus leaving
the EEPROM registers unchanged.
Bit 1 = E2BUSY: EEPROM Busy Bit. READ ONLY. This bit is automatically set by the EEPROM
control logic when the EEPROM is in programming mode. The user program should test it before any EEPROM read or write operation; any attempt to access the EEPROM while the busy bit is
set will be aborted and the writing procedure in
progress will be completed.
Bit 0 = E2ENA: EEPROM Enable Bit. WRITE ONLY. This bit enables programming of the EEPROM
cells. It must be set before any write to the EEPROM register. Any attempt to write to the EEPROM when E2ENA is low is meaningless and will
not trigger a write cycle.
14/82
13
ST62T35B/E35B
1.4 PROGRAMMING MODES
1.4.1 Option Byte
The Option Byte allows configuration capability to
the MCUs. Option byte’s content is automatically
read, and the selected options enabled, when the
chip reset is activated.
It can only be accessed during the programming
mode. This access is made either automatically
(copy from a master device) or by selecting the
OPTION BYTE PROGRAMMING mode of the
programmer.
The option byte is located in a non-user map. No
address has to be specified.
EPROM Code Option Byte
7
-
0
PORT
TIM NMI
EXTC NTL PROTECT
WDACT OSGEN
PULL
PULL PULL
Bit 7. Reserved.
Bit 6 = PORT PULL. This bit must be set high to
have pull-up input state at reset on the I/O port.
When this bit is low, I/O ports are in input without
pull-up (high impedance) state at reset
Bit 5 = EXTCNTL. This bit selects the External
STOP Mode capability. When EXTCNTL is high,
pin NMI controls if the STOP mode can be accessed when the watchdog is active. When
EXTCNTL is low, the STOP instruction is processed as a WAIT as soon as the watchdog is active.
Bit 4 = PROTECT. This bit allows the protection of
the software contents against piracy. When the bit
PROTECT is set high, readout of the OTP contents is prevented by hardware. No programming
equipment is able to gain access to the user program. When this bit is low, the user program can
be read.
Bit 3 = TIM PULL. This bit must be set high to configure the TIMER pin with a pull up resistor. When
it is low, no pull up is provided.
Bit 2 = NMI PULL. This bit must be set high to configure the NMI pin with a pull up resistor when it is
low, no pull up is provided.
Bit 1 = WDACT. This bit controls the watchdog activation. When it is high, hardware activation is selected. The software activation is selected when
WDACT is low.
Bit 0 = OSGEN. This bit must be set high to enable
the oscillator Safe Guard. When this bit is low, the
OSG is disabled.
The Option byte is written during programming either by using the PC menu (PC driven Mode) or
automatically (stand-alone mode)
1.4.2 Program Memory
EPROM/OTP programming mode is set by a
+12.5V voltage applied to the TEST/VPP pin. The
programming flow of the ST62T35B is described
in the User Manual of the EPROM Programming
Board.
The MCUs can be programmed with the
ST62E3xB EPROM programming tools available
from SGS-THOMSON.
1.4.3 EEPROM Data Memory
EEPROM data pages are supplied in the virgin
state FFh. Partial or total programming of EEPROM data memory can be performed either
through the application software, or through an external programmer. Any SGS-THOMSON tool
used for the program memory (OTP/EPROM) can
also be used to program the EEPROM data memory.
1.4.4 EPROM Erasing
The EPROM of the windowed package of the
MCUs may be erased by exposure to Ultra Violet
light. The erasure characteristic of the MCUs is
such that erasure begins when the memory is exposed to light with a wave lengths shorter than approximately 4000Å. It should be noted that sunlights and some types of fluorescent lamps have
wavelengths in the range 3000-4000Å.
It is thus recommended that the window of the
MCUs packages be covered by an opaque label to
prevent unintentional erasure problems when testing the application in such an environment.
The recommended erasure procedure of the
MCUs EPROM is the exposure to short wave ultraviolet light which have a wave-length 2537A.
The integrated dose (i.e. U.V. intensity x exposure
time) for erasure should be a minimum of 15Wsec/cm2. The erasure time with this dosage is approximately 15 to 20 minutes using an ultraviolet
lamp with 12000µW/cm2 power rating. The
ST62E35B should be placed within 2.5cm (1Inch)
of the lamp tubes during erasure.
15/82
14
ST62T35B/E35B
2 CENTRAL PROCESSING UNIT
2.1 INTRODUCTION
The CPU Core of ST6 devices is independent of
the I/O or Memory configuration. As such, it may be
thought of as an independent central processor
communicating with on-chip I/O, Memory and Peripherals via internal address, data, and control
buses. In-core communication is arranged as
shown in Figure 6; the controller being externally
linked to both the Reset and Oscillator circuits,
while the core is linked to the dedicated on-chip peripherals via the serial data bus and indirectly, for
interrupt purposes, through the control registers.
Indirect Registers (X, Y). These two indirect registers are used as pointers to memory locations in
Data space. They are used in the register-indirect
addressing mode. These registers can be addressed in the data space as RAM locations at addresses 80h (X) and 81h (Y). They can also be accessed with the direct, short direct, or bit direct addressing modes. Accordingly, the ST6 instruction
set can use the indirect registers as any other register of the data space.
Short Direct Registers (V, W). These two registers are used to save a byte in short direct addressing mode. They can be addressed in Data
space as RAM locations at addresses 82h (V) and
83h (W). They can also be accessed using the direct and bit direct addressing modes. Thus, the
ST6 instruction set can use the short direct registers as any other register of the data space.
2.2 CPU REGISTERS
The ST6 Family CPU core features six registers and
three pairs of flags available to the programmer.
These are described in the following paragraphs.
Accumulator (A). The accumulator is an 8-bit
general purpose register used in all arithmetic calculations, logical operations, and data manipulations. The accumulator can be addressed in Data
space as a RAM location at address FFh. Thus
the ST6 can manipulate the accumulator just like
any other register in Data space.
Program Counter (PC). The program counter is a
12-bit register which contains the address of the
next ROM location to be processed by the core.
This ROM location may be an opcode, an operand, or the address of an operand. The 12-bit
length allows the direct addressing of 4096 bytes
in Program space.
Figure 6ST6 Core Block Diagram
0,01 TO 8MHz
RESET
OSCin
OSCout
INTERRUP TS
CONTROLLER
DATA SPACE
OPCODE
FLAG
VALUES
CONTROL
SIGNALS
DATA
ADDRESS/READ LINE
2
RAM/EE PROM
PROGRAM
ADDRESS 256
DECODER
ROM/EPROM
A-DATA
B-DATA
DATA
ROM/EPROM
DEDICATION S
ACCUMULATOR
12
Program Counter
and
6 LAYER STACK
FLAGS
ALU
RESULTS TO DATA SPACE (WRITE LINE)
VR01811
16/82
15
ST62T35B/E35B
CPU REGISTERS (Cont’d)
However, if the program space contains more
than 4096 bytes, the additional memory in program space can be addressed by using the Program Bank Switch register.
The PC value is incremented after reading the address of the current instruction. To execute relative jumps, the PC and the offset are shifted
through the ALU, where they are added; the result
is then shifted back into the PC. The program
counter can be changed in the following ways:
- JP (Jump) instructionPC=Jump address
- CALL instructionPC= Call address
- Relative Branch Instruction.PC= PC +/- offset
- Interrupt PC=Interrupt vector
- ResetPC= Reset vector
- RET & RETI instructionsPC= Pop (stack)
- Normal instructionPC= PC + 1
Flags (C, Z). The ST6 CPU includes three pairs of
flags (Carry and Zero), each pair being associated
with one of the three normal modes of operation:
Normal mode, Interrupt mode and Non Maskable
Interrupt mode. Each pair consists of a CARRY
flag and a ZERO flag. One pair (CN, ZN) is used
during Normal operation, another pair is used during Interrupt mode (CI, ZI), and a third pair is used
in the Non Maskable Interrupt mode (CNMI, ZNMI).
The ST6 CPU uses the pair of flags associated
with the current mode: as soon as an interrupt (or
a Non Maskable Interrupt) is generated, the ST6
CPU uses the Interrupt flags (resp. the NMI flags)
instead of the Normal flags. When the RETI instruction is executed, the previously used set of
flags is restored. It should be noted that each flag
set can only be addressed in its own context (Non
Maskable Interrupt, Normal Interrupt or Main routine). The flags are not cleared during context
switching and thus retain their status.
The Carry flag is set when a carry or a borrow occurs during arithmetic operations; otherwise it is
cleared. The Carry flag is also set to the value of
the bit tested in a bit test instruction; it also participates in the rotate left instruction.
The Zero flag is set if the result of the last arithmetic or logical operation was equal to zero; otherwise it is cleared.
Switching between the three sets of flags is performed automatically when an NMI, an interrupt or
a RETI instructions occurs. As the NMI mode is
automatically selected after the reset of the MCU,
the ST6 core uses at first the NMI flags.
Stack. The ST6 CPU includes a true LIFO hardware stack which eliminates the need for a stack
pointer. The stack consists of six separate 12-bit
RAM locations that do not belong to the data
space RAM area. When a subroutine call (or interrupt request) occurs, the contents of each level
are shifted into the next higher level, while the
content of the PC is shifted into the first level (the
original contents of the sixth stack level are lost).
When a subroutine or interrupt return occurs (RET
or RETI instructions), the first level register is shifted back into the PC and the value of each level is
popped back into the previous level. Since the accumulator, in common with all other data space
registers, is not stored in this stack, management
of these registers should be performed within the
subroutine. The stack will remain in its “deepest”
position if more than 6 nested calls or interrupts
are executed, and consequently the last return address will be lost. It will also remain in its highest
position if the stack is empty and a RET or RETI is
executed. In this case the next instruction will be
executed.
Figure 7ST6 CPU Programming Mode
l
INDEX
REGISTER
b11
b7
X REG. POINTER
b0
b7
Y REG. POINTER
b0
SHORT
DIRECT
ADDRESSING
MODE
b0
b7
V REGISTER
b7
W REGISTER
b0
b7
AC CUMUL ATOR
b0
PROGRAM COUNTER
b0
SIX LEVELS
STACK REGISTER
NORMAL FLAGS
C
Z
INTERRUPT FLAGS
C
Z
NMI FLAGS
C
Z
VA000423
17/82
16
ST62T35B/E35B
3 CLOCKS, RESET, INTERRUPTS AND POWER SAVING MODES
3.1 CLOCK SYSTEM
The MCU features a Main Oscillator which can be
driven by an external clock, or used in conjunction
with an AT-cut parallel resonant crystal or a suitable ceramic resonator. In addition, a Low Frequency Auxiliary Oscillator (LFAO) can be switched in
for security reasons, to reduce power consumption, or to offer the benefits of a back-up clock system.
The Oscillator Safeguard (OSG) option filters
spikes from the oscillator lines, provides access to
the LFAO to provide a backup oscillator in the
event of main oscillator failure and also automatically limits the internal clock frequency (fINT) as a
function of VDD, in order to guarantee correct operation. These functions are illustrated in Figure
9., Figure 10., Figure 11. and Figure 12..
Figure 8. illustrates various possible oscillator configurations using an external crystal or ceramic resonator, an external clock input or the lowest cost solution using only the LFAO. CL1 an CL2 should have
a capacitance in the range 12 to 22 pF for an oscillator frequency in the 4-8 MHz range.
The internal MCU clock frequency (fINT) is divided
by 12 to drive the Timer and the Watchdog timer,
and by 13 to drive the CPU core, while the A/D
converter is driven by fINT divided either by 6 or by
12 as may be seen inFigure 11..
With an 8MHz oscillator frequency, the fastest
machine cycle is therefore 1.625µs.
A machine cycle is the smallest unit of time needed
to execute any operation (for instance, to increment
the Program Counter). An instruction may require
two, four, or five machine cycles for execution.
3.1.1 Main Oscillator
The main oscillator can be turned off (when the
OSG ENABLED option is selected) by setting the
OSCOFF bit of the OSCR Control Register. The
Low Frequency Auxiliary Oscillator is automatically started.
18/82
17
Figure 8. Oscillator Configurations
CRYSTAL/RESON ATOR CLOCK
ST6xxx
OSCin
OSCout
CL1n
CL2
VA0016
EXTER NAL CLOCK
ST6xxx
OSCin
OSCout
NC
VA0015A
INTEGR ATED CLOCK
OSG ENABLED option
ST6xxx
OSCin
OSCout
NC
ST62T35B/E35B
CLOCK SYSTEM (Cont’d)
Turning on the main oscillator is achieved by resetting the OSCOFF bit of the OSCR Register or
by resetting the MCU. Restarting the main oscillator implies a delay comprising the oscillator start
up delay period plus the duration of the software
instruction at fLFAO clock frequency.
3.1.2 Low Frequency Auxiliary Oscillator
(LFAO)
The Low Frequency Auxiliary Oscillator has three
main purposes. Firstly, it can be used to reduce
power consumption in non timing critical routines.
Secondly, it offers a fully integrated system clock,
without any external components. Lastly, it acts as
a safety oscillator in case of main oscillator failure.
This oscillator is available when the OSG ENABLED option is selected. In this case, it automatically starts one of its periods after the first missing
edge from the main oscillator, whatever the reason (main oscillator defective, no clock circuitry
provided, main oscillator switched off...).
User code, normal interrupts, WAIT and STOP instructions, are processed as normal, at the reduced fLFAO frequency. The A/D converter accuracy is decreased, since the internal frequency is
below 1MHz.
At power on, the Low Frequency Auxiliary Oscillator starts faster than the Main Oscillator. It therefore feeds the on-chip counter generating the
POR delay until the Main Oscillator runs.
The Low Frequency Auxiliary Oscillator is automatically switched off as soon as the main oscillator starts.
OSCR
Address: 0DBh — Read/Write
7
-
0
-
-
-
-
-
-
OSC
OFF
Bit 7-1= These bits are not used and must be kept
cleared after reset.
Bit 0 = OSCOFF. Main oscillator turn-off. When
low, this bit enables main oscillator to run. The
main oscillator is switched off when OSCOFF is
high.
3.1.3 Oscillator Safe Guard
The Oscillator Safe Guard (OSG) affords drastically increased operational integrity in ST62xx devices. The OSG circuit provides three basic functions: it filters spikes from the oscillator lines which
would result in over frequency to the ST62 CPU; it
gives access to the Low Frequency Auxiliary Oscillator (LFAO), used to ensure minimum processing in case of main oscillator failure, to offer reduced power consumption or to provide a fixed
frequency low cost oscillator; finally, it automatically limits the internal clock frequency as a function of supply voltage, in order to ensure correct
operation even if the power supply should drop.
The OSG is enabled or disabled by choosing the
relevant OSG option. It may be viewed as a filter
whose cross-over frequency is device dependent.
Spikes on the oscillator lines result in an effectively increased internal clock frequency. In the absence of an OSG circuit, this may lead to an over
frequency for a given power supply voltage. The
OSG filters out such spikes (as illustrated inFigure 9.). In all cases, when the OSG is active, the
maximum internal clock frequency, fINT, is limited
to fOSG, which is supply voltage dependent. This
relationship is illustrated inFigure 12..
When the OSG is enabled, the Low Frequency
Auxiliary Oscillator may be accessed. This oscillator starts operating after the first missing edge of
the main oscillator (see Figure 10.).
Over-frequency, at a given power supply level, is
seen by the OSG as spikes; it therefore filters out
some cycles in order that the internal clock frequency of the device is kept within the range the
particular device can stand (depending on VDD),
and below fOSG: the maximum authorised frequency with OSG enabled.
Note. The OSG should be used wherever possible as it provides maximum safety. Care must be
taken, however, as it can increase power consumption and reduce the maximum operating frequency to fOSG.
19/82
18
ST62T35B/E35B
CLOCK SYSTEM (Cont’d)
Figure 9. OSG Filtering Principle
(1)
(2)
(3)
(4)
(1) Maximum Frequency for the device to work correctly
(2) Actual Quartz Crystal Frequency at OSCin pin
(3) Noise from OSCin
(4) Resulting Internal Frequency
VR001932
Figure 10. OSG Emergency Oscillator Principle
Main
Oscillator
Emergency
Oscillator
Internal
Frequency
VR001933
20/82
19
ST62T35B/E35B
CLOCK SYSTEM (Cont’d)
Figure 11. Clock Circuit Block Diagram
POR
Core
: 13
OSG
TIMER 1
M
U
X
MAIN
OSCILLATOR
fINT
Watchdog
: 12
M
U
X
:6
ADC
LFAO
:1
ARTIMER 16
Main Oscillator off
Figure 12. Maximum Operating Frequency (fMAX) versus Supply Voltage (VDD)
Maximum FREQUENCY (MHz)
8
FUNCTIONALITY IS NOT
GUARANTEED
IN THIS AREA
7
6
5
4
3
3
4
fOSG
2
fOSG Min
2
1
1
2.5
3
3.5
4
4.5
5
5.5
6
SUPPLY VOLTAGE (VDD)
VR01807
Notes:
1. In this area, operation is guaranteed at the
quartz crystal frequency.
2. When the OSG is disabled, operation in this
area is guaranteed at the crystal frequency. When
the OSG is enabled, operation in this area is guaranteed at a frequency of at least fOSG Min.
3. When the OSG is disabled, operation in this
area is guaranteed at the quartz crystal frequency.
When the OSG is enabled, access to this area is
prevented. The internal frequency is kept a OSG.
f
4. When the OSG is disabled, operation in this
area is not guaranteed
When the OSG is enabled, access to this area is
prevented. The internal frequency is kept at OSG.
f
21/82
20
ST62T35B/E35B
3.2 RESETS
The MCU can be reset in three ways:
– by the external Reset input being pulled low;
– by Power-on Reset;
– by the digital Watchdog peripheral timing out.
3.2.1 RESET Input
The RESET pin may be connected to a device of
the application board in order to reset the MCU if
required. The RESET pin may be pulled low in
RUN, WAIT or STOP mode. This input can be
used to reset the MCU internal state and ensure a
correct start-up procedure. The pin is active low
and features a Schmitt trigger input. The internal
Reset signal is generated by adding a delay to the
external signal. Therefore even short pulses on
the RESET pin are acceptable, provided VDD has
completed its rising phase and that the oscillator is
running correctly (normal RUN or WAIT modes).
The MCU is kept in the Reset state as long as the
RESET pin is held low.
The internal delay is generated by an on-chip counter. The internal reset line is released 2048 internal
clock cycles after release of the external reset.
Notes:
To ensure correct start-up, the user should take
care that the reset signal is not released before
the VDD level is sufficient to allow MCU operation
at the chosen frequency (see Recommended Operating Conditions).
A proper reset signal for a slow rising VDD supply
can generally be provided by an external RC network connected to theRESET pin.
Figure 13. Reset and Interrupt Processing
RESET
NMI MASK SET
INT LATCH CLEARED
( IF PRESENT )
If RESET activation occurs in the RUN or WAIT
modes, processing of the user program is stopped
(RUN mode only), the Inputs and Outputs are configured as inputs with pull-up resistors and the
main Oscillator is restarted. When the level on the
RESET pin then goes high, the initialization sequence is executed following expiry of the internal
delay period.
If RESET pin activation occurs in the STOP mode,
the oscillator starts up and all Inputs and Outputs
are configured as inputs with pull-up resistors.
When the level of the RESET pin then goes high,
the initialization sequence is executed following
expiry of the internal delay period.
3.2.2 Power-on Reset
The function of the POR circuit consists in waking
up the MCU at an appropriate stage during the
power-on sequence. At the beginning of this sequence, the MCU is configured in the Reset state:
all I/O ports are configured as inputs with pull-up
resistors and no instruction is executed. When the
power supply voltage rises to a sufficient level, the
oscillator starts to operate, whereupon an internal
delay is initiated, in order to allow the oscillator to
fully stabilize before executing the first instruction.
The initialization sequence is executed immediately following the internal delay.
22/82
21
SELECT
NMI MODE FLAGS
PUT FFEH
ON ADDRESS BUS
YES
IS RESET STILL
PRESENT?
NO
LOAD PC
FROM RESET LOCATIONS
FFE/FFF
FETCH INSTRUCTION
VA000427
ST62T35B/E35B
RESETS (Cont’d)
3.2.3 Watchdog Reset
The MCU provides a Watchdog timer function in
order to ensure graceful recovery from software
upsets. If the Watchdog register is not refreshed
before an end-of-count condition is reached, the
internal reset will be activated. This, amongst other things, resets the watchdog counter.
The MCU restarts just as though the Reset had
been generated by the RESET pin, including the
built-in stabilisation delay period.
3.2.4 Application Notes
Reset, the Interrupt flag is automatically set, so
that the CPU is in Non Maskable Interrupt mode;
this prevents the initialisation routine from being
interrupted. The initialisation routine should therefore be terminated by a RETI instruction, in order
to revert to normal mode and enable interrupts. If
no pending interrupt is present at the end of the initialisation routine, the MCU will continue by
processing the instruction immediately following
the RETI instruction. If, however, a pending interrupt is present, it will be serviced.
Figure 14. Reset and Interrupt Processing
No external resistor is required between VDD and
the Reset pin, thanks to the built-in pull-up device.
The POR circuit operates dynamically, in that it
triggers MCU initialization on detecting the rising
edge of VDD. The typical threshold is in the region
of 2 volts, but the actual value of the detected
threshold depends on the way in which VDD rises.
RESET
JP
JP:2 BYTES/4 CYCLES
RESET
VECTOR
The POR circuit is NOT designed to supervise
static, or slowly rising or falling VDD.
3.2.5 MCU Initialization Sequence
When a reset occurs the stack is reset, the PC is
loaded with the address of the Reset Vector (located in program ROM starting at address
0FFEh). A jump to the beginning of the user program must be coded at this address. Following a
INITIALIZAT ION
ROUTINE
RETI: 1 BYTE/2 CYCLES
RETI
VA00181
Figure 15. Reset Block Diagram
VDD
fOSC
300kΩ
RESET
ST6
INTERNAL
RESET
CK
COUNTE R
RESET
RESET
2.8kΩ
POWER ON RESET
WATC HDOG RESET
VA0200B
23/82
22
ST62T35B/E35B
RESETS (Cont’d)
Table 7. Register Reset Status
Register
Address(es)
0DBh
0DFh
0C0h to 0C2h
0C4h to 0C6h
0CCh to 0CEh
0C8h
0D4h
Oscillator Control Register
EEPROM Control Register
Port Data Registers
Port Direction Register
Port Option Register
Interrupt Option Register
TIMER Status/Control
AR
AR
AR
AR
TIMER
TIMER
TIMER
TIMER
Status/Control 1
Status/Control 2
Status/Control 3
Status/Control 4
Register
Register
Register
Register
0DCh to 0DDh
X, Y, V, W, Register
Accumulator
Data RAM
Data RAM Page REgister
Data ROM Window Register
EEPROM
A/D Result Register
AR TIMER Capture Register
AR TIMER Reload/Capture Register
ARTIMER Mask Registers
ARTIMER Compare Registers
080H TO 083H
0FFh
084h to 0BFh
0CBh
0C9h
00h to 03Fh
0D0h
0DBh
0D9h
OE0h-OEFh
OEDh-OEEh
TIMER Counter Register
TIMER Prescaler Register
Watchdog Counter Register
A/D Control Register
0D3h
0D2h
0D8h
0D1h
UART Control
UART Data Register
OD7h
OD6h
23
Comment
Main oscillator on
EEPROM enabled
I/O are Input with or without pull-up
depending on PORT PULL option
00h
0E8h
0E1h
0E2h
OE3h
SPI Registers
24/82
Status
Interrupt disabled
TIMER disabled
AR TIMER stopped
SPI disabled
Undefined
FFh
7Fh
FEh
40h
As written if programmed
Max count loaded
A/D in Standby
UART disabled
ST62T35B/E35B
3.3 INTERRUPTS
The CPU can manage four Maskable Interrupt
sources, in addition to a Non Maskable Interrupt
source (top priority interrupt). Each source is associated with a specific Interrupt Vector which
contains a Jump instruction to the associated interrupt service routine. These vectors are located
in Program space (see Table 8 ).
When an interrupt source generates an interrupt
request, and interrupt processing is enabled, the
PC register is loaded with the address of the interrupt vector (i.e. of the Jump instruction), which
then causes a Jump to the relevant interrupt service routine, thus servicing the interrupt.
Interrupt sources are linked to events either on external pins, or on chip peripherals. Several events
can be ORed on the same interrupt source, and
relevant flags are available to determine which
event triggered the interrupt.
The Non Maskable Interrupt request has the highest priority and can interrupt any interrupt routine
at any time; the other four interrupts cannot interrupt each other. If more than one interrupt request
is pending, these are processed by the processor
core according to their priority level: source #1 has
the higher priority while source #4 the lower. The
priority of each interrupt source is fixed.
Table 8. Interrupt Vector Map
Interrupt Source
Interrupt source #0
Interrupt source #1
Interrupt source #2
Interrupt source #3
Interrupt source #4
Priority
1
2
3
4
5
Vector Address
(FFCh-FFDh)
(FF6h-FF7h)
(FF4h-FF5h)
(FF2h-FF3h)
(FF0h-FF1h)
matically reset by the core at the beginning of the
non-maskable interrupt service routine.
Interrupt request from source #1 can be configured either as edge or level sensitive by setting
accordingly the LES bit of the Interrupt Option
Register (IOR).
Interrupt request from source #2 are always edge
sensitive. The edge polarity can be configured by
setting accordingly the ESB bit of the Interrupt Option Register (IOR).
Interrupt request from sources #3 & #4 are level
sensitive.
In edge sensitive mode, a latch is set when a edge
occurs on the interrupt source line and is cleared
when the associated interrupt routine is started.
So, the occurrence of an interrupt can be stored,
until completion of the running interrupt routine before being processed. If several interrupt requests
occurs before completion of the running interrupt
routine, only the first request is stored.
Storage of interrupt requests is not available in
level sensitive mode. To be taken into account,
the low level must be present on the interrupt pin
when the MCU samples the line after instruction
execution.
At the end of every instruction, the MCU tests the
interrupt lines: if there is an interrupt request the
next instruction is not executed and the appropriate interrupt service routine is executed instead.
Table 9. Interrupt Option Register Description
GEN
SET
Enable all interrupts
CLEARED
Disable all interrupts
Rising edge mode on interrupt source #2
Falling edge mode on interrupt source #2
Level-sensitive mode on interrupt source #1
Falling edge mode on interrupt source #1
SET
3.3.1 Interrupt request
All interrupt sources but the Non Maskable Interrupt source can be disabled by setting accordingly
the GEN bit of the Interrupt Option Register (IOR).
This GEN bit also defines if an interrupt source, including the Non Maskable Interrupt source, can
restart the MCU from STOP/WAIT modes.
Interrupt request from the Non Maskable Interrupt
source #0 is latched by a flip flop which is auto-
ESB
CLEARED
SET
LES
CLEARED
OTHERS
NOT USED
25/82
24
ST62T35B/E35B
IINTERRUPTS (Cont’d)
3.3.2 Interrupt Procedure
The interrupt procedure is very similar to a call
procedure, indeed the user can consider the interrupt as an asynchronous call procedure. As this is
an asynchronous event, the user cannot know the
context and the time at which it occurred. As a result, the user should save all Data space registers
which may be used within the interrupt routines.
There are separate sets of processor flags for normal, interrupt and non-maskable interrupt modes,
which are automatically switched and so do not
need to be saved.
The following list summarizes the interrupt procedure:
MCU
– The interrupt is detected.
– The C and Z flags are replaced by the interrupt
flags (or by the NMI flags).
– The PC contents are stored in the first level of
the stack.
– The normal interrupt lines are inhibited (NMI still
active).
– The first internal latch is cleared.
– The associated interrupt vector is loaded in thePC.
WARNING: In some circumstances, when a
maskable interrupt occurs while the ST6 core is in
NORMAL mode and especially during the execution of an ”ldi IOR, 00h” instruction (disabling all
maskable interrupts): if the interrupt arrives during
the first 3 cycles of the ”ldi” instruction (which is a
4-cycle instruction) the core will switch to interrupt
mode BUT the flags CN and ZN will NOT switch to
the interrupt pair CI and ZI.
User
– User selected registers are saved within the interrupt service routine (normally on a software
stack).
– The source of the interrupt is found by polling the
interrupt flags (if more than one source is associated with the same vector).
– The interrupt is serviced.
– Return from interrupt (RETI)
26/82
25
MCU
– Automatically the MCU switches back to the normal flag set (or the interrupt flag set) and pops
the previous PC value from the stack.
The interrupt routine usually begins by the identifying the device which generated the interrupt request (by polling). The user should save the registers which are used within the interrupt routine in a
software stack. After the RETI instruction is executed, the MCU returns to the main routine.
Figure 16. Interrupt Processing Flow Chart
INS TRUC TION
FETCH
IN STRU CTION
EXEC UTE
INS TRUCT ION
W AS
THE IN STRU CTION
A RE TI ?
LOAD PC FROM
IN TERR UPT VEC TOR
NO
(FFC/ FFD)
YES
YES
IS THE COR E
ALREADY IN
NOR MAL MOD E?
?
SET
INTERR UP T MASK
NO
C LEAR
INTER RU PT MASK
SELECT
PROGRAM FLAGS
PUSH THE
PC INTO THE STAC K
SELECT
INTE RN AL MODE FLAG
”POP”
THE STAC KED PC
C HEC K IF THER E IS
AN IN TERRU PT RE QUEST
AN D INT ER RU PT MASK
NO
?
YES
VA000014
ST62T35B/E35B
IINTERRUPTS (Cont’d)
3.3.3 Interrupt Option Register (IOR)
The Interrupt Option Register (IOR) is used to enable/disable the individual interrupt sources and to
select the operating mode of the external interrupt
inputs. This register is write-only and cannot be
accessed by single-bit operations.
Address: 0C8h — Write Only
Reset status: 00h
7
0
-
LES
ESB
GEN
-
-
-
-
Bit 7, Bits 3-0 = Unused.
Bit 6 = LES: Level/Edge Selection bit.
When this bit is set to one, the interrupt source #1
is level sensitive. When cleared to zero the edge
sensitive mode for interrupt request is selected.
Bit 5 = ESB: Edge Selection bit.
The bit ESB selects the polarity of the interrupt
source #2.
Bit 4 = GEN: Global Enable Interrupt. When this
bit is set to one, all interrupts are enabled. When
this bit is cleared to zero all the interrupts (excluding NMI) are disabled.
When the GEN bit is low, the NMI interrupt is active but cannot cause a wake up from STOP/WAIT
modes.
This register is cleared on reset.
3.3.4 Interrupt sources
Interrupt
sources
available
on
the
ST62E35B/T35B are summarized in theTable 10
with associated mask bit to enable/disable the interrupt request.
Table 10. Interrupt Requests and Mask Bits
GENERAL
TIMER
A/D CONVERTER
IOR
TSCR1
ADCR
Address
Register
C8h
D4h
D1h
UART
UARTCR
D7h
SCR1
SCR2
SCR3
SCR3
SCR3
SPI
ORPA-DRPA
ORPB-DRPB
ORPC-DRPC
ORPD-DRPD
ORPE-DRPE
E8h
E1h
E2h
E2h
E2h
DCh
C0h-C4h
C1h-C5h
C2h-C6h
C3h-C7h
FCh-FDh
Peripheral
ARTIMER
SPI
Port
Port
Port
Port
Port
PAn
PBn
PCn
PDn
PEn
Register
Mask bit
Masked Interrupt Source
GEN
ETI
EAI
RXIEN
TXIEN
OVFIEN
CP1IEN
CP2IEN
ZEROIEN
CMPIEN
ALL
ORPAn-DRPAn
ORPBn-DRPBn
ORPCn-DRPCn
ORPDn-DRPDn
ORPEn-DRPEn
All Interrupts, excluding NMI
TMZ: TIMER Overflow
EOC: End of Conversion
RXRDY : Byte received
TXMT : Byte sent
OVFFLG: ARTIMER Overflow
CP1FLG
CP2FLG
ZEROFLG: Compare to zero flag
CMPFLG: Compare flag
End of Transmission
PAn pin
PBn pin
PCn pin
PDn pin
PEn pin
Interrupt
source
All
source 4
source 4
source 4
source 3
source
source
source
source
source
source
1
1
2
0
2
1
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ST62T35B/E35B
IINTERRUPTS (Cont’d)
Interrupt Polarity Register (IPR)
Address: DAh —
set, IPR is cleared and all port interrupts are not
inverted (e.g. Port C generates interrupts on falling edges).
Read/Write
7
0
-
-
-
Bit 7 - Bits 5 = Unused.
PortE PortD PortC PortA PortB
Bit 4 = Port E Interrupt Polarity.
Bit 3 = Port D Interrupt Polarity.
In conjunction with IOR register ESB bit, the polarity of I/O pins triggered interrupts can be selected
by setting accordingly the Interrupt Polarity Register (IPR). If a bit in IPR is set to one the corresponding port interrupt is inverted (e.g. IPR bit 2 =
1 ; port C generates interrupt on rising edge. At re-
Bit 2 = Port C Interrupt Polarity.
Bit 1= Port A Interrupt Polarity.
Bit 0 = Port B Interrupt Polarity.
Tables 11. I/O Interrupts selections according to IPR, IOR programming
GEN
IPR3
IPR0
IOR5
Port B occurence
Port D occurence
Interrupt
source
1
1
1
1
1
1
1
1
0
0
0
0
0
1
1
1
1
X
0
0
1
1
0
0
1
1
X
0
1
0
1
0
1
0
1
X
falling edge
rising edge
rising edge
falling edge
falling edge
rising edge
rising edge
falling edge
Disabled
falling edge
rising edge
falling edge
rising edge
rising edge
falling edge
rising edge
falling edge
Disabled
2
GEN
IPR4
IPR1
IOR6
Port A occurence
Port E occurence
Interrupt
source
1
1
1
1
1
1
1
1
0
0
0
0
0
1
1
1
1
X
0
0
1
1
0
0
1
1
X
0
1
0
1
0
1
0
1
X
falling edge
low level
rising edge
high level
falling edge
low level
rising edge
high level
Disabled
falling edge
low level
falling edge
low level
rising edge
high level
rising edge
high level
Disabled
1
IPR2
0
1
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Port C occurence
falling edge
rising edge
Interrupt source
0
ST62T35B/E35B
INTERRUPTS (Cont’d)
Figure 17. Interrupt Block Diagram
FROM REGISTER PORT A,B,C,D,E
SINGLE BIT ENABLE
PBE
IPR Bit 2
VDD
FF
CLK
Q
CLR
PORT C
Bits
NMI
INT #0 NMI (FFC,D))
I0 Start
IPR Bit 0
PORT A
Bits
FF
CLK
Q
CLR
PBE
0
MUX
INT #1 (FF6,7)
I1 Start
IPR Bit 4
1
PORT E
Bits
PBE
IOR bit 6 (LES)
SPI
RESTA RT
FROM
STOP/WAIT
IPR Bit 1
PORT B
Bits
FF
CLK
Q
CLR
PBE
IOR bit 5 (ESB)
INT #2 (FF4,5)
I2 Start
IPR Bit 3
PORT D
Bits
PBE
CP1FLG
CP1IEN
CP2FLG
CP2IEN
OVFLG
OVFIEN
CMPFLG
CMPIEN
ZEROFLG
ZEROIEN
INT #3 (FF2,3)
TMZ
ETI
EAI
EOC
INT #4 (FF0,1)
RXRDY
RXIEN
TXMT
TXIEN
IOR bit 4(GEN)
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ST62T35B/E35B
3.4 POWER SAVING MODES
The WAIT and STOP modes have been implemented in the ST62xx family of MCUs in order to
reduce the product’s electrical consumption during idle periods. These two power saving modes
are described in the following paragraphs.
3.4.1 WAIT Mode
The MCU goes into WAIT mode as soon as the
WAIT instruction is executed. The microcontroller
can be considered as being in a “software frozen”
state where the core stops processing the program instructions, the RAM contents and peripheral registers are preserved as long as the power
supply voltage is higher than the RAM retention
voltage. In this mode the peripherals are still active.
WAIT mode can be used when the user wants to
reduce the MCU power consumption during idle
periods, while not losing track of time or the capability of monitoring external events. The active oscillator is not stopped in order to provide a clock
signal to the peripherals. Timer counting may be
enabled as well as the Timer interrupt, before entering the WAIT mode: this allows the WAIT mode
to be exited when a Timer interrupt occurs. The
same applies to other peripherals which use the
clock signal.
If the WAIT mode is exited due to a Reset (either
by activating the external pin or generated by the
Watchdog), the MCU enters a normal reset procedure. If an interrupt is generated during WAIT
mode, the MCU’s behaviour depends on the state
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of the processor core prior to the WAIT instruction,
but also on the kind of interrupt request which is
generated. This is described in the following paragraphs. The processor core does not generate a
delay following the occurrence of the interrupt, because the oscillator clock is still available and no
stabilisation period is necessary.
3.4.2 STOP Mode
If the Watchdog is disabled, STOP mode is available. When in STOP mode, the MCU is placed in
the lowest power consumption mode. In this operating mode, the microcontroller can be considered
as being “frozen”, no instruction is executed, the
oscillator is stopped, the RAM contents and peripheral registers are preserved as long as the
power supply voltage is higher than the RAM retention voltage, and the ST62xx core waits for the
occurrence of an external interrupt request or a
Reset to exit the STOP state.
If the STOP state is exited due to a Reset (by activating the external pin) the MCU will enter a normal reset procedure. Behaviour in response to interrupts depends on the state of the processor
core prior to issuing the STOP instruction, and
also on the kind of interrupt request that is generated.
This case will be described in the following paragraphs. The processor core generates a delay after occurrence of the interrupt request, in order to
wait for complete stabilisation of the oscillator, before executing the first instruction.
ST62T35B/E35B
POWER SAVING MODE (Cont’d)
3.4.3 Exit from WAIT and STOP Modes
The following paragraphs describe how the MCU
exits from WAIT and STOP modes, when an interrupt occurs (not a Reset). It should be noted that
the restart sequence depends on the original state
of the MCU (normal, interrupt or non-maskable interrupt mode) prior to entering WAIT or STOP
mode, as well as on the interrupt type.
Interrupts do not affect the oscillator selection.
3.4.3.1 Normal Mode
If the MCU was in the main routine when the WAIT
or STOP instruction was executed, exit from Stop
or Wait mode will occur as soon as an interrupt occurs; the related interrupt routine is executed and,
on completion, the instruction which follows the
STOP or WAIT instruction is then executed, providing no other interrupts are pending.
3.4.3.2 Non Maskable Interrupt Mode
If the STOP or WAIT instruction has been executed during execution of the non-maskable interrupt
routine, the MCU exits from the Stop or Wait mode
as soon as an interrupt occurs: the instruction
which follows the STOP or WAIT instruction is executed, and the MCU remains in non-maskable interrupt mode, even if another interrupt has been
generated.
3.4.3.3 Normal Interrupt Mode
If the MCU was in interrupt mode before the STOP
or WAIT instruction was executed, it exits from
STOP or WAIT mode as soon as an interrupt occurs. Nevertheless, two cases must be considered:
– If the interrupt is a normal one, the interrupt routine in which the WAIT or STOP mode was en-
tered will be completed, starting with the
execution of the instruction which follows the
STOP or the WAIT instruction, and the MCU is
still in the interrupt mode. At the end of this routine pending interrupts will be serviced in accordance with their priority.
– In the event of a non-maskable interrupt, the
non-maskable interrupt service routine is processed first, then the routine in which the WAIT or
STOP mode was entered will be completed by
executing the instruction following the STOP or
WAIT instruction. The MCU remains in normal
interrupt mode.
Notes:
To achieve the lowest power consumption during
RUN or WAIT modes, the user program must take
care of:
– configuring unused I/Os as inputs without pull-up
(these should be externally tied to well defined
logic levels);
– placing all peripherals in their power down
modes before entering STOP mode;
When the hardware activated Watchdog is selected, or when the software Watchdog is enabled,
the STOP instruction is disabled and a WAIT instruction will be executed in its place.
If all interrupt sources are disabled (GEN low), the
MCU can only be restarted by a Reset. Although
setting GEN low does not mask the NMI as an interrupt, it will stop it generating a wake-up signal.
The WAIT and STOP instructions are not executed if an enabled interrupt request is pending.
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ST62T35B/E35B
4 ON-CHIP PERIPHERALS
4.1 I/O PORTS
The MCU features Input/Output lines which may
be individually programmed as any of the following input or output configurations:
– Input without pull-up or interrupt
– Input with pull-up and interrupt
– Input with pull-up, but without interrupt
– Analog input
– Push-pull output
– Open drain output
The lines are organised as bytewise Ports.
Each port is associated with 3 registers in Data
space. Each bit of these registers is associated
with a particular line (for instance, bits 0 of Port A
Data, Direction and Option registers are associated with the PA0 line of Port A).
The DATA registers (DRx), are used to read the
voltage level values of the lines which have been
configured as inputs, or to write the logic value of
the signal to be output on the lines configured as
outputs. The port data registers can be read to get
the effective logic levels of the pins, but they can
be also written by user software, in conjunction
with the related option registers, to select the different input mode options.
Single-bit operations on I/O registers are possible
but care is necessary because reading in input
mode is done from I/O pins while writing will directly affect the Port data register causing an undesired change of the input configuration.
The Data Direction registers (DDRx) allow the
data direction (input or output) of each pin to be
set.
The Option registers (ORx) are used to select the
different port options available both in input and in
output mode.
All I/O registers can be read or written to just as
any other RAM location in Data space, so no extra
RAM cells are needed for port data storage and
manipulation. During MCU initialization, all I/O
registers are cleared and the input mode with pullups and no interrupt generation is selected for all
the pins, thus avoiding pin conflicts.
Figure 18. I/O Port Block Diagram
SIN CONTROLS
RESET
VDD
DATA
DIRECTION
REGISTER
VDD
INPUT/OUTPUT
DATA
REGISTER
SHIF T
REGISTER
OPTION
REGISTER
SOUT
TO INTER RUPT
TO ADC
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VA00413
ST62T35B/E35B
I/O PORTS (Cont’d)
4.1.1 Operating Modes
Each pin may be individually programmed as input
or output with various configurations.
This is achieved by writing the relevant bit in the
Data (DR), Data Direction (DDR) and Option registers (OR). Table 12 illustrates the various port
configurations which can be selected by user software.
4.1.1.1 Input Options
Pull-up, High Impedance Option. All input lines
can be individually programmed with or without an
internal pull-up by programming the OR and DR
registers accordingly. If the pull-up option is not
selected, the input pin will be in the high-impedance state.
4.1.1.2 Interrupt Options
All input lines can be individually connected by
software to the interrupt system by programming
the OR and DR registers accordingly. The interrupt trigger modes (falling edge, rising edge and
low level) can be configured by software as described in the Interrupt Chapter for each port.
4.1.1.3 Analog Input Options
Some pins can be configured as analog inputs by
programming the OR and DR registers accordingly. These analog inputs are connected to the onchip 8-bit Analog to Digital Converter. ONLY ONE
pin should be programmed as an analog input at
any time, since by selecting more than one input
simultaneously their pins will be effectively shorted.
Table 12. I/O Port Option Selection
DDR
OR
DR
Mode
0
0
0
Input
With pull-up, no interrupt
Option
0
0
1
Input
No pull-up, no interrupt
0
1
0
Input
With pull-up and with interrupt
0
1
1
Input
Analog input (when available)
1
0
X
Output
Open-drain output (20mA sink when available)
1
1
X
Output
Push-pull output (20mA sink when available)
Note: X = Don’t care
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ST62T35B/E35B
I/O PORTS (Cont’d)
4.1.2 Safe I/O State Switching Sequence
Switching the I/O ports from one state to another
should be done in a sequence which ensures that
no unwanted side effects can occur. The recommended safe transitions are illustrated in Figure
19.. All other transitions are potentially risky and
should be avoided when changing the I/O operating mode, as it is most likely that undesirable sideeffects will be experienced, such as spurious interrupt generation or two pins shorted together by the
analog multiplexer.
Single bit instructions (SET, RES, INC and DEC)
should be used with great caution on Ports Data
registers, since these instructions make an implicit
read and write back of the entire register. In port
input mode, however, the data register reads from
the input pins directly, and not from the data register latches. Since data register information in input
mode is used to set the characteristics of the input
pin (interrupt, pull-up, analog input), these may be
unintentionally reprogrammed depending on the
state of the input pins. As a general rule, it is better
to limit the use of single bit instructions on data
registers to when the whole (8-bit) port is in output
mode. In the case of inputs or of mixed inputs and
outputs, it is advisable to keep a copy of the data
register in RAM. Single bit instructions may then
be used on the RAM copy, after which the whole
copy register can be written to the port data register:
SET bit, datacopy
LD a, datacopy
LD DRA, a
Care must also be taken to not use INC or DEC instructions on a port register when the 8 bits are not
available on the devices.
The WAIT and STOP instructions allow the
ST62xx to be used in situations where low power
consumption is needed. The lowest power consumption is achieved by configuring I/Os in input
mode with well-defined logic levels.
The user must take care not to switch outputs with
heavy loads during the conversion of one of the
analog inputs in order to avoid any disturbance to
the conversion.
Figure 19. Diagram showing Safe I/O State Transitions
Interrupt
pull-up
010*
011
Input
Analog
Input
pull-up (Reset
state)
000
001
Input
Output
Open Drain
100
101
Output
Open Drain
Output
Push-pull
110
111
Output
Push-pull
Note *. xxx = DDR, OR, DR Bits respectively
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ST62T35B/E35B
I/O PORTS (Cont’d)
Table 13. I/O Port configuration for the ST62T35B
MODE
Input
(Reset state if PORT
PULL option disabled)
Input
with pull up
(Reset state if PORT
PULL option enabled)
Input
with pull up
with interrupt
Analog Input
Open drain output
5mA
AVAILABLE ON(1)
PA0-PA7
PB0-PB7
PC4-PC7
PD0-PD7
PE0-PE7
Data in
Interrupt
PA0-PA7
PB0-PB7
PC4-PC7
PD0-PD7
PE0-PE7
Data in
Interrupt
PA0-PA7
PB0-PB7
PC4-PC7
PD0-PD7
PE0-PE7
PA4-PA7
PB0-PB7
PC4-PC7
PD0-PD7
PA4-PA7
PB0-PB7
PC4-PC7
PD0-PD7
Open drain output
20mA
PA0-PA3
PE0-PE7
Push-pull output
5mA
PA4-PA7
PB0-PB7
PC4-PC7
PD0-PD7
Push-pull output
20mA
SCHEMATIC
PA0-PA3
PE0-PE7
Data in
Interrupt
ADC
Data out
Data out
VR01992A
Note 1. Provided the correct configuration has been selected.
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ST62T35B/E35B
I/O PORTS (Cont’d)
4.1.3 ARTimer alternate functions
As long as PWMEN (resp. OVFEN) bit is kept low,
the PA3/PWM (resp. PA2/OVF) pin is used as
standard I/O pin and therefore can be configured
in any mode through the DDR and OR registers.
If PWMEN (resp. OVFEN) bit is set, PA3/PWM
(resp. PA2/OVF) pin must be configured as output
through the DDR and OR registers to be used as
PWM (OVF) output of the ARTimer16. All output
modes are available.
PA4/CP1 or PA5/CP2 pins must be configured as
input through DDR register to allow CP1 or CP2
triggered input capture of the ARTimer16. All input
modes are available and I/O’s can be read independantly of the ARTimer at any time. As long as
RLDSEL2, RLDSEL1 bits do not enable CP1 or
CP2 triggered capture, PA4/CP1 and PA5/CP2 are
standard I/O’s configurable through DDR and OR
registers.
4.1.4 SPI alternate functions
PD2/Sin and PD1/Scl pins must be configured as
input through the DDR and OR registers to be
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used as data in and data clock (Slave mode) for
the SPI. All input modes are available and I/O’s
can be read independantly of the SPI at any time.
PD3/Sout must be configured in open drain output
mode to be used as data out for the SPI. In output
mode, the value present on the pin is the port data
register content only if PD3 is defined as push pull
output, while serial transmission is possible only in
open drain mode.
4.1.5 UART alternate functions
PD4/RXD1 pin must be configured as input
through the DDR and OR registers to be used as
reception line for the UART. All input modes are
available and PD4 can be read independantly of
the UART at any time.
PD5/TXD1 pin must be configured as output
through the DDR and OR registers to be used as
transmission line for the UART. Value present on
the pin in output mode is the Data register content
as long as no transmission is active.
ST62T35B/E35B
I/O PORTS (Cont’d)
Figure 20. Peripheral Interface Configuration of SPI, UART and AR Timer16
VDD
PID
RXD
PD4/RXD1
DR
UART
IARTOE
PID
MUX
PD5/TXD1
0
1
DR
TXD
PID PP/OD
OPR
MUX
PD3/Sout
1
0
DR
OUT
PID
IN
DR
PD2/Sin
SYNCHRONOUS
SERIAL I/O
PID
CLOCK
DR
PD1/Scl
PWMEN
PID
MUX
PA3/PWM
1
0
PWM
DR
PID
CP1
DR
PA4/CP1
ARTIMER 16
PID
CP2
DR
PA5/CP2
OVFEN
PID
PA2/OVF
MUX
1
0
OVF
DR
VR01661D
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ST62T35B/E35B
I/O PORTS (Cont’d)
4.1.6 I/O Port Option Registers
4.1.8 I/O Port Data Registers
ORA/B/C/D/E (CCh PA, CDh PB, CEh PC, CFh
PD, FEh PE)
Read/Write
DRA/B/C/D/E (C0h PA, C1h PB, C2h PC, C3h
PD, FCh PE)
Read/Write
7
Px7
Px6
Px5
Px4
Px3
Px2
Px1
0
7
Px0
Px7
Bit 7-0 = Px7 - Px0: Port A, B, C, D and E Option
Register bits.
4.1.7 I/O Port Data Direction Registers
DDRA/B/C/D/E (C4h PA, C5h PB, C6h PC, C7h
PD, FDh PE)
Read/Write
7
Px7
0
Px6
Px5
Px4
Px3
Px2
Px1
Px0
Bit 7-0 = Px7 - Px0: Port A, B, C, D and E Data Direction Registers bits.
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0
Px6
Px5
Px4
Px3
Px2
Px1
Px0
Bit 7-0 = Px7 - Px0: Port A, B, C, D and E Data
Registers bits.
ST62T35B/E35B
4.2 TIMER
The MCU features an on-chip Timer peripheral,
consisting of an 8-bit counter with a 7-bit programmable prescaler, giving a maximum count of 215.
The peripheral may be configured in three different operating modes.
Figure 1 shows the Timer Block Diagram. The external TIMER pin is available to the user. The content of the 8-bit counter can be read/written in the
Timer/Counter register, TCR, while the state of the
7-bit prescaler can be read in the PSC register.
The control logic device is managed in the TSCR
register as described in the following paragraphs.
The 8-bit counter is decremented by the output
(rising edge) coming from the 7-bit prescaler and
can be loaded and read under program control.
When it decrements to zero then the TMZ (Timer
Zero) bit in the TSCR is set to “1”. If the ETI (Enable Timer Interrupt) bit in the TSCR is also set to
“1”, an interrupt request is generated as described
in the Interrupt Chapter. The Timer interrupt can
be used to exit the MCU from WAIT mode.
The prescaler input can be the internal frequency
fINT divided by 12 or an external clock applied to
the TIMER pin. The prescaler decrements on the
rising edge. Depending on the division factor programmed by PS2, PS1 and PS0 bits in the TSCR.
The clock input of the timer/counter register is
multiplexed to different sources. For division factor
1, the clock input of the prescaler is also that of
timer/counter; for factor 2, bit 0 of the prescaler
register is connected to the clock input of TCR.
This bit changes its state at half the frequency of
the prescaler input clock. For factor 4, bit 1 of the
PSC is connected to the clock input of TCR, and
so forth. The prescaler initialize bit, PSI, in the
TSCR register must be set to “1” to allow the prescaler (and hence the counter) to start. If it is
cleared to “0”, all the prescaler bits are set to “1”
and the counter is inhibited from counting. The
prescaler can be loaded with any value between 0
and 7Fh, if bit PSI is set to “1”. The prescaler tap is
selected by means of the PS2/PS1/PS0 bits in the
control register.
Figure 2 illustrates the Timer’s working principle.
Figure 21. Timer Block Diagram
DATABUS 8
8
PSC
8
6
5
4
3
2
1
0
SELECT
1 OF 7
8
b7
8-BIT
COUNTER
b6
b5
b4
b3
b2
b1
b0
STATUS/CONTROL
REGISTER
TMZ
ETI
TOUT
DOUT
PSI
PS2
PS1
PS0
3
TIMER
INTERRUPT
LINE
SYNCHRONIZATION
LOGIC
fOSC
LATCH
:12
VA00009
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ST62T35B/E35B
TIMER (Cont’d)
4.2.1 Timer Operating Modes
There are three operating modes, which are selected by the TOUT and DOUT bits (see TSCR
register). These three modes correspond to the
two clocks which can be connected to the 7-bit
prescaler (fINT ÷ 12 or TIMER pin signal), and to
the output mode.
4.2.1.1 Gated Mode
(TOUT = “0”, DOUT = “1”)
In this mode the prescaler is decremented by the
Timer clock input (fINT ÷ 12), but ONLY when the
signal on the TIMER pin is held high (allowing
pulse width measurement). This mode is selected
by clearing the TOUT bit in the TSCR register to
“0” (i.e. as input) and setting the DOUT bit to “1”.
4.2.1.2 Event Counter Mode
(TOUT = “0”, DOUT = “0”)
In this mode, the TIMER pin is the input clock of
the prescaler which is decremented on the rising
edge.
4.2.1.3 Output Mode
(TOUT = “1”, DOUT = data out)
The TIMER pin is connected to the DOUT latch,
hence the Timer prescaler is clocked by the prescaler clock input (fINT ÷ 12).
The user can select the desired prescaler division
ratio through the PS2, PS1, PS0 bits. When the
TCR count reaches 0, it sets the TMZ bit in the
TSCR. The TMZ bit can be tested under program
control to perform a timer function whenever it
goes high. The low-to-high TMZ bit transition is
used to latch the DOUT bit of the TSCR and transfer it to the TIMER pin. This operating mode allows
external signal generation on the TIMER pin.
Table 14. Timer Operating Modes
TOUT
0
0
1
1
DOUT
0
1
0
1
Timer Pin
Input
Input
Output
Output
Timer Function
Event Counter
Gated Input
Output “0”
Output “1”
4.2.2 Timer Interrupt
When the counter register decrements to zero
with the ETI (Enable Timer Interrupt) bit set to one,
an interrupt request is generated as described in
the Interrupt Chapter. When the counter decrements to zero, the TMZ bit in the TSCR register is
set to one.
Figure 22. Timer Working Principle
7-BIT PRESCALER
BIT0
CLOCK
0
BIT1
BIT2
2
1
BIT3
BIT4
3
4
8-1 MULTIPLEXER
BIT5
5
BIT6
6
7
PS0
PS1
PS2
BIT0
BIT1
BIT2
BIT3
BIT4
BIT5
BIT6
BIT7
8-BIT COUNTER
VA00186
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ST62T35B/E35B
TIMER (Cont’d)
4.2.3 Application Notes
The user can select the presence of an on-chip
pull-up on the TIMER pin as option.
TMZ is set when the counter reaches zero; however, it may also be set by writing 00h in the TCR
register or by setting bit 7 of the TSCR register.
The TMZ bit must be cleared by user software
when servicing the timer interrupt to avoid undesired interrupts when leaving the interrupt service
routine. After reset, the 8-bit counter register is
loaded with 0FFh, while the 7-bit prescaler is loaded with 07Fh, and the TSCR register is cleared.
This means that the Timer is stopped (PSI=“0”)
and the timer interrupt is disabled.
If the Timer is programmed in output mode, the
DOUT bit is transferred to the TIMER pin when
TMZ is set to one (by software or due to counter
decrement). When TMZ is high, the latch is transparent and DOUT is copied to the timer pin. When
TMZ goes low, DOUT is latched.
A write to the TCR register will predominate over
the 8-bit counter decrement to 00h function, i.e. if
a write and a TCR register decrement to 00h occur
simultaneously, the write will take precedence,
and the TMZ bit is not set until the 8-bit counter
reaches 00h again. The values of the TCR and the
PSC registers can be read accurately at any time.
4.2.4 Timer Registers
Bit 4 = DOUT: Data Output
Data sent to the timer output when TMZ is set high
(output mode only). Input mode selection (input
mode only).
Bit 3 = PSI: Prescaler Initialize Bit
Used to initialize the prescaler and inhibit its
counting. When PSI=“0” the prescaler is set to
7Fh and the counter is inhibited. When PSI=“1”
the prescaler is enabled to count downwards. As
long as PSI=“0” both counter and prescaler are
not running.
Bit 2, 1, 0 = PS2, PS1, PS0: Prescaler Mux. Select. These bits select the division ratio of the prescaler register.
Table 15. Prescaler Division Factors
PS2
0
0
0
0
1
1
1
1
PS1
0
0
1
1
0
0
1
1
PS0
0
1
0
1
0
1
0
1
Divided by
1
2
4
8
16
32
64
128
Timer Status Control Register (TSCR)
Address: 0D4h
Timer Counter Register TCR
— Read/Write
7
TMZ
0
ETI
TOUT DOUT
PSI
PS2
PS1
PS0
Address: 0D3h —
Read/Write
7
D7
0
D6
D5
D4
D3
D2
D1
D0
Bit 7 = TMZ: Timer Zero bit
A low-to-high transition indicates that the timer
count register has decrement to zero. This bit
must be cleared by user software before starting a
new count.
Bit 7-0 = D7-D0: Counter Bits.
Bit 6 = ETI: Enable Timer Interrupt
Address: 0D2h —
When set, enables the timer interrupt request. If
ETI=0 the timer interrupt is disabled. If ETI=1 and
TMZ=1 an interrupt request is generated.
Prescaler Register PSC
Read/Write
7
D7
0
D6
D5
D4
D3
D2
D1
D0
Bit 5 = TOUT: Timers Output Control
When low, this bit selects the input mode for the
TIMER pin. When high the output mode is selected.
Bit 7 = D7: Always read as ”0”.
Bit 6-0 = D6-D0: Prescaler Bits.
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ST62T35B/E35B
4.3 ARTIMER 16
The ARTIMER16 is a timer module based on a 16
bit downcounter with Reload, Capture and Compare features to manage timing requirements.
Two outputs provide PWM and Overflow (OVF)
output signals each with programmable polarity,
and two inputs CP1 and CP2 control start-up, capture and/or reload operations on the central counter.
The ARTIMER16 includes four 16-bit registers
CMP,RLCP,MASK and CP for the Reload, Capture and compare functions, four 8-bit status/control registers and the associated control logic.The
16-bit registers are accessed from the 8-bit internal bus. The full 16-bit word is written in two bytes,
the high byte first and then the low byte. The high
byte is stored in an intermediate register and is
written to the target 16-bit register at the same
time as the write to the low byte. This high byte will
remain constant if further writes are made to the
low bytes, until the high byte is changed. Full
Read/Write access is available to all registers except where mentioned.
The ARTIMER16 may be placed into the reset
mode by resetting RUNRES to 0 in order to
achieve lower consumption. The contents of
RLCP, CP, MASK and CMP are not affected, nor
is the previous run mode of the timer changed. If
RUNRES is subsequently set to 1, the timer restarts in the same RUN mode as previously set if
no changes are made to the timer status registers.
Finally, interrupt capabilities are associated to the
Reload, Capture and Compare features.
Figure 23. . ARTIMER16 Block Diagram
8
SCR1
PSC
16-Bit
16
fINT
CMP
8
SCR2
16
8-Bit MCU DATA BUS
4
8
BUS INTERFACE
SCR4
16-Bit DATA BUS
8
SCR3
Compare
PWM
Compare-to-0
OVF
16-Bit
MASK
16
16-Bit
RLCP
16
COUNTER
16
16-Bit
CP
CP1
INT
CONTROL LOGIC
CP2
VR02014
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ST62T35B/E35B
4.3.1 CENTRAL COUNTER
The core of the 16 bit Auto-Reload Timer is a 16bit synchronous downcounter which accepts the
MCU internal clock through a prescaler with a programmable ratio (1/1, 1/4, 1/16).
The maximum time for downcounting is therefore
216 x Psc x Tclk where Psc is the prescaler ratio,
and Tclk the period of the main oscillator.
This down counter is stopped and its content kept
cleared as long as RUNRES bit is cleared.
4.3.1.1 Reload functions
The 16-bit down counter can be reloaded 3 different ways:
At a zero overflow occurrence with the bit RELOAD
cleared: The counter is reloaded to FFFFh.
At a zero overflow occurrence with the bit
RELOAD set: The counter is reloaded with the value programmed in the RLCP register. For each
overflow, the transition between 0000h and the reload value (RLCP or FFFFh) is flagged through
the OVFFLG bit.
At an external event on pin CP1 or CP2 with the bit
RELOAD set: The counter is reloaded with the value programmed in the RLCP register.
As a consequence, the time between a timer reload and a zero overflow occurrence depends on
the value in RLCP when RELOAD bit is set. This
time is equal to (RLCP+1) x Psc x Tclk when
RELOAD bit is set, while it is 216 x Psc x Tclk
when RELOAD bit is cleared.
4.3.1.2 Compare functions
The value in the counter CT is continuously compared to 0000h and to the value programmed into
the Compare Register CMP. The comparison
range to 0000h and CMP is defined by using the
MASK register to select which bits are used,
therefore the comparisons performed are:
– MASK&CT ?= MASK&CMP.
– MASK&CT ?= 0000h.
When a matched comparison to 0000h or
MASK&CMP occurs, the flags ZEROFLG and
COMPFLG are respectively set.
By using MASK values reported inTable 16., the
MASK register works as counter frequency multiplier for the compare functions. In that case positive masked comparison occur with a period of
2(n+1) x Psc x Tclk where n is the position of the
most significant bit of MASK value.
Table 16. .Recommended Mask Values
Hexadecimal
FFFFh
7FFFh
3FFFh
1FFFh
0FFFh
...
0007h
0003h
0001h
1111
1111
1111
1111
1111
MSbit at 1
position,n
15
14
13
12
11
0111
0011
0001
2
1
0
Binary
1111
0111
0011
0001
0000
1111 1111
1111 1111
1111 1111
1111 1111
1111 1111
...
0000 0000 0000
0000 0000 0000
0000 0000 0000
Note: Writing 0000h in MASK gives a period equal
to two times the prescaled period Psc x Tclk.
Figure 24. . Flags Setting in Compare and Reload Functions
Counter
Value CT
CMP
0
FFFFh
or
RLCP
ZEROFLG
Software Reset
OVFFLG
Software Reset
COMPFLG
Software Reset
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ST62T35B/E35B
CENTRAL COUNTER (Cont’d)
4.3.1.3 Capture functions
Content of the counter CT can always be downloaded (captured) into the CP register at selectable event occurrence on pins CP1 and CP2, while
capture in RLCP is possible only when the bit
RELOAD is cleared.
Capture functions with RELOAD cleared are used
for period or pulse width measurements with input
CP2, or for phase measurements between two
signals on CP1 and CP2, with the counter in free
running mode. In these modes, counter values by
the two events occurence are stored into RLCP
and CP and the counter remains in free running
mode.
Capture functions with RELOAD set, are used for
same application purpose, but in that case, the
first event reloads the counter from RLCP while
the second event captures the counter content
into the CP register. Therefore, the counter is not
in free running mode for other functions since the
down counting start is initiated by either CP1, CP2
or RUNRES event according to RLDSEL1 and
RLDSEL2 bit.
4.3.2 SIGNAL GENERATION MODES
4.3.2.1 Output modes
Any positive
comparison
to 0000h or
MASK&CMP, and any overflow occurence can be
used to control the OVF or PWM output pins in
various modes defined by bits OVFMD, PWMPOL, PWMEN and PWMMD.
PWM pin output modes
MASK & CNT
= 0000h
MASK&CT=
MASK&CMP
PWMEN
PWMMD
PWMPOL
PWM pin
x
x
no
yes
no
yes
X
x
x
yes
no
yes
no
yes
0
X
0
0
0
1
1
1
1
1
X
0
0
0
0
1
1
0
0
1
1
X
1 Reset Set Set Reset Toggle
OVF pin output modes
Zero overflow (OVFFLG)
OVFMD
OVF pin
1
0
Set*
* The OVF pin is reset by clearing the flag OVFFLG.
4.3.2.2 Frequency and duty cycles on PWM
pins
In Set/Reset mode (PWMMD=0), the period on
the PWM pin is the time between two matched
masked comparison to 0000h, at which PWM pin
is set (PWMPOL=1) or reset (PWMPOL=0). As
long as no reload function from RLCP is performed (RELOAD bit cleared) and no mask is
used, this value is 216 x Psc x Tclk. If, on the contrary, reload function or a mask are used, the frequency is controlled through the RLCP and MASK
values (Figure 25.). The condition to reset (PWMPOL=1) or set back (PWMPOL=0) PWM pin is a
matched masked comparison to CMP. Given a
RLCP and MASK values within the Table 1, CMP
defines the duty cycle.
In Toggle mode (PWMMD=1), PWM pin changes
of state at each positive masked comparison to
CMP value. The frequency is half the frequency in
Set/Reset mode and the duty-cycle is always
50%.
4.3.2.3 Frequency and duty cycles on OVF pin
OVF pin activation is directed by the timer overflow occurence and therefore its frequency depends only of the downcounting time from the reload value to 0000h. This means its period is
equal to T= (RLCP+1) x Psc x Tclk in Set/Reset
mode and 2 x (RLCP+1) x Psc x Tclk in Toggle
mode.
Duty cycle is controlled in Set/Reset mode
(OVFMD cleared) by software, since OVF pin can
be reset only by clearing the OVFFLG bit. In toggle mode (OVFMD set), the duty cycle is always
50%.
Achievable periods on PWM pin
Mask value
FFFFh
Period in Set/Reset mode (PWMMD=0) (RLCP+1) x Psc x Tclk
Period in Toggle mode (PWMMD=1)
2 x (RLCP+1) x Psc x Tclk
Note: n is the position of the most significant bit of MASK value.
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1
1
Toggle
xxxxh
2 (n+1) x Psc x Tclk
2 x 2 (n+1) x Psc x Tclk
ST62T35B/E35B
Figure 25. . Mask Impact on the Compare Functions in PWM mode (PWMD=0, PWMPOL=1)
Counter
Bit 0...3
F
E
D
C
B
A
9
8
7
6
5
4
3
2
1
MASK
0007h
0003&000C = 0000h
0001h
F
24/fCLK
most
significant
“1” is bit 3
000Fh
0003h
0
0003&0007 = 0003&000F
23/fCLK
most
significant
“1” is bit 2
22/fCLK
most
significant
“1” is bit 1
21/fCLK
most
significant
“1” is bit 0
CMP = 000Fh
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ST62T35B/E35B
4.3.3 TIMINGS MEASUREMENT MODES
These modes are based on the capture of the
down counter content into either CP or RLCP registers. Some are used in conjunction with a synchronisation of the down counter by reload functions on external event on CPi pins or software
RUNRES setting, while other modes do not affect
the downcounting. As long as RELOAD bit is
cleared, the down counter remains in free running
mode.
RELOAD
1
0
Reload on CP1,CP2, RUNRES / Capture CP2
Capture CP1 / Capture CP2
4.3.3.1 Timing measurement with startup
control
Three startup conditions, selected by RLDSELi bit
can reload the counter from RLCP and initiate the
down counting when RELOAD bit is set. The first
mode is software controlled through the RUNRES
bit, while the two others are based on external event
on pins CP1 and CP2 with configurable polarities.
External event on CP2 pin (with configurable polarities) is used as strobe to launch the capture of
the CT counter into CP. When RELOAD bit is set,
RLCP cannot be used for capture, since it contains the reload value..
Finally, 3 different Reload/Capture sequences are
available:
– CP1 triggered restart mode with CP2 event detection.
– CP2 triggered restart mode with second CP2
event detection.
– Software triggered restart mode with CP2 event
detection.
CP1 triggered restart mode with CP2 event detection.
This mode is enabled for RLDSEL2=0 and
RLDSEL1=1.
External events on CPi pins are enabled as soon as
RUNRES bit is set, which lets the prescaler and the
down counter running. The next active edge on CP1
causes the counter to be loaded from RLCP, the
CP1FLG to be set and the downcounting startsfrom
RLCP value. Each following active edge on CP1 will
cause a reload of the counter. If CP1FLG is not reset before the next reload, the CP1ERR flag is set
at the same time as the counter is reloaded. Both
flags should then be cleared by software.
While the counter is counting, any active edge on
CP2 will capture the value of the counter at that instant into the CP Register and set the CP2FLG bit.
If CP2FLG is not cleared before the following CP2
event, the CP2ERR flag bit is set, and no new capture can be performed
Capturing is re-enabled by clearing both CP2FLG
and CP2ERR.
If a capture on CP2 and a reload on CP1 occur at the
same time, the capture of the counter to CP is made
first, and then the counter is reloaded from RLCP.
Figure 26. . CP1 Triggered Restart Mode with CP2 Event Detection
COUNTER
CT
0000h
0000h
RUNRES
Enable the Inputs
Software Reset
CP1
Disabled Reload and Start
Set CP1FLG
Reload
Set CP1ERR
Reload
Set CP1FLG
Disabled
CP2
Disabled
Capture CT into CP
Set CP2FLG
Set CP2ERR
Clear all Flags
First Capture in CP
Then Reload
Set CP1ERR, CP2FLG
Disabled
VR02007
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ST62T35B/E35B
TIMINGS MEASUREMENT MODES(Cont’d)
CP2 triggered restart mode with CP2 event detection.
This mode is enabled for RLDSEL2=1 and
RLDSEL1=0.
As long as RUNRES bit is set, an external event
on CP2 pin generates both, at first the capture into
CP, and then the reload from RLCP. Capture into
CP on CP2 event is enabled only if CP2FLG and
CP2ERR are cleared, otherwise only reload functions from RLCP are performed.
An external event on CP1 activates CP1FLG or
CP1ERR flags without any impact on the reload or
capture functions.
Note: After Reset, the first CP2 event will capture
the 0000h state of the counter into CP and then
will restart the counter after loading it from RLCP.
CP2FLG flag must always be cleared to execute
another capture into CP.
Software triggered restart mode with CP2
event detection.
This mode is enabled for RLDSEL2=0 and
RLDSEL1=0.
RUNRES bit setting initiates the reload and startup of the downcounting, while CP2 is used as
strobe source for the CT capture into CP register.
Figure 27. . CP2 Triggered Restart Mode with CP2 Event Detection
CP1
Set CP1FLG
Set CP1ERR
No action
CP2
Reload CT from RLCP
Set CP2ERR
First Capture CT into CP
Then Reload CT from RLCP
Set CP2FLG
Reload CT from RLCP
VR02007C
Figure 28. . Software Triggered Restart Mode with CP2 Event Detection
COUNTER
CT
0000h
0000h
RUNRES
Load Counter from RLCP and Startup
Software Reset
CP1
CP1 disabled
Set CP1FLG
Set CP1ERR
CP1 disabled
CP2
CP2 disabled
Capture CT into CP
Set CP2FLG
Set CP2ERR
VR02007D
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ST62T35B/E35B
TIMINGS MEASUREMENT MODES(Cont’d)
4.3.3.2 Timing measurement without startup
control
The down counter is in free running mode with
RUNRES bit set and RELOAD bit cleared. This
means counter automatically restarts from FFFFh
on zero overflow and signal generation on PWM
and OVF pins is not affected.
Two independent capture paths exist to CP and
RLCP, which are both Read only registers. CP1 is
the source (Configurable polarity) for a capture
into RLCP while CP2 is the source (Configurable
polarity) of a capture into CP.
Independently of CP2 signal, if CP1FLG and
CP1ERR are cleared, the first active edge on CP1
will trigger a capture into RLCP, triggering
CP1FLG. As long as CP1FLG has not been
cleared, a second following active edge will trig
CP1ERR without any capture into neither RLCP
nor CP.
Independently of CP1 signal, if CP2FLG and
CP2ERR are cleared, the first active edge on CP2
will trigger a capture into CP, triggering CP2FLG.
As long as CP2FLG has not been cleared, a sec-
ond following active edge will trig CP2ERR without
any capture into neither RLCP or CP.
4.3.4 INTERRUPT CAPABILITIES
The interrupt source latches of the ARTIMER16
are always enabled and set any time the interrupt
condition occurs.
The interrupt output is a logical OR of five logical
ANDs:
– INT = [(CP1FLG & CP1IEN)
– OR (CP2FLG & CP2IEN)
– OR(OVFFLG & OVFIEN)
– OR(COMPFLG & CMPIEN)
– OR (ZEROFLG & ZEROIEN)]
Thus, if any enable bit is 1, the interrupt output of
the ARTIMER16 goes high when the respective
flag is set. If no enable bit is 1, and one of the interrupt flags is set, the interrupt output remains 0,
but if the respective enable bit is set to 1 through a
write operation, the interrupt output will go high,
signalling the interrupt to the Core.
Figure 29. . Positive CP1 - to negative CP2-Edge Measurement C
( P1POL = 1, CP2POL = 0)
COUNTER
CP1
Capture into RLCP
Set CP1ERR
Set CP1FLG
CP2
Capture into CP
Set CP2FLG
Application Note:
Depending on polarity setting for CP1/CP2, and of
CP1/CP2 connections, phase, period and pulse
width measurements can be achieved. The total
independence between CP1 and CP2 captures allows phase detection by measuring which of
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47
Set CP2ERR
VR02006F
CP1FLG or CP2FLG is set at first following a reset
of these flags.
CP1=CP2
Yes
Yes
No
CP1POL=CP2POL
Yes
No
X
Measurement
Period
Pulse width
Phase
ST62T35B/E35B
4.3.5 CONTROL REGISTERS
Status Control Register 1 (SCR1)
Address: E8h - Read/Write/Clear only
7
PSC2
PSC1 RELOAD RUNRES OVFIEN OVFFLG OVFMD
Bit 0 = This bit is reserved and must be set to 0.
Status Control Register 2 (SCR2)
Address: E1h - Read/Write/Clear only
0
7
-
-
Bits 7 & 6 = PSC2..PSC1. Clock Prescaler. These
bits define the prescaler options for the prescaler
to the Counter Register according to the following
table.
PSC2
PSC1
0
0
0
1
1
1
0
1
Function
Clock Disabled (prescaler and counter
stopped
Prescale by 1
Prescale by 4
Prescale by 16
The Prescaler must be disabled (PSC2 = 0, PSC1
= 0) before a new prescaler factor is set if the
counter is running (after a hardware reset the
prescaler is automatically disabled).
To avoid inconsistencies in timing, the prescaler
factor should be set first, and then the counter
started.
Bit 5 = RELOAD. Reload enabled. When set this
bit enables reload from RLCP register into CT register. On the contrary, if RELOAD is cleared,
RLCP is used as target for capture from the counter CT register.
Bit 4 = RUNRES. Run/Reset. This bit enables the
RUN or RESET operation of the ARTIMER.
If 0, the counter CT is cleared to zero, and is
stopped. Setting this bit to 1 permits the startup of
the counter, and enables the synchronisation circuits for the timer inputs CP1 and CP2.
Bit 3 = OVFIEN. Overflow Int. Enable. The Overflow Interrupt is masked when this bit is 0.
Setting the bit to 1 enables the overflow flag to set
the ARTIMER interrupt.
Bit 2 = OVFFLG. When this bit is 0, no overflow
has occurred since the last clear of this bit. If the
bit is at 1, an overflow has occurred.
This bit cannot be set by program, only cleared.
Bit 1 = OVFMD. The Overflow Output mode is set
by this bit; when 0, the overflow output is run in set
mode (OVF will be set on the first overflow event,
and will be reset when OVFFLG is cleared). When
1 the overflow output is in toggle mode; OVF toggles its state on every overflow event (independent to the state of OVFFLG).
0
CP1ERR CP2ERR CP1IEN CP1FLG CP1POL RLDSEL2 RLDSEL1
Bit 7 = Reserved. Must be kept cleared.
Bit 6 = CP1ERR. CP1 Error Flag. This bit is set to
1 if a new CP1 event has taken place since
CP1FLG was set to signal an error condition, it is 0
if there has been no event.
It is recommended to clear CP1ERR at any time
that CP1FLG is cleared, as further CP1 events
cannot be recognised if CP1ERR is set. This bit
cannot bet set by write, only cleared.
Bit 5 = CP2ERR. CP1 Error Flag. This bit is set to
1 if a new CP2 event has taken place since
CP2FLG was set to signal an error condition, it is 0
if there has been no event.
It is recommended to clear CP2ERR at any time
that CP2FLG is cleared, as further CP2 events
cannot be recognised if CP2ERR is set. This bit
cannot bet set by write, only cleared.
Bit 4 = CP1IEN. CP1 Interrupt Enable. CP1 The
Capture 1 Interrupt is masked when this bit is 0.
Setting the bit to 1 enables the CP1 event flag
CP1FLG to set the ARTIMER interrupt.
Bit 3 = CP1FLG. CP1 Interrupt Flag. When this bit
is 0, no CP1 event has occurred since the last
clear of this bit. If the bit is at 1, a CP1 event has
occurred.
This bit cannot be set by program, only cleared.
Bit 2 = CP1POL. CP1 Edge Polarity Select.
CP1POL defines the polarity for triggering the
CP1 event.
A 0 defines the action on a falling edge on the CP1
input, a 1 on a rising edge.
Bit 1 & 0 = RLDSEL2..RLDSEL1. Reload Source
Select. These bits define the source for the reload
events; they do not affect the operation of the capture modes.
RLDSEL2 RLDSEL1
0
0
0
1
1
0
1
1
Function
Reload and startup triggered by
RUNRES
Reload triggered by every CP1
event
Reload triggered by every CP2
event
Reload disabled
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ST62T35B/E35B
CONTROL REGISTERS (Cont’d)
Status Control Register 3 (SCR3)
Address: E2h - Read/Write/Clear only
7
CP2POL CP2IEN CP2FLG CMPIEN
0
CMFLG
ZEROIEN ZEROFLG PWMMD
Bit 7 = CP2POL. CP2 Edge Polarity Select.
CP2POL defines the polarity for triggering the
CP2 event.
A 0 defines the action on a falling edge on the CP2
input, a 1 on a rising edge.
Bit 6 = CP2IEN. CP2 Interrupt Enable. The Capture 2 Interrupt is masked when this bit is 0. Setting the bit to 1 enables the CP2 event flag
CP2FLG to set the ARTIMER interrupt.
Bit 5 = CP2FLG. CP2 Interrupt Flag. When this bit
is 0, no CP2 event has occurred since the last
clear of this flag. If the bit is at 1, the first CP2
event and capture into CP has occurred.
This bit cannot be set by program, only cleared.
Bit 4 = CMPIEN. Compare Int. Enable. The Compare Interrupt is masked when this bit is 0.
Setting the bit to 1 enables the Compare flag
CMPFLG to set the ARTIMER interrupt.
Bit 3 = CMPFLG. Compare Flag. When this bit is
0, no Masked-Compare True event has occurred
since the last clear of this flag. If the bit is at 1, a
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Masked-Compare event has occurred.
This bit cannot be set by program, only cleared.
Bit 2 = ZEROIEN. Compare to Zero Int Enable.
The Masked-Counter Zero Interrupt is masked
when this bit is 0. Setting the bit to 1 enables the
ZEROFLG flag to set the ARTIMER interrupt.
Bit 1 = ZEROFLG. Compare to Zero Flag. When
this bit is 0, no Masked-Counter Zero event has
occurred since the last clear of this flag. If the bit is
at 1, a Masked-Counter Zero event has occurred
as the Masked Counter state equals 0 when running or on hold (not on Reset).
Bit 0 = PWMMD. PWM Output Mode Control. The
PWM Output mode is set by this bit; when 0, the
PWM output is run in set/reset mode (the PWM
output is set on a Masked-Counter Zero event and
is reset when on a Masked-Compare event).
When 1 the PWM output is in toggle mode; PWM
toggles its state on every Masked-Compare event.
Notes:
A Masked-Compare is the logical AND of the
Mask Register MASK with the Counter Register
CT, compared with the logical AND of the compare Register CMP: [(MASK & CT) =
(MASK&CMP)].
A Masked-Counter Zero is the logical AND of the
Mask Register MASK with the Counter Register
CT, compared with zero: [(MASK & CT) = 0000h]
ST62T35B/E35B
CONTROL REGISTERS (Cont’d)
Status Control Register 4 (SCR4)
Address: E3h - Read/Write/Clear only
7
Res. Res. Res. Res.
0
OVFPO
PWME
OVFEN PMPOL
L
N
Bit7- Bit4 = Reserved, set to 0.
Bit 3 = OVFPOL. Overflow Output Polarity. This bit
defines the polarity for the Overflow Output OVF.
When 0, OVF is set on every overflow event if enabled in Set mode (OVFEN = 1, OVFMD = 0). The
reset state of OVF is 0.
When 1, OVF is reset on every overflow event if
enabled in Set mode.
The reset state of OVF is 1.
Bit 2 = OVFEN. Overflow Output Enable. This bit
enables the Overflow output OVF. When 0 the
Overflow output is disabled: if OVFPOL = 0, the
state of OVF is 0, if OVFPOL = 1, the state of
OVF = 1.The Overflow Output is enabled when
this bit = 1, it must be set to use the OVF output.
Bit 1 = PWMPOL. PWM Output Polarity. This bit
defines the polarity for the PWM Output PWM.
When 0, PWM is set on every Masked-Counter
Zero event and is reset on a Masked-Compare if
enabled in Set/Reset mode (PWMEN = 1, PWMMD = 0).
The reset state of PWM pin is 0 When 1, OVF is
set on every Masked-Compare event and is reset
on a Masked-Counter Zero event if enabled in
Set/Reset mode (PWMEN = 1, PWMMD = 0).
The reset state of PWM is 1.
Bit 0 = PWMEN. PWM Output Enable. This bit enables the PWM output PWM. When 0 the PWM
output is disabled: if PWMPOL = 0, the state of
PWM is 0, if PWMPOL = 1, the state of PWM = 1.
The PWM Output is enabled when this bit = 1, it
must be set to use the PWM output.
Notes:
A Masked-Compare is the logical AND of the
Mask Register MASK with the Counter Register
CT, compared with the logical AND of the compare Register CMP: [(MASK & CT) =
(MASK&CMP)].
A Masked-Counter Zero is the logical AND of the
Mask Register MASK with the Counter Register
CT, compared with zero: [(MASK & CT) = 0000h].
4.3.6 16-BIT REGISTERS
Note: Care must be taken when using single-bit
instructions (RES/SET/INC/DEC) 16-bit registers
(RLCP, CP, CMP, MSK) since these instructions
imply a READ-MODIFY-WRITE operation on the
register. As the ST6 is based on a 8-bit architecture, to write a 16-bit register, the high byte must
be written first to an intermediate register (latch
register) and the whole 16-bit register is loaded at
the same time as the low byte is written. A WRITE
operation of the HIGH byte is performed on the intermediate register (latch register) but a READ operation of the HIGH byte is directly performed on
the 16-bit register (last loaded value). As a consequence, it is always mandatory to write the LOW
byte before any single-bit instruction on the HIGH
byte in order to load the value set in the intermediate register to the 16-bit register (refresh the 16-bit
register).
Example:
The following sequence is NOT GOOD:
ldi t16cmph, 055h
ldi t16cmpl, 000h
; t16cmp (16-bit register)=5500h
ldi t16cmph, 0AAh
; t16cmp (16-bit register)=5500h
inc t16cmph
; t16cmp (16-bit register)=5500h
ldi t16cmpl, 000h
; t16cmp (16-bit register)=5600h
; and NOT AB00h
The CORRECT sequence is:
ldi t16cmph, 055h
ldi t16cmpl, 000h
; t16cmp (16-bit register)=5500h
ldi t16cmph, 0AAh
; t16cmp (16-bit register)=5500h
ldi t16cmpl, 000h
; t16cmp (16-bit register)=AA00h
inc t16cmph
; t16cmp (16-bit register)=AA00h
ldi t16cmpl, 000h
;t16cmp (16-bit register)=AB00h
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ST62T35B/E35B
Reload/Capture Register High Byte (RLCP)
Address: E9h - Read/ (Write if RELOAD bit set)
D7-D0. These bits are the High byte (D15-D8) of
the 16-bit Reload/Capture Register.
Compare Register High Byte (CMP)
Address: EDh - Read/Write
D7-D0. These bits are the High byte (D15-D8) of
the 16-bit Compare Register.
Reload/Capture Register Low Byte (RLCP)
Address: EAh - Read/ (Write if RELOAD bit set)
D7-D0. These bits are the Low byte (D7-D0) of the
16-bit Reload/Capture Register.
Compare Register Low Byte (CMP)
Address: EEh - Read/Write
D7-D0. These bits are the Low byte (D7-D0) of the
16-bit Compare Register.
Capture Register High Byte (CP)
Address: EBh - Read Only
D7-D0. These bits are the High byte (D15-D8) of
the 16-bit Capture Register.
Mask Register High Byte (MASK)
Address: EFh - Read/Write
D7-D0. These bits are the High byte (D15-D8) of
the 16-bit Mask Register.
Capture Register Low Byte (CP)
Address: ECh - Read Only
D7-D0. These bits are the Low byte (D7-D0) of the
16-bit Capture Register.
Mask Register Low Byte (MASK)
Address: E0h - Read/Write
D7-D0. These bits are the Low byte (D7-D0) of the
16-bit Mask Register.
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ST62T35B/E35B
4.4 A/D CONVERTER (ADC)
The A/D converter peripheral is an 8-bit analog to
digital converter with analog inputs as alternate
I/O functions (the number of which is device dependent), offering 8-bit resolution with a selectable conversion time of 70us or 35µs (at an oscillator clock frequency of 8MHz).
The ADC converts the input voltage by a process
of successive approximations, using a clock frequency derived from the oscillator with a division
factor of 12 or 6. After Reset, division by 12 is
used by default to insure compatibility with other
members of the ST62 MCU family. With an oscillator clock frequency less than 1.2MHz, conversion accuracy is decreased.
Selection of the input pin is done by configuring
the related I/O line as an analog input via the Option and Data registers (refer to I/O ports description for additional information). Only one I/O line
must be configured as an analog input at any time.
The user must avoid any situation in which more
than one I/O pin is selected as an analog input simultaneously, to avoid device malfunction.
The ADC uses two registers in the data space: the
ADC data conversion register, ADR, which stores
the conversion result, and the ADC control register, ADCR, used to program the ADC functions.
A conversion is started by writing a “1” to the Start
bit (STA) in the ADC control register. This automatically clears (resets to “0”) the End Of Conversion Bit (EOC). When a conversion is complete,
the EOC bit is automatically set to “1”, in order to
flag that conversion is complete and that the data
in the ADC data conversion register is valid. Each
conversion has to be separately initiated by writing
to the STA bit.
The STA bit is continuously scanned so that, if the
user sets it to “1” while a previous conversion is in
progress, a new conversion is started before completing the previous one. The start bit (STA) is a
write only bit, any attempt to read it will show a logical “0”.
The A/D converter features a maskable interrupt
associated with the end of conversion. The interrupt request occurs when the EOC bit is set (i.e.
when a conversion is completed). The interrupt is
masked using the EAI (interrupt mask) bit in the
control register.
The power consumption of the device can be reduced by turning off the ADC peripheral. This is
done by setting the PDS bit in the ADC control
register to “0”. If PDS=“1”, the A/D is powered and
enabled for conversion. This bit must be set at
least one instruction before the beginning of the
conversion to allow stabilisation of the A/D converter. This action is also needed before entering
WAIT mode, since the A/D comparator is not automatically disabled in WAIT mode.
During Reset, any conversion in progress is
stopped, the control register is reset to 40h and
the ADC interrupt is masked (EAI=0).
Figure 30. ADC Block Diagram
Ain
CONVERTER
INTERRUPT
CLOCK
RESET
AVSS
AVDD
CONTROL REGISTER
RESULT REGISTER
8
8
CORE
CONTROL SIGNALS
CORE
VA00418
4.4.1 Application Notes
The A/D converter does not feature a sample and
hold circuit. The analog voltage to be measured
should therefore be stable during the entire conversion cycle. Voltage variation should not exceed
±1/2 LSB for the optimum conversion accuracy. A
low pass filter may be used at the analog input
pins to reduce input voltage variation during conversion.
When selected as an analog channel, the input pin
is internally connected to a capacitor Cad of typically 12pF. For maximum accuracy, this capacitor
must be fully charged at the beginning of conversion. In the worst case, conversion starts one instruction (6.5 µs) after the channel has been selected. In worst case conditions, the impedance,
ASI, of the analog voltage source is calculated using the following formula:
6.5µs = 9 x Cad x ASI
(capacitor charged to over 99.9%), i.e. 30 kΩ including a 50% guardband. ASI can be higher if
Cad has been charged for a longer period by adding instructions before the start of conversion
(adding more than 26 CPU cycles is pointless).
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ST62T35B/E35B
A/D CONVERTER (Cont’d)
Since the ADC is on the same chip as the microprocessor, the user should not switch heavily
loaded output signals during conversion, if high
precision is required. Such switching will affect the
supply voltages used as analog references.
The accuracy of the conversion depends on the
quality of the power supplies (VDD and VSS). The
user must take special care to ensure a well regulated reference voltage is present on the VDD and
VSS pins (power supply voltage variations must be
less than 5V/ms). This implies, in particular, that a
suitable decoupling capacitor is used at the VDD
pin.
The converter resolution is given by:
V DD – V S S
---------------------------256
The Input voltage (Ain) which is to be converted
must be constant for 1µs before conversion and
remain constant during conversion.
Conversion resolution can be improved if the power supply voltage (VDD) to the microcontroller is
lowered.
In order to optimise conversion resolution, the
user can configure the microcontroller in WAIT
mode, because this mode minimises noise disturbances and power supply variations due to output
switching. Nevertheless, the WAIT instruction
should be executed as soon as possible after the
beginning of the conversion, because execution of
the WAIT instruction may cause a small variation
of the VDD voltage. The negative effect of this variation is minimized at the beginning of the conversion when the converter is less sensitive, rather
than at the end of conversion, when the less significant bits are determined.
The best configuration, from an accuracy standpoint, is WAIT mode with the Timer stopped. Indeed, only the ADC peripheral and the oscillator
are then still working. The MCU must be woken up
from WAIT mode by the ADC interrupt at the end
of the conversion. It should be noted that waking
up the microcontroller could also be done using
the Timer interrupt, but in this case the Timer will
be working and the resulting noise could affect
conversion accuracy.
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A/D Converter Control Register (ADCR)
Address: 0D1h — Read/Write
7
EAI
0
EOC
STA
PDS
D3
CLSEL
D1
D0
Bit 7 = EAI: Enable A/D Interrupt. If this bit is set to
“1” the A/D interrupt is enabled, when EAI=0 the
interrupt is disabled.
Bit 6 = EOC: End of conversion. Read Only. This
read only bit indicates when a conversion has
been completed. This bit is automatically reset to
“0” when the STA bit is written. If the user is using
the interrupt option then this bit can be used as an
interrupt pending bit. Data in the data conversion
register are valid only when this bit is set to “1”.
Bit 5 = STA: Start of Conversion. Write Only. Writing a “1” to this bit will start a conversion on the selected channel and automatically reset to “0” the
EOC bit. If the bit is set again when a conversion is
in progress, the present conversion is stopped
and a new one will take place. This bit is write only, any attempt to read it will show a logical zero.
Bit 4 = PDS: Power Down Selection. This bit activates the A/D converter if set to “1”. Writing a “0” to
this bit will put the ADC in power down mode (idle
mode).
Bit 3 = Reserved. Must be kept cleared
Bit 2= CLSEL: Clock Selection. When set, the
ADC is driven by the MCU internal clock divided
by 6, and typical conversion time at 8MHz is 35µs.
When cleared (Reset state), MCU clock divided by
12 is used with a typical 70µs conversion time at
8MHz.
Bit 1-0: Reserved. Must be kept cleared.
A/D Converter Data Register (ADR)
Address: 0D0h — Read only
7
D7
0
D6
D5
D4
D3
D2
D1
D0
Bit 7-0 = D7-D0: 8 Bit A/D Conversion Result.
ST62T35B/E35B
4.5 U. A. R. T. (Universal Asynchronous Receiver/Transmitter)
The UART provides the basic hardware for asynchronous serial communication which, combined
with an appropriate software routine, gives a serial
interface providing communication with common
baud rates (up to 38,400 Baud with an 8MHz external oscillator) and flexible character formats.
Operating in Half-Duplex mode only, the UART
uses 11-bit characters comprising 1 start bit, 9 data
bits and 1 Stop bit. Parity is supported by software
only for transmit and for checking the received parity bit (bit 9). Transmitted data is sent directly, while
received data is buffered allowing further data
characters to be received while the data is being
read out of the receive buffer register. Data transmit has priority over data being received.
The UART is supplied with an MCU internal clock
that is also available in WAIT mode ofthe processor.
4.5.1 PORTS INTERFACING
RXD reception line and TXD emission line are
sharing the same external pins as two I/O lines.
Therefore, UART configuration requires to set
these two I/O lines through the relevant ports registers. The I/O line common with RXD line must be
defined as input mode (with or without pull-up)
while the I/O line common with TXD line must be
defined as output mode (Push-pull or open drain).
The transmitted data is inverted and can therefore
use a single transistor buffering stage. Defined as
input, the RXD line can be read at any time as an
I/O line during the UART operation. The TXD pin
follows I/O port registers value when UARTOE bit
is cleared, which means when no serial transmission is in progress. As a consequence, a permanent high level has to be written onto the I/O port
in order to achieve a proper stop condition on the
TXD line when no transmission is active.
Figure 31. UART Block Diagram
START
DETE CTOR
RXD1
UARTOE
DIN
DATA SHIFT
REGISTER
DOUT
TXD
1
MUX
D8 D7 D6 D5 D4 D3 D2 D1 D0
DR
TXD1
0
CONTROL LOGIC
TO CORE
WRITE
READ
RECEIVE BUFFE R
REGISTER
CONTROL REGISTER
BAUD RATE
D9
RX and TX
INTERRUPTS
PROGRAMMABLE
DIVIDER
fOSC
BAUD RATE x 8
VR02009
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ST62T35B/E35B
4.5.2 CLOCK GENERATION
The UART contains a built-in divider of the MCU
internal clock for most common Baud Rates as
shown in Table 18 . Other baud rate values can be
calculated from the chosen oscillator frequency divided by the Divisor value shown.
The divided clock provides a frequency that is 8
times the desired baud rate. This allows the Data
reception mechanism to provide a 2 to 1 majority
voting system to determine the logic state of the
asynchronous incoming serial logic bit by taking 3
timed samples within the 8 time states.
The bits not sampled provide a buffer to compensate for frequency offsets between sender and receiver.
4.5.3 DATA TRANSMISSION
Transmission is fixed to a format of one start bit,
nine data bits and one stop bit. The start and stop
bits are automatically generated by the UART.
The nine databits are under control of the user and
are flexible in use. Bits 0..7 are typically used as
data bits while bit 9 is typically used as parity, but
can also be a 9th data bit or an additional Stop bit.
As parity is not generated by the UART, it should
be calculated by program and inserted in the appropriate position of the data (i.e as bit 7 for 7-bit
data, with Bit 9 set to 1 giving two effective stop
bits or as the independent bit 9).
The character options are summarised in the following table.
Figure 32. Data Sampling Points
Figure 33. Character Format
Table 17. . Character Options
Start Bit
Start Bit
Start Bit
Start Bit
8
9
8
7
Data
Data
Data
Data
BIT
POSITION
2
3
4
SAMPLES
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5
6
7
1
2
8
START OF DATA
VR02010
Stop
Stop
Stop
Stop
STOP
BIT
D0 D1
1
1
1
2
2
Bit 9 remains in the state programmed for consecutive transmissions until changed by the user or
until a character is received when the state of this
bit is changed to that of the incoming bit 9. The
recommended procedure is thus to set the value
of this bit before transmission is started.
Transmission is started by writing to the Data Register (the Baud Rate and Bit 9 should be set before
this action). The UARTOE signal switches the output multiplexer to the UART output and a start bit
is sent (a 0 for one bit time) followed by the 8 data
values (lsb first) and the value of the Bit9 bit. The
output is then set to 1 for a period of one bit time to
generate a Stop bit, and then the UARTOE signal
returns the TXD1 line to its alternate I/O function.
The end of transmission is flagged by setting
TXMT to 1 and an interrupt is generated if enabled. The TXMT flag is reset by writing a 0 to the
bit position, it is also cleared automatically when a
new character is written to the Data Register.
TXMT can be set to 1 by software to generate a
software interrupt so care must be taken in manipulating the Control Register.
START
BIT
1 BIT
0
1 Software Parity
No Parity
No Parity
1 Software Parity
D7 D8
8
9
10
POSSIBLE
NEXT
CHARACTER
START
VR02012
ST62T35B/E35B
4.5.4 DATA RECEPTION
The UART continuously looks for a falling edge on
the input pin whenever a transmission is not active. Once an edge is detected it waits 1 bit time (8
states) to accommodate the Start bit, and then assembles the following serial data stream into the
data register. The data in the ninth bit position is
copied into Bit 9, replacing any previous value set
for transmission. After all 9 bits have been received, the Receiver waits for the duration of one
bit (for the Stop bit) and then transfers the received data into the buffer register, allowing a following character to be received. The interrupt flag
RXRDY is set to 1 as the data is transferred to the
buffer register and, if enabled, will generate an interrupt.
If a transmission is started during the course of a
reception, the transmission takes priority and the
reception is stopped to free the resources for the
transmission. This implies that a handshaking system must be implemented, as polling of the UART
to detect reception is not available.
Figure 34. .UART Data Output
4.5.5 INTERRUPT CAPABILITIES
Both reception and transmission processes can
induce interrupt to the core as defined in the interrupt section. These interrupts are enabled by setting TXIEN and RXIEN bit in the UARTCR register, and TXMT and RXRDY flags are set accordingly to the interrupt source.
4.5.6 REGISTERS
UART Data Register (UARTDR)
Address: D6h, Read/Write
7
D7
0
D6
D5
D4
D3
D2
D1
D0
Bit7-Bit0. UART data bits. A write to this register
loads the data into the transmit shift register and
triggers the start of transmission. In addition this
resets the transmit interrupt flag TXMT. A read of
this register returns the data from the Receive
buffer.
Warning. No Read/Write Instructions may be
used with this register as both transmit and receive share the same address
UARTOE
TXD
1
MUX
PORT DATA
OUTPUT
TXD1
0
VR02011
Table 18. . Baudrate Selection
BR2
BR2
BR0
fINT Division
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
6.656
3.328
1.664
832
416
256
208
Baud Rate
fINT = 8MHz
fINT = 4MHz
1200
2400
4800
9600
19200
31200
38400
Reserved
600
1200
2400
4800
9600
15600
19200
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ST62T35B/E35B
REGISTERS (Cont’d)
UART Control Register (UARTCR)
Address: D7h, Read/Write
7
RXRDY TXMT RXIEN TXIE N
0
BR2
BR1
BR0
DAT9
Bit 7 = RXRDY. Receiver Ready. This flag becomes active as soon as a complete byte has
been received and copied into the receive buffer.
It may be cleared by writing a zero to it. Writing a
one is possible. If the interrupt enable bit RXIEN is
set to one, a software interrupt will be generated.
Bit 6 = TXMT. Transmitter Empty. This flag becomes active as soon as a complete byte has
been sent. It may be cleared by writing a zero to it.
It is automatically cleared by the action of writing a
data value into the UART data register.
Bit 5 = RXIEN. Receive Interrupt Enable. When
this bit is set to 1, the receive interrupt is enabled.
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Writing to RXIEN does not affect the status of the
interrupt flag RXRDY.
Bit 4 = TXIEN. Transmit Interrupt Enable. When
this bit is set to 1, the transmit interrupt is enabled.
Writing to TXIEN does not affect the status of the
interrupt flag TXRDY.
Bit 3-1= BR2..BR0. Baudrate select. These bits
select the operating baud rate of the UART, depending on the frequency of fOSC. Care should
be taken not to change these bits during communication as writing to these bits has an immediate
effect.
Bit 0 = DAT9. Parity/Data Bit 9. This bit represents
the 9th bit of the data character that is received or
transmitted. A write to this bit sets the level for the
bit 9 to be transmitted, so it must always be set to
the correct level before transmission. If used as
parity, the value has first to be calculated by software. Reading this bit will return the 9th bit of the
received character.
ST62T35B/E35B
4.6 SERIAL PERIPHERAL INTERFACE (SPI)
The on-chip SPI is an optimized serial synchronous interface that supports a wide range of industry standard SPI specifications. The on-chip
SPI is controlled by small and simple user software to perform serial data exchange. The serial
shift clock can be implemented either by software
(using the bit-set and bit-reset instructions), with
the on-chip Timer 1 by externally connecting the
SPI clock pin to the timer pin or by directly applying an external clock to the Scl line.
The peripheral is composed by an 8-bit Data/shift
Register and a 4-bit binary counter while the Sin
pin is the serial shift input and Sout is the serial
shift output. These two lines can be tied together
to implement two wires protocols (I C-bus, etc).
When data is serialized, the MSB is the first bit.
Sin has to be programmed as input. For serial out-
put operation Sout has to be programmed as
open-drain output.
The SCL, Sin and Sout SPI clock and data signals
are connected to 3 I/O lines on the same external
pins. With these 3 lines, the SPI can operate in the
following operating modes: Software SPI, S-BUS,
I C-bus and as a standard serial I/O (clock, data,
enable). An interrupt request can be generated after eight clock pulses. Figure 35. shows the SPI
block diagram.
The SCL line clocks, on the falling edge, the shift
register and the counter. To allow SPI operation in
slave mode, the SCL pin must be programmed as
input and an external clock must be supplied to
this pin to drive the SPI peripheral.
In master mode, SCL is programmed as output, a
clock signal must be generated by software to set
and reset the port line.
Figure 35. SPI Block Diagram
SPI Interrupt Disable Register
Write
SPI Data Register
Read
CLK
RESET
SCL
I/O Port
Data Reg
Direction
Set Res
DIN
CP
Sin
Q4
RESET
4-Bit Counter
(Q4=High after Clock8)
Q4
I/O Port
Data Reg
Direction
Interrupt
Sout
I/O Port
MUX
CP
DIN
0
OPR Reg.
1 Data Reg
Direction
DOUT
8-Bit Data
Shift Register
Reset
Load
DOUT
Output
8-Bit Tristate Data I/O
Enable
D0............... .............D7
to Processor Data Bus
VR01504
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ST62T35B/E35B
SERIAL PERIPHERAL INTERFACE(Cont’d)
After 8 clock pulses (D7..D0) the output Q4 of the
4-bit binary counter becomes low, disabling the
clock from the counter and the data/shift register.
Q4 enables the clock to generate an interrupt on
the 8th clock falling edge as long as no reset of the
counter (processor write into the 8-bit data/shift
register) takes place. After a processor reset the
interrupt is disabled. The interrupt is active when
writing data in the shift register and desactivated
when writing any data in the SPI Interrupt Disable
register.
The generation of an interrupt to the Core provides information that new data is available (input
mode) or that transmission is completed (output
mode), allowing the Core to generate an acknowledge on the 9th clock pulse (I C-bus).
The interrupt is initiated by a high to low transition,
and therefore interrupt options must be set accordingly as defined in the interrupt section.
After power on reset, or after writing the data/shift
register, the counter is reset to zero and the clock
is enabled. In this condition the data shift register
is ready for reception. No start condition has to be
detected. Through the user software the Core may
pull down the Sin line (Acknowledge) and slow
down the SCL, as long as it is needed to carry out
data from the shift register.
I C-bus Master-Slave, Receiver-Transmitter
When pins Sin and Sout are externally connected
together it is possible to use the SPI as a receiver
as well as a transmitter. Through software routine
(by using bit-set and bit-reset on I/O line) a clock
can be generated allowing I C-bus to work in master mode.
When implementing an I C-bus protocol, the start
condition can be detected by setting the processor
into a wait for start condition by enabling the interrupt of the I/O port used for the Sin line. This frees
the processor from polling the Sin and SCL lines.
After the transmission/reception the processor
has to poll for the STOP condition.
In slave mode the user software can slow down
the SCL clock frequency by simply putting the
SCL I/O line in output open-drain mode and writing a zero into the corresponding data register bit.
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As it is possible to directly read the Sin pin directly
through the port register, the software can detect a
difference between internal data and external data
(master mode). Similar condition can be applied to
the clock.
Three (Four) Wire Serial Bus
It is possible to use a single general purpose I/O
pin (with the corresponding interrupt enabled) as a
chip enable pin. SCL acts as active or passive
clock pin, Sin as data in and Sout as data out (four
wire bus). Sin and Sout can be connected together externally to implement three wire bus.
Note:
When the SPI is not used, the three I/O lines (Sin,
SCL, Sout) can be used as normal I/O, with the
following limitation: bit Sout cannot be used in
open drain mode as this enables the shift register
output to the port.
It is recommended, in order to avoid spurious interrupts from the SPI, to disable the SPI interrupt
(the default state after reset) i.e. no write must be
made to the 8-bit shift register. An explicit interrupt
disable may be made in software by a dummy
write to the SPI interrupt disable register.
SPI Data/Shift Register
Address: DDh - Read/Write (SDSR)
7
D7
0
D6
D5
D4
D3
D2
D1
D0
A write into this register enables SPI Interrupt after
8 clock pulses.
SPI Interrupt Disable Register
Address: DCh - Read/Write (SIDR)
7
D7
0
D6
D5
D4
D3
D2
D1
D0
A dummy write to this register disables SPI Interrupt.
ST62T35B/E35B
5 SOFTWARE
5.1 ST6 ARCHITECTURE
The ST6 software has been designed to fully use
the hardware in the most efficient way possible
while keeping byte usage to a minimum; in short,
to provide byte efficient programming capability.
The ST6 core has the ability to set or clear any
register or RAM location bit of the Data space with
a single instruction. Furthermore, the program
may branch to a selected address depending on
the status of any bit of the Data space. The carry
bit is stored with the value of the bit when the SET
or RES instruction is processed.
5.2 ADDRESSING MODES
The ST6 core offers nine addressing modes,
which are described in the following paragraphs.
Three different address spaces are available: Program space, Data space, and Stack space. Program space contains the instructions which are to
be executed, plus the data for immediate mode instructions. Data space contains the Accumulator,
the X,Y,V and W registers, peripheral and Input/Output registers, the RAM locations and Data
ROM locations (for storage of tables and constants). Stack space contains six 12-bit RAM cells
used to stack the return addresses for subroutines
and interrupts.
Immediate. In the immediate addressing mode,
the operand of the instruction follows the opcode
location. As the operand is a ROM byte, the immediate addressing mode is used to access constants which do not change during program execution (e.g., a constant used to initialize a loop
counter).
Direct. In the direct addressing mode, the address
of the byte which is processed by the instruction is
stored in the location which follows the opcode.
Direct addressing allows the user to directly address the 256 bytes in Data Space memory with a
single two-byte instruction.
Short Direct. The core can address the four RAM
registers X,Y,V,W (locations 80h, 81h, 82h, 83h)
in the short-direct addressing mode. In this case,
the instruction is only one byte and the selection of
the location to be processed is contained in the
opcode. Short direct addressing is a subset of the
direct addressing mode. (Note that 80h and 81h
are also indirect registers).
Extended. In the extended addressing mode, the
12-bit address needed to define the instruction is
obtained by concatenating the four less significant
bits of the opcode with the byte following the opcode. The instructions (JP, CALL) which use the
extended addressing mode are able to branch to
any address of the 4K bytes Program space.
An extended addressing mode instruction is twobyte long.
Program Counter Relative. The relative addressing mode is only used in conditional branch
instructions. The instruction is used to perform a
test and, if the condition is true, a branch with a
span of -15 to +16 locations around the address of
the relative instruction. If the condition is not true,
the instruction which follows the relative instruction is executed. The relative addressing mode instruction is one-byte long. The opcode is obtained
in adding the three most significant bits which
characterize the kind of the test, one bit which determines whether the branch is a forward (when it
is 0) or backward (when it is 1) branch and the four
less significant bits which give the span of the
branch (0h to Fh) which must be added or subtracted to the address of the relative instruction to
obtain the address of the branch.
Bit Direct. In the bit direct addressing mode, the
bit to be set or cleared is part of the opcode, and
the byte following the opcode points to the address of the byte in which the specified bit must be
set or cleared. Thus, any bit in the 256 locations of
Data space memory can be set or cleared.
Bit Test & Branch. The bit test and branch addressing mode is a combination of direct addressing and relative addressing. The bit test and
branch instruction is three-byte long. The bit identification and the tested condition are included in
the opcode byte. The address of the byte to be
tested follows immediately the opcode in the Program space. The third byte is the jump displacement, which is in the range of -127 to +128. This
displacement can be determined using a label,
which is converted by the assembler.
Indirect. In the indirect addressing mode, the byte
processed by the register-indirect instruction is at
the address pointed by the content of one of the
indirect registers, X or Y (80h,81h). The indirect
register is selected by the bit 4 of the opcode. A
register indirect instruction is one byte long.
Inherent. In the inherent addressing mode, all the
information necessary to execute the instruction is
contained in the opcode. These instructions are
one byte long.
61/82
60
ST62T35B/E35B
5.3 INSTRUCTION SET
The ST6 core offers a set of 40 basic instructions
which, when combined with nine addressing
modes, yield 244 usable opcodes. They can be divided into six different types: load/store, arithmetic/logic, conditional branch, control instructions,
jump/call, and bit manipulation. The following paragraphs describe the different types.
All the instructions belonging to a given type are
presented in individual tables.
Load & Store. These instructions use one, two or
three bytes in relation with the addressing mode.
One operand is the Accumulator for LOAD and the
other operand is obtained from data memory using one of the addressing modes.
For Load Immediate one operand can be any of
the 256 data space bytes while the other is always
immediate data.
Table 19. Load & Store Instructions
Instruction
Addressing Mode
Bytes
Cycles
LD A, X
LD A, Y
Short Direct
Short Direct
1
1
4
4
LD A, V
LD A, W
LD X, A
LD Y, A
LD V, A
LD W, A
LD A, rr
LD rr, A
LD A, (X)
LD A, (Y)
LD (X), A
LD (Y), A
LDI A, #N
LDI rr, #N
Short Direct
Short Direct
Short Direct
Short Direct
Short Direct
Short Direct
Direct
Direct
Indirect
Indirect
Indirect
Indirect
Immediate
Immediate
1
1
1
1
1
1
2
2
1
1
1
1
2
3
4
4
4
4
4
4
4
4
4
4
4
4
4
4
Notes:
X,Y. Indirect Register Pointers, V & W Short Direct Registers
# . Immediate data (stored in ROM memory)
rr. Data space register
∆. Affected
* . Not Affected
62/82
61
Flags
Z
∆
∆
∆
∆
∆
∆
∆
∆
∆
∆
∆
∆
∆
∆
∆
*
C
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
ST62T35B/E35B
INSTRUCTION SET (Cont’d)
Arithmetic and Logic. These instructions are
used to perform the arithmetic calculations and
logic operations. In AND, ADD, CP, SUB instructions one operand is always the accumulator while
the other can be either a data space memory con-
tent or an immediate value in relation with the addressing mode. In CLR, DEC, INC instructions the
operand can be any of the 256 data space addresses. In COM, RLC, SLA the operand is always the accumulator.
Table 20. Arithmetic & Logic Instructions
Instruction
ADD A, (X)
ADD A, (Y)
ADD A, rr
ADDI A, #N
AND A, (X)
AND A, (Y)
AND A, rr
ANDI A, #N
CLR A
CLR r
COM A
CP A, (X)
CP A, (Y)
CP A, rr
CPI A, #N
DEC X
DEC Y
DEC V
DEC W
DEC A
DEC rr
DEC (X)
DEC (Y)
INC X
INC Y
INC V
INC W
INC A
INC rr
INC (X)
INC (Y)
RLC A
SLA A
SUB A, (X)
SUB A, (Y)
SUB A, rr
SUBI A, #N
Addressing Mode
Indirect
Indirect
Direct
Immediate
Indirect
Indirect
Direct
Immediate
Short Direct
Direct
Inherent
Indirect
Indirect
Direct
Immediate
Short Direct
Short Direct
Short Direct
Short Direct
Direct
Direct
Indirect
Indirect
Short Direct
Short Direct
Short Direct
Short Direct
Direct
Direct
Indirect
Indirect
Inherent
Inherent
Indirect
Indirect
Direct
Immediate
Bytes
Cycles
1
1
2
2
1
1
2
2
2
3
1
1
1
2
2
1
1
1
1
2
2
1
1
1
1
1
1
2
2
1
1
1
2
1
1
2
2
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
Flags
Z
∆
∆
∆
∆
∆
∆
∆
∆
∆
*
C
∆
∆
∆
∆
∆
∆
∆
∆
∆
*
∆
∆
∆
∆
∆
∆
∆
∆
∆
∆
∆
∆
∆
∆
∆
∆
∆
∆
∆
∆
∆
∆
∆
∆
∆
∆
∆
∆
∆
∆
∆
∆
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
∆
∆
∆
∆
∆
∆
Notes:
X,Y.Indirect Register Pointers, V & W Short Direct RegistersD. Affected
# . Immediate data (stored in ROM memory)* . Not Affected
rr. Data space register
63/82
62
ST62T35B/E35B
INSTRUCTION SET (Cont’d)
Conditional Branch. The branch instructions
achieve a branch in the program when the selected condition is met.
Control Instructions. The control instructions
control the MCU operations during program execution.
Bit Manipulation Instructions. These instructions can handle any bit in data space memory.
One group either sets or clears. The other group
(see Conditional Branch) performs the bit test
branch operations.
Table 21. Conditional Branch Instructions
Jump and Call. These two instructions are used
to perform long (12-bit) jumps or subroutines call
inside the whole program space.
Instruction
JRC e
JRNC e
JRZ e
JRNZ e
JRR b, rr, ee
JRS b, rr, ee
Branch If
C=1
C=0
Z=1
Z=0
Bit = 0
Bit = 1
Bytes
Cycles
1
1
1
1
3
3
2
2
2
2
5
5
Notes:
b.
3-bit address
e.
5 bit signed displacement in the range -15 to +16<F128M>
ee. 8 bit signed displacement in the range -126 to +129
Flags
Z
*
*
*
*
*
*
C
*
*
*
*
∆
∆
rr. Data space register
∆ . Affected. The tested bit is shifted into carry.
* . Not Affected
Table 22. Bit Manipulation Instructions
Instruction
SET b,rr
RES b,rr
Addressing Mode
Bit Direct
Bit Direct
Bytes
Cycles
2
2
4
4
Notes:
b.
3-bit address;
rr. Data space register;
Flags
Z
*
*
C
*
*
* . Not<M> Affected
Table 23. Control Instructions
Instruction
NOP
RET
RETI
STOP (1)
WAIT
Addressing Mode
Inherent
Inherent
Inherent
Inherent
Inherent
Bytes
Cycles
1
1
1
1
1
2
2
2
2
2
Flags
Z
*
*
∆
*
*
C
*
*
∆
*
*
Notes:
1.
This instruction is deactivated<N>and a WAI T is automatically executed instead of a STOP if the watchdog function is selected.
∆ . Affected
*.
Not Affected
Table 24. Jump & Call Instructions
Instruction
CALL abc
JP abc
Notes:
abc. 12-bit address;
* . Not Affected
64/82
63
Addressing Mode
Extended
Extended
Bytes
Cycles
2
2
4
4
Flags
Z
C
*
*
*
*
ST62T35B/E35B
Opcode Map Summary.The following table contains an opcode map for the instructions used by the ST6
LOW
0
0000
HI
0
0000
1
0001
2
0010
3
0011
4
0100
5
0101
6
0110
7
0111
8
1000
9
1001
A
1010
B
1011
C
1100
D
1101
E
1110
F
1111
2
1
2
1
2
1
2
1
2
1
2
1
2
1
2
1
2
1
2
1
2
1
2
1
2
1
2
1
2
1
2
1
JRNZ
e
pcr
JRNZ
e
pcr
JRNZ
e
pcr
JRNZ
e
pcr
JRNZ
e
pcr
JRNZ
e
pcr
JRNZ
e
pcr
JRNZ
e
pcr
JRNZ
e
pcr
RNZ
e
pcr
JRNZ
e
pcr
JRNZ
e
pcr
JRNZ
e
pcr
JRNZ
e
pcr
JRNZ
e
pcr
JRNZ
e
pcr
1
0001
4
2
4
2
4
2
4
2
4
2
4
2
4
2
4
2
4
2
4
2
4
2
4
2
4
2
4
2
4
2
4
2
CALL
abc
ext
CALL
abc
ext
CALL
abc
ext
CALL
abc
ext
CALL
abc
ext
CALL
abc
ext
CALL
abc
ext
CALL
abc
ext
CALL
abc
ext
CALL
abc
ext
CALL
abc
ext
CALL
abc
ext
CALL
abc
ext
CALL
abc
ext
CALL
abc
ext
CALL
abc
ext
Abbreviation s for Addressing Modes:
dir
Direct
sd
Short Direct
imm Immediate
inh
Inherent
ext
Extended
b.d
Bit Direct
bt
Bit Test
pcr
Program Counter Relative
ind
Indirect
2
0010
2
1
2
1
2
1
2
1
2
1
2
1
2
1
2
1
2
1
2
1
2
1
2
1
2
1
2
1
2
1
2
1
JRNC
e
pcr
JRNC
e
pcr
JRNC
e
pcr
JRNC
e
pcr
JRNC
e
pcr
JRNC
e
pcr
JRNC
e
pcr
JRNC
e
pcr
JRNC
e
pcr
JRNC
e
pcr
JRNC
e
pcr
JRNC
e
pcr
JRNC
e
pcr
JRNC
e
pcr
JRNC
e
pcr
JRNC
e
pcr
3
0011
5
3
5
3
5
3
5
3
5
3
5
3
5
3
5
3
5
3
5
3
5
3
5
3
5
3
5
3
5
3
5
3
JRR
b0,rr,ee
bt
JRS
b0,rr,ee
bt
JRR
b4,rr,ee
bt
JRS
b4,rr,ee
bt
JRR
b2,rr,ee
bt
JRS
b2,rr,ee
bt
JRR
b6,rr,ee
bt
JRS
b6,rr,ee
bt
JRR
b1,rr,ee
bt
JRS
b1,rr,ee
bt
JRR
b5,rr,ee
bt
JRS
b5,rr,ee
bt
JRR
b3,rr,ee
bt
JRS
b3,rr,ee
bt
JRR
b7,rr,ee
bt
JRS
b7,rr,ee
bt
4
0100
2
5
0101
6
0110
JRZ
2
e
1
2
#
pcr
JRZ 4
e
1
2
e
x
e
sd 1
2
#
sd 1
2
#
pcr
JRZ 4
e
1
2
e
y
e
1
2
sd 1
2
#
e
sd 1
2
#
pcr
JRZ 4
e
1
2
1
2
sd 1
2
e
1
2
a,v
e
sd 1
2
#
pcr
JRZ 4
e
1
2
e
w
e
1
Legend:
#
Indicates Illegal Instructions
e
5 Bit Displacement
b
3 Bit Address
rr
1byte dataspace address
nn
1 byte immediate data
abc
12 bit address
ee
8 bit Displacement
prc 1
JRC 4
e
sd 1
2
#
pcr
JRZ 4
e
prc 2
JRC 4
1
INC 2
pcr 1
JRZ
1
2
prc 1
JRC 4
e
pcr 1
JRZ
1
2
prc
JRC 4
1
LD 2
prc 2
JRC 4
e
1
LD 2
a,w
pcr 1
prc 1
JRC
e
sd 1
Cycle
AND
a,(x)
ind
ANDI
a,nn
imm
SUB
a,(x)
ind
SUBI
a,nn
imm
DEC
(x)
ind
2
1
0001
2
0010
3
0011
4
0100
5
0101
6
0110
8
1000
9
1001
A
1010
B
1011
C
1100
D
1101
E
1110
#
F
1111
JRC
Mnemonic
prc
Operand
Bytes
ind
#
e
pcr
JRZ 4
LD
prc 1
JRC
0
0000
7
0111
(x),a
e
#
a,nn
imm
CP
a,(x)
ind
CPI
a,nn
imm
ADD
a,(x)
ind
ADDI
a,nn
imm
INC
(x)
ind
prc
JRC 4
1
INC 2
pcr 1
JRZ
ind
LDI
#
e
v
e
prc 1
JRC
e
pcr 1
JRZ
1
2
prc 2
JRC 4
1
LD 2
a,y
e
prc 1
JRC 4
e
pcr
JRZ 4
e
prc 2
JRC 4
1
INC 2
pcr 1
JRZ
1
2
prc 1
JRC 4
e
pcr 1
JRZ
e
prc 2
JRC 4
1
LD 2
a,x
1
2
a,(x)
e
pcr
JRZ 4
HI
LD
prc 1
JRC 4
e
pcr 1
JRZ
1
2
e
1
2
JRC 4
1
INC 2
LOW
7
0111
e
1
prc
Addressing Mode
65/82
64
ST62T35B/E35B
Opcode Map Summary(Continued)
LOW
8
1000
HI
0
0000
1
0001
2
0010
3
0011
4
0100
5
0101
6
0110
7
0111
8
1000
9
1001
A
1010
B
1011
C
1100
D
1101
E
1110
F
1111
2
1
2
1
2
1
2
1
2
1
2
1
2
1
2
1
2
1
2
1
2
1
2
1
2
1
2
1
2
1
2
1
JRNZ
e
pcr
JRNZ
e
pcr
JRNZ
e
pcr
JRNZ
e
pcr
JRNZ
e
pcr
JRNZ
e
pcr
JRNZ
e
pcr
JRNZ
e
pcr
JRNZ
e
pcr
RNZ
e
pcr
JRNZ
e
pcr
JRNZ
e
pcr
JRNZ
e
pcr
JRNZ
e
pcr
JRNZ
e
pcr
JRNZ
e
pcr
9
1001
4
A
1010
JP 2
abc
2
4
ext 1
JP 2
abc
2
4
ext 1
JP 2
abc
2
4
ext 1
JP 2
abc
2
4
ext 1
JP 2
abc
2
4
ext 1
JP 2
abc
2
4
ext 1
JP 2
abc
2
4
ext 1
JP 2
abc
2
4
ext 1
JP 2
abc
2
4
ext 1
JP 2
abc
2
4
ext 1
JP 2
abc
2
4
ext 1
JP 2
abc
2
4
ext 1
JP 2
abc
2
4
ext 1
JP 2
abc
2
4
ext 1
JP 2
abc
2
4
ext 1
JP 2
abc
2
ext 1
Abbreviation s for Addressing Modes:
dir
Direct
sd
Short Direct
imm Immediate
inh
Inherent
ext
Extended
b.d
Bit Direct
bt
Bit Test
pcr
Program Counter Relative
ind
Indirect
66/82
65
JRNC
e
pcr
JRNC
e
pcr
JRNC
e
pcr
JRNC
e
pcr
JRNC
e
pcr
JRNC
e
pcr
JRNC
e
pcr
JRNC
e
pcr
JRNC
e
pcr
JRNC
e
pcr
JRNC
e
pcr
JRNC
e
pcr
JRNC
e
pcr
JRNC
e
pcr
JRNC
e
pcr
JRNC
e
pcr
B
1011
4
2
4
2
4
2
4
2
4
2
4
2
4
2
4
2
4
2
4
2
4
2
4
2
4
2
4
2
4
2
4
2
RES
b0,rr
b.d
SET
b0,rr
b.d
RES
b4,rr
b.d
SET
b4,rr
b.d
RES
b2,rr
b.d
SET
b2,rr
b.d
RES
b6,rr
b.d
SET
b6,rr
b.d
RES
b1,rr
b.d
SET
b1,rr
b.d
RES
b5,rr
b.d
SET
b5,rr
b.d
RES
b3,rr
b.d
SET
b3,rr
b.d
RES
b7,rr
b.d
SET
b7,rr
b.d
C
1100
2
D
1101
JRZ 4
e
1
2
pcr 3
JRZ 4
e
1
2
pcr 1
JRZ 4
e
1
2
e
1
2
E
1110
LDI 2
rr,nn
imm
DEC
x
sd
COM
a
pcr
JRZ 4
e
1
2
pcr 1
JRZ 2
sd 1
RETI 2
pcr 1
JRZ 4
inh 1
DEC 2
y
pcr 1
JRZ 2
sd 1
STOP 2
pcr 1
JRZ 4
inh 1
LD 2
1
2
y,a
e
#
e
v
e
pcr 1
JRZ 2
sd 1
RET 2
pcr 1
JRZ 4
inh 1
DEC 2
2
JRC
prc 1
JRC 4
prc 2
JRC 4
e
w
prc 1
JRC 4
e
pcr 1
JRZ 2
sd 1
WAIT 2
pcr 1
JRZ 4
inh 1
LD 2
prc 2
JRC 4
e
e
Legend:
#
Indicates Illegal Instructions
e
5 Bit Displacement
b
3 Bit Address
rr
1byte dataspace address
nn
1 byte immediate data
abc
12 bit address
ee
8 bit Displacement
prc 2
prc 2
JRC 4
e
e
1
prc 1
JRC 4
e
v,a
e
1
2
prc 2
JRC 4
inh 1
LD 2
e
1
2
prc 1
JRC 4
sd 1
RCL 2
a
e
1
2
prc 2
JRC 4
e
pcr 1
JRZ 4
1
2
prc 1
JRC 4
1
DEC 2
pcr 1
JRZ 4
1
2
dir
ADD
a,(y)
ind
ADD
a,rr
dir
INC
(y)
ind
INC
rr
dir
LD
(y),a
ind
LD
rr,a
dir
AND
a,(y)
ind
AND
a,rr
dir
SUB
a,(y)
ind
SUB
a,rr
dir
DEC
(y)
ind
DEC
rr
dir
e
pcr
JRZ 4
1
2
prc 2
JRC 4
sd 1
2
w,a
pcr 1
prc 1
JRC 4
e
sd 1
Cycle
Operand
Bytes
Addressing Mode
ind
CP
a,rr
e
pcr 1
JRZ
1
2
a,(y)
e
e
dir
CP
prc 1
JRC 4
e
e
1
2
e
e
e
ind
LD
a,rr
e
e
1
2
a,(y)
prc 2
JRC 4
1
LD 2
HI
LD
prc 1
JRC 4
e
x,a
1
2
JRC 4
1
2
LOW
F
1111
e
1
prc
0
0000
1
0001
2
0010
3
0011
4
0100
5
0101
6
0110
7
0111
8
1000
9
1001
A
1010
B
1011
C
1100
D
1101
E
1110
F
1111
Mnemonic
ST62T35B/E35B
6 ELECTRICAL CHARACTERISTICS
6.1 ABSOLUTE MAXIMUM RATINGS
This product contains devices to protect the inputs
against damage due to high static voltages, however it is advisable to take normal precaution to
avoid application of any voltage higher than the
specified maximum rated voltages.
For proper operation it is recommended that VI
and VO be higher than VSS and lower than VDD.
Reliability is enhanced if unused inputs are connected to an appropriate logic voltage level (VDD
or VSS).
Symbol
VDD
Parameter
Supply Voltage
Power Considerations.The average chip-junction temperature, Tj, in Celsius can be obtained
from:
Tj=TA + PD x RthJA
Where:TA = Ambient Temperature.
RthJA =Package thermal resistance(junction-to ambient).
PD = Pint + Pport.
Pint =IDD x VDD (chip internal power).
Pport =Port power dissipation (determined
by the user).
Value
Unit
-0.3 to 7.0
V
(1)
VI
Input Voltage
VSS - 0.3 to VDD + 0.3
V
VO
Output Voltage
V
IO
Current Drain per Pin Excluding VDD, V SS
VSS - 0.3 to VDD + 0.3(1)
±10
mA
50
mA
50
mA
IVDD
IVSS
Total Current into VDD (source)
Total Current out of VSS (sink)
Tj
Junction Temperature
150
°C
TSTG
Storage Temperature
-60 to 150
°C
Notes:
- 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 at these conditions is not implied. Exposure to maximum rating conditions for extended period s may
affect device reliability.
- (1) Within these limits, clamping diodes are guarantee to be not conductive. Voltages outside these limits are authorised as long as injection
current is kept within the specification.
67/82
66
ST62T35B/E35B
6.2 RECOMMENDED OPERATING CONDITIONS
Symbol
Parameter
Value
Test Condition s
Min.
Typ.
Max.
Unit
TA
Operating Temperature
6 Suffix Version
1 Suffix Version
3 Suffix Version
-40
0
-40
85
70
125
°C
VDD
Operating Supply Voltage
fOSC = 2MHz
fosc= 8MHz
3.0
4.5
6.0
6.0
V
fOSC
Oscillator Frequency 2)
VDD = 3V
VDD = 4.5V, 1 & 6 Suffix
VDD = 4.5V, 3 Suffix
0
0
0
4.0
8.0
4.0
MHz
fOSG
Internal Frequency with OSG
enable 2)
VDD = 3V
VDD = 4.5V
2
4
fOSC
fOSC
MHz
IINJ+
Pin Injection Current (positive)
VDD = 4.5 to 5.5V
+5
mA
IINJ-
Pin Injection Current (negative) VDD = 4.5 to 5.5V
-5
mA
Notes:
1. Care must be taken in case of negative current injection, where adapted impedance must be respected on analog sources to not affect
the A/D conversion. For a -1mA injection, a maximum 10 KΩ is recommended.
2. An oscillator frequency above 1MHz is recommended for reliable A/D results.
Figure 36. Maximum Operating FREQUENCY (Fmax) Versus SUPPLY VOLTAGE (V
DD)
Maximum FREQUE NCY (MHz)
8
FUNCTION ALITY IS NOT
1 & 6 Suffix Version
GUARANTEED IN
7
THIS AREA
6
5
3 Suffix Version
4
3
fOSG Min
2
1
2.5
3
3.5
4
4.5
5
5.5
6
SUPPLY VOLTAGE (VDD)
The shaded area is outside the recommended operating range; device functionality is not guaranteed under these conditions.
68/82
67
ST62T35B/E35B
6.3 DC ELECTRICAL CHARACTERISTICS
(TA = -40 to +125°C unless otherwise specified)
Symbol
VIL
VIH
VHys
Parameter
Test Cond itions
Input Low Level Voltage
All Input pins
Input High Level Voltage
All Input pins
Hysteresis Voltage (1)
All Input pins
Value
Min.
Typ.
VDD x 0.3
VDD= 5V
VDD= 3V
VOH
R PU
IIL
IIH
IDD
VDD= 5.0V; IOL = +10µA
VDD= 5.0V; IOL = + 3mA
VDD= 5.0V; IOL = +10µA
Low Level Output Voltage
VDD= 5.0V; IOL = +7mA
20 mA Sink I/O pins
VDD= 5.0V; IOL = +15mA
High Level Output Voltage VDD= 5.0V; IOL = -10µA
All Output pins
VDD= 5.0V; IOL = -3.0mA
All Input pins
Pull-up Resistance
RESET pin
Input Leakage Current
VIN = VSS (No Pull-Up configured)
All Input pins but RESET VIN = VDD
Input Leakage Current
VIN = VSS
RESET pin
VIN = VDD
Supply Current in RESET VRESET=VSS
Mode
fOSC=8MHz
Supply Current in
VDD=5.0V fINT=8MHz, TA < 85°C
RUN Mode (2)
Supply Current in WAIT
VDD=5.0V fINT=8MHz, TA < 85°C
Mode (3)
Supply Current in STOP
ILOAD=0mA
Mode (3)
VDD=5.0V
Unit
V
VDD x 0.7
V
0.2
0.2
V
Low Level Output Voltage
All Output pins
VOL
Max.
0.1
0.8
0.1
0.8
1.3
4.9
3.5
40
150
-8
V
V
100
350
200
900
0.1
1.0
-16
-30
10
ΚΩ
µA
7
mA
7
mA
2
mA
20
µA
Notes:
(1) Hysteresis voltage between switching levels
(2) All peripherals running
(3) All peripherals in stand-by
DC ELECTRICAL CHARACTERISTICS (cont’d)
(TA = -40 to +85°C unless otherwise specified)
Symbol
Parameter
Test Cond itions
Min.
Low Level Output Voltage
All Output pins
VOL
VOH
IDD
VDD= 5.0V; IOL = +10µA
VDD= 5.0V; IOL = + 5mA
VDD= 5.0V; IOL = +10µA
Low Level Output Voltage
VDD= 5.0V; IOL = +10mA
20 mA Sink I/O pins
VDD= 5.0V; IOL = +20mA
High Level Output Voltage VDD= 5.0V; IOL = -10µA
All Output pins
VDD= 5.0V; IOL = -5.0mA
Supply Current in STOP
ILOAD=0mA
Mode (3)
VDD=5.0V
Value
Typ.
Max.
0.1
0.8
0.1
0.8
1.3
4.9
3.5
Unit
V
V
10
µA
69/82
68
ST62T35B/E35B
6.4 AC ELECTRICAL CHARACTERISTICS
(TA = -40 to +125°C unless otherwise specified)
Symbol
Parameter
Value
Test Conditions
Min.
Typ.
Unit
Max.
tREC
Supply Recovery Time (1)
100
ms
TWR
Minimum Pulse Width (VDD = 5V)
RESET pin
NMI pin
100
100
ns
TWEE
EEPROM Write Time
TA = 25°C
TA = 85°C
TA = 125°C
5
10
20
10
20
30
Endurance EEPROM WRITE/ERASE Cycle
QA L OT Acceptance
Retention
EEPROM Data Retention
TA = 55°C
Input Capacitance
All Inputs Pins
10
pF
Output Capacitance
All Outputs Pins
10
pF
C IN
COUT
300,000 1 million
ms
cycles
10
years
Notes:
1. Period for which VDD has to be connected at 0V to allow internal Reset function at next power-up.
6.5 A/D CONVERTER CHARACTERISTICS
(TA = -40 to +125°C unless otherwise specified)
Symbol
Res
ATOT
tC
Parameter
Total Accuracy
(1) (2)
Conversion Time
Zero Input Reading
FSR
Full Scale Reading
AC IN
Min.
Resolution
ZIR
AD I
Test Condit ions
fOSC > 1.2MHz
fOSC > 32kHz
fOSC = 8MHz, TA < 85°C
fOSC = 4MHz
Conversion result when
VIN = VSS
Conversion result when
VIN = VDD
69
Max.
70
140
LSB
µs
00
Analog Input Current During
VDD= 4.5V
Conversion
Analog Input Capacitance
Unit
Bit
±2
±4
Notes:
1. Noise at AVDD, AVSS <10mV
2. Wit h oscillator frequencies less than 1MHz, the A/D Converter accuracy is decreased.
70/82
Value
Typ.
8
Hex
2
FF
Hex
1.0
µA
5
pF
ST62T35B/E35B
6.6 TIMER CHARACTERISTICS
(TA = -40 to +125°C unless otherwise specified)
Symbol
Parameter
f IN
Input Frequency on TIMER Pin
tW
Pulse Width at TIMER Pin
Test Condi tions
Value
Typ.
Min.
Max.
Unit
MHz
VDD = 3.0V
VDD >4.5V
µs
ns
1
125
6.7 .SPI CHARACTERISTICS
(TA = -40 to +125°C unless otherwise specified)
Symbol
Parameter
Test Conditions
FCL
tSU
th
Clock Frequency
Set-up Time
Hold Time
Applied on Scl
Applied on Sin
Applied onSin
Min.
Value
Typ.
Unit
Max.
1
MHz
ns
ns
50
100
6.8 ARTIMER16 ELECTRICAL CHARACTERISTICS
(TA = -40 to +125°C unless otherwise specified)
Symbol
Parameter
fIN
Input Frequency on CP1, CP2 Pins
tW
Pulse Width at CP1, CP2 Pins
Test Condit ions
Min
Value
Typ
Max
Unit
MHz
VDD = 3.0V
VDD >4.5V
1
125
µs
ns
71/82
70
ST62T35B/E35B
7 GENERAL INFORMATION
7.1 PACKAGE MECHANICAL DATA
Figure 37. 52-Pin Plastic Quad Flat Package
Dim
mm
Min
A
Min
Typ Max
3.40
0.134
A1
0.25
A2
2.55 2.80 3.05 0.100 0.110 0.120
B
0.35
0.50 0.014
0.020
C
0.13
0.23 0.005
0.009
D
16.95 17.20 17.45 0.667 0.677 0.687
D1
13.90 14.00 14.10 0.547 0.551 0.555
D3
0.010
12.00
0.472
E
16.95 17.20 17.45 0.667 0.677 0.687
E1
13.90 14.00 14.10 0.547 0.551 0.555
E3
12.00
e
1.00
K
L
0°
0.472
0.039
7°
0°
7°
0.65 0.80 0.95 0.026 0.031 0.037
L1
PQFP52
inches
Typ Max
1.60
0.063
M
Number of Pins
N
52
Figure 38. 52-Pin Ceramic Quad Flat Package with Window
Dim
mm
Min
A
A1
B
inches
Typ Max
Min
Typ Max
3.27
0.129
0.50
0.020
0.35 0.40 0.50 0.014 0.016 0.020
C
0.13 0.15 0.23 0.005 0.006 0.009
D
16.65 17.20 17.75 0.656 0.677 0.699
D1
13.57 13.97 14.37
D2
13.06 13.46 13.86 0.514 0.530 0.546
0.566
D3
12.00
e
1.00
0.039
G
12.70
0.500
G2
0.472
0.96
0.038
L
0.35 0.80
0.014 0.031
Ø
8.31
0.327
Number of Pins
CQFP052W
72/82
1
N
52
ST62T35B/E35B
THERMAL CHARACTERISTIC
Symbol
RthJA
Parameter
Test Conditions
Thermal Resistance
Value
Min.
Typ.
Max.
CQFP52W
70
QFP52
70
Unit
°C/W
7.2 ORDERING INFORMATION
Table 25. OTP/EPROM VERSION ORDERING INFORMATION
Sales Type
ST62E35BG1
ST62T35BQ6
ST62T35BQ3
Program
Memory (Bytes)
I/O
7948 (EPROM)
7948 (OTP)
36
Temperature Range
Package
0 to 70°C
CQFP52W
-40 to 85°C
-40 to 125°C
PQFP52
73/82
1
ST62T35B/E35B
Notes
74/82
1
ST62P35B
R
8-BIT FASTROM MCUs WITH A/D CONVERTER,
16-BIT AUTO-RELOAD TIMER, EEPROM, SPI AND UART
■
■
■
■
■
■
■
■
■
■
■
■
■
■
■
■
■
■
■
■
■
3.0 to 6.0V Supply Operating Range
8 MHz Maximum Clock Frequency
-40 to +125°C Operating Temperature Range
Run, Wait and Stop Modes
5 Interrupt Vectors
Look-up Table capability in Program Memory
Data Storage in Program Memory:
User selectable size
Data RAM: 192 bytes
Data EEPROM: 128 bytes
36 I/O pins, fully programmable as:
– Input with pull-up resistor
– Input without pull-up resistor
– Input with interrupt generation
– Open-drain or push-pull output
– Analog Input
12 I/O lines can sink up to 20mA to drive LEDs
or TRIACs directly
8-bit Timer/ Counter with 7-bit programmable
prescaler
16-bit
Auto-reload
Timer
with
7-bit
programmable prescaler (AR Timer)
Digital Watchdog
8-bit A/D Converter with 24 analog inputs
8-bit Synchronous Peripheral Interface (SPI)
8-bit Asynchronous Peripheral Interface
(UART)
On-chip Clock oscillator can be driven by Quartz
Crystal or Ceramic resonator
Oscillator Safe Guard
One external Non-Maskable Interrupt
ST623x-EMU2 Emulation and Development
System (connects to an MS-DOS PC via a
parallel port).
PQFP52
(See end of Datasheet for Ordering Information)
DEVICE SUMMARY
DEVICE
ST62P35B
ROM
(Bytes)
7948
I/O Pins
36
Rev. 2.3
March 1998
75/82
1
ST62P35B
1 GENERAL DESCRIPTION
1.1 INTRODUCTION
The ST62P35B is the Factory Advanced Service
Technique ROM (FASTROM) versions of
ST62T35B OTP devices.
They offer the same functionality as OTP devices,
selecting as FASTROM options the options defined in the programmable option byte of the OTP
version.
1.2 ORDERING INFORMATION
This listing refers exactly to the ROM contents and
options which will be used to produce the specified MCU. The listing is then returned to the customer who must thoroughly check, complete, sign
and return it to SGS-THOMSON. The signed listing forms a part of the contractual agreement for
the production of the specific customer MCU.
The SGS-THOMSON Sales Organization will be
pleased to provide detailed information on contractual points.
Table 1. ROM Memory Map for ST62P35B
The following section deals with the procedure for
transfer of customer codes to SGS-THOMSON.
1.2.1 Transfer of Customer Code
Customer code is made up of the ROM contents
and the list of the selected FASTROM options.
The ROM contents are to be sent on diskette, or
by electronic means, with the hexadecimal file
generated by the development tool. All unused
bytes must be set to FFh.
The selected options are communicated to SGSTHOMSON using the correctly filled OPTION
LIST appended.
1.2.2 Listing Generation and Verification
ROM Page
Device Address
Description
Page 0
0000h-007Fh
0080h-07FFh
Reserved
User ROM
Page 1
“STATIC”
0800h-0F9Fh
0FA0h-0FEFh
0FF0h-0FF7h
0FF8h-0FFBh
0FFCh-0FFDh
0FFEh-0FFFh
User ROM
Reserved
Interrupt Vectors
Reserved
NMI Vector
Reset Vector
Page 2
0000h-000Fh
0010h-07FFh
Reserved
User ROM
Page 3
0000h-000Fh
0010h-07FFh
Reserved
User ROM
When SGS-THOMSON receives the user’s ROM
contents, a computer listing is generated from it.
Table 2. ROM version Ordering Information
Sales Type
ST62P35BQ1/XXX
ST62P35BQ6/XXX
ST62P35BQ3/XXX (*)
(*) Advanced information
76/82
1
ROM
I/O
Temperature Range
Package
7948
36
0 to +70°C
-40 to 85°C
-40 to 125°C
PQFP52
ST62P35B
ST62P35B FASTROM MICROCONTROLLER OPTION LIST
Customer
Address
Contact
Phone No
Reference
SGS-THOMSON Microelectronics references
Device:
Package:
Temperature Range:
[ ] ST62P35B
[ ] Plastic Quad Flat (Tape & Reel)
[ ] 0°C to + 70°C[ ] - 40°C to + 85°C
Watchdog Selection:
[ ] Software Activation
[ ] Hardware Activation
Ports Pull-Up Selection: [ ] Yes
NMI Pull-Up Selection: [ ] Yes
Timer Pull-Up Selection: [ ] Yes
[ ] No
[ ] No
[ ] No
External STOP Mode Control:[ ] Enabled
[ ] Disabled
OSG:
[ ] Enabled
[ ] Disabled
Readout Protection:
[ ] Standard
[ ] Enabled
Comments :
Supply Operating Range in the application:
Oscillator Fequency in the application:
Notes
..................
Signature
Date
77/82
1
ST62P35B
Notes:
78/82
1
ST6235B
R
8-BIT ROM MCUs WITH A/D CONVERTER,
16-BIT AUTO-RELOAD TIMER, EEPROM, SPI AND UART
PRODUCT PREVIEW
■
■
■
■
■
■
■
■
■
■
■
■
■
■
■
■
■
■
■
■
■
3.0 to 6.0V Supply Operating Range
8 MHz Maximum Clock Frequency
-40 to +125°C Operating Temperature Range
Run, Wait and Stop Modes
5 Interrupt Vectors
Look-up Table capability in Program Memory
Data Storage in Program Memory:
User selectable size
Data RAM: 192 bytes
Data EEPROM: 128 bytes
36 I/O pins, fully programmable as:
– Input with pull-up resistor
– Input without pull-up resistor
– Input with interrupt generation
– Open-drain or push-pull output
– Analog Input
12 I/O lines can sink up to 20mA to drive LEDs
or TRIACs directly
8-bit Timer/ Counter with 7-bit programmable
prescaler
16-bit
Auto-reload
Timer
with
7-bit
programmable prescaler (AR Timer)
Digital Watchdog
8-bit A/D Converter with 24 analog inputs
8-bit Synchronous Peripheral Interface (SPI)
8-bit Asynchronous Peripheral Interface
(UART)
On-chip Clock oscillator can be driven by Quartz
Crystal or Ceramic resonator
Oscillator Safe Guard
One external Non-Maskable Interrupt
ST623x-EMU2 Emulation and Development
System (connects to an MS-DOS PC via a
parallel port).
PQFP52
(See end of Datasheet for Ordering Information)
DEVICE SUMMARY
DEVICE
ST6235B
ROM
(Bytes)
7948
I/O Pins
36
Rev. 2.3
March 1998
79/82
1
ST6235B
1 GENERAL DESCRIPTION
1.1 INTRODUCTION
1.2 ROM READOUT PROTECTION
The ST6235B is mask programmed ROM version
of ST62T35B OTP devices.
If the ROM READOUT PROTECTION option is
selected, a protection fuse can be blown to prevent any access to the program memory content.
They offer the same functionality as OTP devices,
selecting as ROM options the options defined in
the programmable option byte of the OTP version.
In case the user wants to blow this fuse, high voltage must be applied on the TEST pin.
Figure 1. Programming wave form
Figure 2. Programming Circuit
TES T
0.5s min
100 s ma x
5V
15
14V typ
10
47 m F
100nF
5
t
VS S
VDD
TEST
15 0 s typ
P ROTE CT
10 0mA
ma x
TE S T
14V
100nF
ZP D15
15V
4mA typ
t
VR02001
Note: ZPD15 is used for overvoltage protection
80/82
1
VR02003
ST6235B
ST6235B MICROCONTROLLER OPTION LIST
Customer
Address
Contact
Phone No
Reference
SGS-THOMSON Microelectronics references
Device:
[ ] ST6235B
Package:
[ ] Plastic Quad Flat (Tape & Reel)
Temperature Range:
[ ] 0°C to + 70°C[ ] - 40°C to + 85°C
Special Marking:
[ ] No
[ ] Yes ”_ _ _ _ _ _ _ _ _ _ _ ”
Authorized characters are letters, digits, ’.’, ’-’, ’/’ and spaces only.
Maximum character count:10
Watchdog Selection:
[ ] Software Activation
[ ] Hardware Activation
Ports Pull-Up Selection: [ ] Yes [ ] No
NMI Pull-Up Selection: [ ] Yes [ ] No
Timer Pull-Up Selection: [ ] Yes [ ] No
External STOP Mode Control:[ ] Enabled
[ ] Disabled
OSG:
[ ] Enabled
[ ] Disabled
ROM Readout Protection:[ ] Standard (Fuse cannot be blown)
[ ] Enabled (Fuse can be blown by the customer)
Note: No part is delivered with protected ROM.
The fuse must be blown for protection to be effective.
Comments :
Supply Operating Range in the application:
Oscillator Fequency in the application:
Notes
..................
Signature
Date
81/82
This is advance information from SGS-THOMSON .Details are subject to change without notice.
1
ST6235B
1.3 ORDERING INFORMATION
The following section deals with the procedure for
transfer of customer codes to SGS-THOMSON.
1.3.1 Transfer of Customer Code
Customer code is made up of the ROM contents
and the list of the selected mask options. The
ROM contents are to be sent on diskette, or by
electronic means, with the hexadecimal file generated by the development tool. All unused bytes
must be set to FFh.
The selected mask options are communicated to
SGS-THOMSON using the correctly filled OPTION LIST appended.
1.3.2 Listing Generation and Verification
When SGS-THOMSON receives the user’s ROM
contents, a computer listing is generated from it.
This listing refers exactly to the mask which will be
used to produce the specified MCU. The listing is
then returned to the customer who must thoroughly check, complete, sign and return it to
SGS-THOMSON. The signed listing forms a part
of the contractual agreement for the creation of the
specific customer mask.
The SGS-THOMSON Sales Organization will be
pleased to provide detailed information on contractual points.
Table 1. ROM Memory Map for ST6235B
ROM Page
Device Address
Description
Page 0
0000h-007Fh
0080h-07FFh
Reserved
User ROM
Page 1
“STATIC”
0800h-0F9Fh
0FA0h-0FEFh
0FF0h-0FF7h
0FF8h-0FFBh
0FFCh-0FFDh
0FFEh-0FFFh
User ROM
Reserved
Interrupt Vectors
Reserved
NMI Vector
Reset Vector
Page 2
0000h-000Fh
0010h-07FFh
Reserved
User ROM
Page 3
0000h-000Fh
0010h-07FFh
Reserved
User ROM
Table 2. ROM version Ordering Information
Sales Type
ST6235BQ1/XXX
ST6235BQ6/XXX
ST6235BQ3/XXX
ROM
I/O
Temperature Range
Package
7948
36
0 to +70°C
-40 to 85°C
-40 to 125°C
PQFP52
Information furnished is believed to be accurate and reliable. However, SGS-THOMSON Microelectronics assumes no responsibility for the
consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No
license is granted by implication or otherwise under any patent or patent rights of SGS-THOMSON Microelectronics. Specifications
mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information previously
supplied. SGS-THO MSON Microelectronics products are not authorized for use as critical components in life support devices or systems
without the express written approval of SGS-THO MSON Microelectronics.
1998 SGS-THOMSON Microelectronics - All rights reserved.
Printed in France by Imprimerie AGL
Purchase of I2C Components by SGS-THO MSON Microelectronics conveys a license under the Philips I2C Patent. Rights to use these
components in an I 2C system is granted provided that the system conforms to the I 2C Standard Specification as defined by Philips.
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