STMICROELECTRONICS ST62T28C

ST62T28C/E28C
8-BIT MCUs WITH A/D CONVERTER, AUTO-RELOAD
TIMER, UART, OSG, SAFE RESET AND 28-PIN PACKAGE
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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
User Programmable Options
20 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
8 I/O lines can sink up to 20mA to drive LEDs or
TRIACs directly
8-bit Timer/Counter with 7-bit programmable
prescaler
8-bit Auto-reload Timer with 7-bit programmable
prescaler (AR Timer)
Digital Watchdog
8-bit A/D Converter with 12 analog inputs
8-bit Asynchronous Peripheral Interface
(UART)
8-bit Synchronous Peripheral Interface (SPI)
On-chip Clock oscill ator can be driven by
Quartz Crystal, Ceramic resonator or RC
network
Oscillator Safe Guard
Low Voltage Detector for safe Reset
One external Non-Maskable Interrupt
ST623x-EMU2 Emulation and Development
System (connects to an MS-DOS PC via a
parallel port).
ST62T28C
ST62E28C
OTP
(Bytes)
7948
PS028
SS0P28
CDIP28W
DEVICE SUMMARY
DEVICE
PDIP28
EPROM
(Bytes)
7948
I/O Pins
(See end of Datasheet for Ordering Information)
20
20
Rev. 2.8
November 1999
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Table of Contents
Document
Page
ST62T28C/E28C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1 GENERAL DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.2 PIN DESCRIPTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.3 MEMORY MAP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.3.2 Program Space . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.3.3 Data Space . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
1.3.4 Stack Space . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
1.3.5 Data Window Register (DWR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
1.3.6 Data RAM Bank Register (DRBR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
1.4 PROGRAMMING MODES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
1.4.1 Option Bytes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2 CENTRAL PROCESSING UNIT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.2 CPU REGISTERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3 CLOCKS, RESET, INTERRUPTS AND POWER SAVING MODES . . . . . . . . . . . . . . . . . . . . .
3.1 CLOCK SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.1.1 Main Oscillator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.1.2 Low Frequency Auxiliary Oscillator (LFAO) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.1.3 Oscillator Safe Guard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.2 RESETS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.2.1 RESET Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.2.2 Power-on Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.2.3 Watchdog Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.2.4 LVD Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.2.5 Application Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.2.6 MCU Initialization Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.3 DIGITAL WATCHDOG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.3.1 Digital Watchdog Register (DWDR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.3.2 Application Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.4 IINTERRUPTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15
15
15
16
16
19
19
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20
20
20
21
23
25
25
27
3.4.1 Interrupt request . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.4.2 Interrupt Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.4.3 Interrupt Option Register (IOR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.4.4 Interrupt sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.5 POWER SAVING MODES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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28
29
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32
3.5.1 WAIT Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.5.2 STOP Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.5.3 Exit from WAIT and STOP Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4 ON-CHIP PERIPHERALS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.1 I/O PORTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.1.1 Operating Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .84
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32
32
33
34
34
35
4.1.2 Safe I/O State Switching Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
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4.1.3 ARTimer alternate functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.1.4 SPI alternate functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.1.5 UART alternate functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.1.6 I/O Port Option Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.1.7 I/O Port Data Direction Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.1.8 I/O Port Data Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.2 TIMER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.2.1 Timer Operating Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.2.2 Timer Interrupt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.2.3 Application Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.2.4 Timer Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3 AUTO-RELOAD TIMER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
38
38
38
40
40
40
41
42
42
43
43
44
4.3.1 AR Timer Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.2 Timer Operating Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.3 AR Timer Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.4 A/D CONVERTER (ADC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
44
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48
50
4.4.1 Application Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
4.5 U. A. R. T. (UNIVERSAL ASYNCHRONOUS RECEIVER/TRANSMITTER) . . . . . . . . . . . 52
4.5.1 Ports Interfacing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.5.2 Clock Generation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.5.3 Data Transmission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.5.4 Data Reception . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.5.5 Interrupt Capabilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.5.6 Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.6 SERIAL PERIPHERAL INTERFACE (SPI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
52
53
53
54
54
54
56
5 SOFTWARE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
5.1 ST6 ARCHITECTURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
5.2 ADDRESSING MODES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
5.3 INSTRUCTION SET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6 ELECTRICAL CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.1 ABSOLUTE MAXIMUM RATINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.2 RECOMMENDED OPERATING CONDITIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
59
64
64
65
6.3 DC ELECTRICAL CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
6.4 AC ELECTRICAL CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
6.5 A/D CONVERTER CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
6.6 TIMER CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
6.7 SPI CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
6.8 ARTIMER ELECTRICAL CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
7 GENERAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
7.1 PACKAGE MECHANICAL DATA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
7.2 ORDERING INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
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ST62P28C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
1 GENERAL DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
1.1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
1.2 ORDERING INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
1.2.1 Transfer of Customer Code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
1.2.2 Listing Generation and Verification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
ST6228C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
1 GENERAL DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
1.1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
1.2 ROM READOUT PROTECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
1.3 ORDERING INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
1.3.1 Transfer of Customer Code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
1.3.2 Listing Generation and Verification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
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ST62T28C/E28C
1 GENERAL DESCRIPTION
1.1 INTRODUCTION
The ST62T28C and ST62E28C devices are low
cost members of the ST62xx 8-bit HCMOS family
of microcontrollers, which are targeted at low to
medium complexity applications. All ST62xx devices are based on a building block approach: a
common core is surrounded by a number of onchip peripherals.
fined 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.
The ST62E28C is the erasable EPROM version of
the ST62T28C device, which may be used to emulate the ST62T28C device, as well as the respective ST6228C ROM devices.
These compact low-cost devices feature a Timer
comprising an 8-bit counter and a 7-bit programmable prescaler, an 8-bit Auto-Reload Timer, with
1 input capture channel, capability, a serial asynchronous port interface (UART), a synchronous
serial port interface, an 8-bit A/D Converter with 12
analog inputs and a Digital Watchdog timer, making them well suited for a wide range of automo-
OTP and EPROM devices are functionally identical. The ROM based versions offer the same functionality selecting as ROM options the options deFigure 1. Block Diagram
TEST/VPP
NMI
8-BIT
A/D CONVERTER
PORT A
PA0..PA1 / 20 mA Sink
PA2/ARTIMout / 20 mA Sink
PA3/ARTIMin/ 20 mA Sink
PA4..PA5/20 mA Sink
PORT B
PB4..PB6/Ain
PORT C
PC4..PC5/Ain
PC6..PC7/20 mA Sink
TEST
INTERRUPT
DATA ROM
USER
SELECTABLE
PROGRAM
Memory
7948 bytes
DATA RAM
192 Bytes
PORT D
UART
PD1/Ain/Scl
PD2/Ain/Sin
PD3/Ain/Sout
PD4/Ain/RXD1
PD5/Ain/TXD1
PD6,PD7/Ain
AUTORELOAD
TIMER
PC
STACK LEVEL 1
TIMER
STACK LEVEL 2
STACK LEVEL 3
STACK LEVEL 4
TIMER
8 BIT CORE
SPI
STACK LEVEL 5
STACK LEVEL 6
DIGITAL
WATCHD OG
POWER
SUPPLY
OSCILLATOR
RESET
VDD VSS
OSCin OSCout
RESET
(VPP on EPROM/OTP versions only)
VR01823F
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ST62T28C/E28C
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.
PC4 and PC5 can also be used as analog input for
the A/D converter, while PC6 and PC7 can sink
20mA for direct LED or TRIAC drive.
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.
PD1...PD7. These 7 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, input with interrupt generation and
pull-up resistor, analog input open-drain or pushpull output. In addition, 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 PD3/Scl can also be used respectively as data out, data in and clock pins for
the on-chip SPI.
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.
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 on-chip pullup at this pin.
Figure 2. ST62T28C/E28C Pin Configuration
PA0-PA5. These 6 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, input with interrupt generation and
pull-up resistor, open-drain or push-pull outputs.
PA2/ARTIMout and PA3/ARTIMin can be used respectively as output and input pins for the embedded 8-bit Auto-Reload Timer.
V DD
TIMER
OSCin
OSCout
NMI
In addition, PA0-PA5 can sink 20mA for direct LED
or TRIAC drive.
PB4...PB6. These 3 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, input with interrupt generation and
pull-up resistor, open-drain or push-pull outputs,
analog inputs for the A/D converter.
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, input with interrupt generation and
pull-up resistor, open-drain or push-pull output.
6/84
6
PC7*
PC6*
Ain/PC5
Ain/PC4
TEST/VPP(1)
RESET
Ain/PB6
Ain/PB5
Ain/PB4
(1) V
PP
1
2
3
4
5
6
7
8
9
10
11
12
13
14
28
27
26
25
24
23
22
21
20
19
18
17
16
15
VSS
PA0*
PA1*
PA2*/ARTIMout
PA3*/ARTIMin
PA4*
PA5*
PD1/Ain/Scl
PD2/Ain/Sin
PD3/Ain/Sout
PD4/Ain/RXD1
PD5/Ain/TXD1
PD6/Ain
PD7/Ain
on EPROM/OTP only
(*) 20 mA Sink
VR01804B
ST62T28C/E28C
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).
(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 0007FFh 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 4K pages. 4 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 common
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
7/84
7
ST62T28C/E28C
MEMORY MAP (Cont’d)
Table 1. ST62E28C/T28C 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 STMicroelectronics (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 interrupt occurs between the two instructions the PRPR is not affected.
8/84
8
Program ROM Page Register (PRPR)
Address: CAh
— Write Only
7
0
-
-
-
-
-
-
PRPR1 PRPR0
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 in Table 2.
This register is undefined on Reset. Neither read
nor single bit instructions may be used to address
this register.
Table 2. 6Kbytes 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 STMicroelectronics,
to gain access to the Program memory contents.
Returned parts with a protection set can therefore
not be accepted.
ST62T28C/E28C
MEMORY MAP (Cont’d)
1.3.3 Data Space
Table 4. ST62T28C/E28C Data Memory Space
DATA RAM BANKS
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
In ST6228C and ST62E28C 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 pages can also be addressed using banks of 64 bytes located between addresses
00h 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 Banks
Device
ST62T28C/E28C
RAM
2 x 64 bytes
DATA ROM WINDOW AREA
X REGISTER
Y REGISTER
V REGISTER
W REGISTER
DATA RAM
PORT A DATA REGISTER
PORT B DATA REGISTER
PORT C DATA REGISTE R
PORT D DATA REGISTE R
PORT A DIRECTION REGISTE R
PORT B DIRECTION REGISTE R
PORT C DIRECT ION REGISTE R
PORT D DIRECT ION REGISTE R
INTERRUPT OPTION REGISTER
DATA ROM WIND OW REGISTE R
ROM BANK SELECT REGISTE R
RAM BANK SELECT REGISTE R
PORT A OPTION REGISTER
PORT B OPTION REGISTER
PORT C OPTION REGISTER
PORT D OPTION REGISTER
A/D DATA REGISTER
A/D CONTROL REGISTER
TIMER 1 PRESCALE R REGISTER
TIMER 1 COUNTE R REGISTER
TIMER 1 STATUS/CONTROL REGISTER
RESERVED
UART DATA SHIFT REGISTER
UART STATUS CONTROL REGISTER
WATCHDOG REGISTER
RESERVED
I/O INTER RUPT POLARITY REGISTER
SPI INTERRUPT DISAB LE REGISTE R
SPI DATA SHIFT REGISTER
RESERVED
ARTIMER MODE/CONTROL REGISTER
ARTIME R STATUS/CONTROL REGISTER ARSC0
ARTIME R STATUS/CONTROL REGISTER ARSC1
RESERVED
ARTIMER RELOAD/CAPTURE REGIST ER
ARTIMER COMPARE REGISTER
. ARTIMER LOAD REGISTER
RESERVED
ACCUMULATOR
* WRIT E ONLY REGISTER
000h
03Fh
040h
07Fh
080h
081h
082h
083h
084h
0BFh
0C0h
0C1h
0C2h
0C3h
0C4h
0C5h
0C6h
0C7h
0C8h*
0C9h*
0CAh*
0CBh*
0CCh
0CDh
0CEh
0CFh
0D0h
0D1h
0D2h
0D3h
0D4h
0D5h
0D6h
0D7h
0D8h
0D9h
0DAh
0DCh*
0DDh
0DEh
0E4h
0E5h
0E6h
0E7h
0E8h
0E9h
0EAh
0EBh
0ECh
OFFh
9/84
9
ST62T28C/E28C
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 singlebit 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 00h
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 = DWR6-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
13
DATA ROM
WINDOW REGISTER 7
CONTENTS
12
11
10
9
8
7
6
6
5
4
3
2
1
0
(DWR)
0
5
4
3
2
1
0 PROGRAM SPACE ADDRESS
READ
5
4
3
2
1
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
0
0
0
1
0
1
1
0
0
1
0
0
0
1
1
0
0
1
DATA SPACE ADDRESS
59h
VR01573A
10/84
10
ST62T28C/E28C
MEMORY MAP (Cont’d)
1.3.6 Data RAM Bank Register (DRBR)
Address: CBh — Write only
7
-
0
-
-
DRBR4 DRBR3
-
-
-
Bit 7-5 = These bits are not used
Bit 4 - DRBR4. This bit, when set, selects RAM
Page 2.
Bit 3 - DRBR3. This bit, when set, selects RAM
Page 1.
Bit 2.0 These bits are not used.
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 location 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 bank of
the Data Space. The number of banks has to be
loaded in the DRBR register and the instruction
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.
Notes:
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.
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
ST62T28C/E28C
00h
None
01h
Reserved
02h
Reserved
08h
RAM Page 1
10h
RAM Page 2
other
Reserved
11/84
11
ST62T28C/E28C
1.4 PROGRAMMING MODES
1.4.1 Option Bytes
The two Option Bytes allow 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 bytes are located in a non-user map.
No address has to be specified.
EPROM Code Option Byte (LSB)
7
0
PROPORT
OSCIL
TECT
PULL
-
NMI
PULL
TIM
WDACT
PULL
OSGEN
EPROM Code Option Byte (MSB)
15
-
8
-
-
ADC
UART
SYNCHRO FRAME
-
EXTCNTL
LVD
D15-D13. Reserved. Must be cleared.
ADC SYNCHRO. When set, an A/D conversion is
started upon WAIT instruction execution, in order
to reduce supply noise. When this bit is low, an A/
D conversion is started as soon as the STA bit of
the A/D Converter Control Register is set.
D11. UART Frame. When set, UART transmission
and reception are based on a 11-bit frame. When
cleared, a 10-bit frame is used.
D10. Reserved.
EXTCNTL. External STOP MODE control.. When
EXTCNTL is high, STOP mode is available with
12/84
12
watchdog active by setting NMI pin to one. When
EXTCNTL is low, STOP mode is not available with
the watchdog active.
LVD. LVD RESET enable.When this bit is set, safe
RESET is performed by MCU when the supply
voltage is too low. When this bit is cleared, only
power-on reset or external RESET are active.
PROTECT. Readout Protection. 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.. When
this bit is low, the user program can be read.
OSCIL. Oscillator selection. When this bit is low,
the oscillator must be controlled by a quartz crystal, a ceramic resonator or an external frequency.
When it is high, the oscillator must be controlled by
an RC network, with only the resistor having to be
externally provided.
D5. Port Pull. This bit must be set high to disable
pull-up at reset on the I/O port. When this bit is
low,I/O ports are in input with pull-up.
D4. Reserved. Must be cleared to zero.
NMI PULL. NMI Pull-Up. 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.
TIM PULL.TIM Pull-Up. 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.
WDACT. This bit controls the watchdog activation.
When it is high, hardware activation is selected.
The software activation is selected when WDACT
is low.
OSGEN. Oscillator Safe Guard. 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).
ST62T28C/E28C
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.
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.
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.
Figure 6. ST6 Core Block Diagram
0,01 TO 8MHz
RESET
OSCin
OSCout
INTERRUPTS
CONTROLLER
DATA SPACE
OPCODE
FLAG
VALUES
CONTROL
SIGNALS
DATA
ADDRESS /READ LINE
2
RAM/EEPR OM
PROGRAM
ADDRESS 256
DECODER
ROM/EPRO M
A-DATA
B-DATA
DATA
ROM/EPROM
DEDICAT IONS
ACCUMULATOR
12
Program Counter
and
6 LAYER STACK
FLAGS
ALU
RESULTS TO DATA SPACE (WRITE LINE)
VR01811
13/84
13
ST62T28C/E28C
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
- Reset
PC= 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
14/84
14
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.
lFigure 7. ST6 CPU Programming Mode
INDEX
REGISTER
b11
b7
X REG. POINTER
b0
b7
Y REG. POINTER
b0
b7
V REGISTER
b7
W REGISTER
b0
b7
ACCUM ULATO R
b0
PROGRAM COUNTER
SHORT
DIRECT
ADDRESSING
MODE
b0
b0
SIX LEVELS
STACK REGISTER
NORMAL FLAGS
C
Z
INTERRUPT FLAGS
C
Z
NMI FLAGS
C
Z
VA000423
ST62T28C/E28C
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, or with an external resistor
(RNET). 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 (f INT) as a
function of VDD, in order to guarantee correct operation. These functions are illustrated in Figure 2,
Figure 3, Figure 4 and Figure 5.
Figure 1 illustrates various possible oscillator configurations using an external crystal or ceramic resonator, an external clock input, an external resistor
(RNET), or the lowest cost solution using only the
LFAO. CL1 an CL2 should have a capacitance in the
range 12 tST6_CLK1o 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, the A/D converter and the
Watchdog timer, and by 13 to drive the CPU core,
as may be seen in Figure 4.
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 oscillator configuration may be specified by selecting theappropriate option.When the CRYSTAL/
RESONATORoption isselected, itmustbeusedwith
a quartz crystal, a ceramic resonator or an external
signal providedonthe OSCinpin.When theRC NETWORK option is selected, the system clock is generated by an external resistor.
The main oscillator can be turned off (when the
OSG ENABLED option is selected) by setting the
OSCOFF bit of the ADC Control Register. The
Low Frequency Auxiliary Oscillator is automatically started.
Figure 8. Oscillator Configurations
CRYSTAL/RES ONATOR CLOCK
CRYSTAL/RESON ATOR option
ST6xxx
OSCin
OSCout
CL1n
C L2
EXTERNAL CLOCK
CRYSTAL/RESON ATOR option
ST6xxx
OSCin
OSCout
NC
RC NETW ORK
RC NETW ORK option
ST6xxx
OSCin
OSCout
NC
RNET
INTEGRA TED CLOCK
CRYSTAL/RESON ATOR option
OSG ENABLED option
ST6xxx
OSCin
OSCout
NC
15/84
15
ST62T28C/E28C
CLOCK SYSTEM (Cont’d)
Turning on the main oscillator is achieved by resetting the OSCOFF bit of the A/D Converter Control 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.
ADCR
Address: 0D1h — Read/Write
7
ADCR ADCR ADCR ADCR ADCR
7
6
5
4
3
0
OSC
OFF
ADCR ADCR
1
0
Bit 7-3, 1-0= ADCR7-ADCR3, ADCR1-ADCR0:
ADC Control Register . These bits are not used.
Bit 2 = OSCOFF. 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 func-
16/84
16
tions: 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 in Figure
2). 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 in Figure 5.
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 3).
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.
Warning: Care has to be taken when using the
OSG, as the internal frequency is defined between
a minimum and a maximum value and is not accurate.
For precise timing measurements, it is not recommended to use the OSG and it should not be enabled in applications that use the SPI or the UART.
It should also be noted that power consumption in
Stop mode is higher when the OSG is enabled
(around 50µA at nominal conditions and room
temperature).
ST62T28C/E28C
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
17/84
17
ST62T28C/E28C
CLOCK SYSTEM (Cont’d)
Figure 11. Clock Circuit Block Diagram
POR
Core
: 13
OSG
TIMER 1
M
U
X
MAIN
OSCILLATOR
fINT
Watchdog
: 12
LFAO
:1
Main Oscillator off
Figure 12. Maximum Operating Frequency (fMAX) versus Supply Voltage (VDD)
Maximum FREQU ENCY (MHz)
8
4
FUNCTIONALITY IS NOT
GUARANTEED
IN THIS AREA
7
6
5
4
3
3
fOSG
fOSG Min (at 85°C)
2
fOSG Min (at 125°C)
2
1
1
2.5
3
3.6
4
4.5
5
5.5
6
SUPPLY VOLTAGE (VDD )
VR01807J
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
18/84
18
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 fOSG.
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 fOSG.
ST62T28C/E28C
3.2 RESETS
The MCU can be reset in four ways:
– by the external Reset input being pulled low;
– by Power-on Reset;
– by the digital Watchdog peripheral timing out.
– by Low Voltage Detection (LVD)
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.
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 by detecting around 2V a dynamic
(rising edge) variation of the VDD Supply. 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.
To ensure correct start-up, the user should take
care that the VDD Supply is stabilized at a sufficient level for the chosen frequency (see recommended operation) before the reset signal is released. In addition, supply rising must start from
0V.
As a consequence, the POR does not allow to supervise static, slowly rising, or falling, or noisy
(presenting oscillation) VDD supplies.
An external RC network connected to the RESET
pin, or the LVD reset can be used instead to get
the best performances.
Figure 13. Reset and Interrupt Processing
RESET
NMI MASK SET
INT LATCH CLEARED
( IF PRESENT )
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
19/84
19
ST62T28C/E28C
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 LVD Reset
The on-chip Low Voltage Detector, selectable as
user option, features static Reset when supply
voltage is below a reference value. Thanks to this
feature, external reset circuit can be removed
while keeping the application safety. This SAFE
RESET is effective as well in Power-on phase as
in power supply drop with different reference val-
ues, allowing hysteresis effect. Reference value in
case of voltage drop has been set lower than the
reference value for power-on in order to avoid any
parasitic Reset when MCU start’s running and
sinking current on the supply.
As long as the supply voltage is below the reference value, there is a internal and static RESET
command. The MCU can start only when the supply voltage rises over the reference value. Therefore, only two operating mode exist for the MCU:
RESET active below the voltage reference, and
running mode over the voltage reference as
shown on the Figure 14, that represents a powerup, power-down sequence.
Note: When the RESET state is controlled by one
of the internal RESET sources (Low Voltage Detector, Watchdog, Power on Reset), the RESET
pin is tied to low logic level.
Figure 14. LVD Reset on Power-on and Power-down (Brown-out)
VDD
VUp
Vdn
RESET
RESET
time
VR02106A
3.2.5 Application Notes
No external resistor is required between VDD and
the Reset pin, thanks to the built-in pull-up device.
20/84
20
Direct external connection of the pin RESET to
VDD must be avoided in order to ensure safe behaviour of the internal reset sources (AND.Wired
structure).
ST62T28C/E28C
RESETS (Cont’d)
3.2.6 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 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 15. Reset and Interrupt Processing
RESET
JP
JP:2 BYTES/4 CYCLES
RESET
VECTOR
INITIALIZATION
ROUTINE
RETI: 1 BYTE/2 CYCLES
RETI
VA00181
Figure 16. Reset Block Diagram
VDD
fOSC
COUNTER
RPU
RESD1)
RESET
ST6
INTERNA L
RESET
CK
AND. Wired
RESET
RESET
POWER ON RESET
WATCHD OG RESET
LVD RESET
VR02107A
1) Resistive ESD protection. Value not guaranteed.
21/84
21
ST62T28C/E28C
RESETS (Cont’d)
Table 6. Register Reset Status
Register
Address(es)
Port Data Registers
Port Direction Register
Port Option Register
Interrupt Option Register
TIMER Status/Control
0C0h to 0C3h
0C4h to 0C7h
0CCh to 0CFh
0C8h
0D4h
AR TIMER Mode/Control Register
AR TIMER Status/Control Register 0
AR TIMER Status/Control Register 1
0E5h
0E6h
0E7h
X, Y, V, W, Register
Accumulator
Data RAM
Data RAM Page Register
Data ROM Window Register
A/D Result Register
ARTIMER Reload/Capture Register
ARTIMER Compare Registers
ARTIMER Load Registers
080H TO 083H
0FFh
084h to 0BFh
0CBh
0C9h
0D0h
0E9h
0EAh
0EBh
TIMER Counter Register
TIMER Prescaler Register
Watchdog Counter Register
A/D Control Register
0D3h
0D2h
0D8h
0D1h
UART Status Control
0D7h
22/84
22
Status
Comment
I/O are Input with or without pull-up
depending on PORT PULL option
00h
Interrupt disabled
TIMER disabled
AR TIMER disabled
Undefined
FFh
7Fh
FEh
40h
Max count loaded
A/D in Stand-by
UART disabled
ST62T28C/E28C
3.3 DIGITAL WATCHDOG
The digital Watchdog consists of a reloadable
downcounter timer which can be used to provide
controlled recovery from software upsets.
The Watchdog circuit generates a Reset when the
downcounter reaches zero. User software can
prevent this reset by reloading the counter, and
should therefore be written so that the counter is
regularly reloaded while the user program runs
correctly. In the event of a software mishap (usually caused by externally generated interference),
the user program will no longer behave in its usual
fashion and the timer register will thus not be reloaded periodically. Consequently the timer will
decrement down to 00h and reset the MCU. In order to maximise the effectiveness of the Watchdog
function, user software must be written with this
concept in mind.
Watchdog behaviour is governed by two options,
known as “WATCHDOG ACTIVATION” (i.e.
HARDWARE or SOFTWARE) and “EXTERNAL
STOP MODE CONTROL” (see Table 7).
In the SOFTWARE option, the Watchdog is disabled until bit C of the DWDR register has been set.
When the Watchdog is disabled, low power Stop
mode is available. Once activated, the Watchdog
cannot be disabled, except by resetting the MCU.
In the HARDWARE option, the Watchdog is permanently enabled. Since the oscillator will run continuously, low power mode is not available. The
STOP instruction is interpreted as a WAIT instruction, and the Watchdog continues to countdown.
However, when the EXTERNAL STOP MODE
CONTROL option has been selected low power
consumption may be achieved in Stop Mode.
Execution of the STOP instruction is then governed by a secondary function associated with the
NMI pin. If a STOP instruction is encountered
when the NMI pin is low, it is interpreted as WAIT,
as described above. If, however, the STOP instruction is encountered when the NMI pin is high,
the Watchdog counter is frozen and the CPU enters STOP mode.
When the MCU exits STOP mode (i.e. when an interrupt is generated), the Watchdog resumes its
activity.
Table 7. Recommended Option Choices
Functions Required
Stop Mode & Watchdog
Stop Mode
Watchdog
Recommended Options
“EXTERNAL STOP MODE” & “HARDWARE WATCHDOG”
“SOFTWARE WATCHDOG”
“HARDWARE WATCHDOG”
23/84
23
ST62T28C/E28C
24/84
24
Figure 17. Watchdog Counter Control
D0
C
D1
SR
D2
D3
D4
D5
WATCHDOG COUNTER
WATCHDOG CONTROL REGISTER
DIGITAL WATCHDOG (Cont’d)
The Watchdog is associated with a Data space
register (Digital WatchDog Register, DWDR, location 0D8h) which is described in greater detail in
Section 3.3.1 Digital Watchdog Register (DWDR).
This register is set to 0FEh on Reset: bit C is
cleared to “0”, which disables the Watchdog; the
timer downcounter bits, T0 to T5, and the SR bit
are all set to “1”, thus selecting the longest Watchdog timer period. This time period can be set to the
user’s requirements by setting the appropriate value for bits T0 to T5 in the DWDR register. The SR
bit must be set to “1”, since it is this bit which generates the Reset signal when it changes to “0”;
clearing this bit would generate an immediate Reset.
It should be noted that the order of the bits in the
DWDR register is inverted with respect to the associated bits in the down counter: bit 7 of the
DWDR register corresponds, in fact, to T0 and bit
2 to T5. The user should bear in mind the fact that
these bits are inverted and shifted with respect to
the physical counter bits when writing to this register. The relationship between the DWDR register
bits and the physical implementation of the Watchdog timer downcounter is illustrated in Figure 17.
Only the 6 most significant bits may be used to define the time period, since it is bit 6 which triggers
the Reset when it changes to “0”. This offers the
user a choice of 64 timed periods ranging from
3,072 to 196,608 clock cycles (with an oscillator
frequency of 8MHz, this is equivalent to timer periods ranging from 384µs to 24.576ms).
RESET
T5
T4
T3
T2
D6
T1
D7
T0
÷28
OSC ÷12
VR02068A
ST62T28C/E28C
DIGITAL WATCHDOG (Cont’d)
3.3.1 Digital Watchdog Register (DWDR)
Address: 0D8h — Read/Write
Reset status: 1111 1110b
7
T0
0
T1
T2
T3
T4
T5
SR
C
Bit 0 = C: Watchdog Control bit
If the hardware option is selected, this bit is forced
high and the user cannot change it (the Watchdog
is always active). When the software option is selected, the Watchdog function is activated by setting bit C to 1, and cannot then be disabled (save
by resetting the MCU).
When C is kept low the counter can be used as a
7-bit timer.
This bit is cleared to “0” on Reset.
Bit 1 = SR: Software Reset bit
This bit triggers a Reset when cleared.
When C = “0” (Watchdog disabled) it is the MSB of
the 7-bit timer.
This bit is set to “1” on Reset.
Bits 2-7 = T5-T0: Downcounter bits
It should be noted that the register bits are reversed and shifted with respect to the physical
counter: bit-7 (T0) is the LSB of the Watchdog
downcounter and bit-2 (T5) is the MSB.
These bits are set to “1” on Reset.
3.3.2 Application Notes
The Watchdog plays an important supporting role
in the high noise immunity of ST62xx devices, and
should be used wherever possible. Watchdog related options should be selected on the basis of a
trade-off between application security and STOP
mode availability.
When STOP mode is not required, hardware activation without EXTERNAL STOP MODE CONTROL should be preferred, as it provides maximum security, especially during power-on.
When STOP mode is required, hardware activation and EXTERNAL STOP MODE CONTROL
should be chosen. NMI should be high by default,
to allow STOP mode to be entered when the MCU
is idle.
The NMI pin can be connected to an I/O line (see
Figure 18) to allow its state to be controlled by software. The I/O line can then be used to keep NMI
low while Watchdog protection is required, or to
avoid noise or key bounce. When no more
processing is required, the I/O line is released and
the device placed in STOP mode for lowest power
consumption.
When software activation is selected and the
Watchdog is not activated, the downcounter may
be used as a simple 7-bit timer (remember that the
bits are in reverse order).
The software activation option should be chosen
only when the Watchdog counter is to be used as
a timer. To ensure the Watchdog has not been unexpectedly activated, the following instructions
should be executed within the first 27 instructions:
jrr 0, WD, #+3
ldi WD, 0FDH
25/84
25
ST62T28C/E28C
DIGITAL WATCHDOG (Cont’d)
These instructions test the C bit and Reset the
MCU (i.e. disable the Watchdog) if the bit is set
(i.e. if the Watchdog is active), thus disabling the
Watchdog.
In all modes, a minimum of 28 instructions are executed after activation, before the Watchdog can
generate a Reset. Consequently, user software
should load the watchdog counter within the first
27 instructions following Watchdog activation
(software mode), or within the first 27 instructions
executed following a Reset (hardware activation).
It should be noted that when the GEN bit is low (interrupts disabled), the NMI interrupt is active but
cannot cause a wake up from STOP/WAIT modes.
Figure 18. A typical circuit making use of the
EXERNAL STOP MODE CONTROL feature
SWITCH
NMI
I/O
VR02002
Figure 19. Digital Watchdog Block Diagram
RESET
Q
RSFF
R
S
-27
DB 1.7 LOAD SET
DB0
-2 8
SET
-12
OSCILLATOR
CLOCK
8
WRITE
RESET
DATA BUS
VA00010
26/84
26
ST62T28C/E28C
3.4 IINTERRUPTS
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)
ically reset by the core at the beginning of the nonmaskable 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
CLEARED
SET
3.4.1 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 automat-
ESB
CLEARED
SET
LES
CLEARED
OTHERS
Enable all interrupts
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
NOT USED
27/84
27
ST62T28C/E28C
INTERRUPTS (Cont’d)
3.4.2 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.
– Theassociated interrupt vectoris loaded inthe PC.
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)
28/84
28
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 20. Interrupt Processing Flow Chart
INS TRU CTION
FETCH
INS TRU CTION
EXEC UTE
IN STRUC TION
WAS
THE INS TRU CTION
A RE TI ?
LOAD PC FROM
INT ERR UP T VEC TOR
NO
(FFC/FFD)
YES
YES
IS THE CORE
ALREADY IN
NORMAL MODE?
?
SET
INTER RU PT MASK
NO
C LEAR
INT ERR UP T MASK
SELECT
PROGRAM FLAGS
PUSH THE
PC IN TO THE STACK
SELECT
IN TER NA L MODE FLAG
”POP”
THE STACK ED PC
C HEC K IF THER E IS
AN IN TER RUP T R EQUEST
AN D INTE RRU PT MASK
NO
?
YES
VA000014
ST62T28C/E28C
INTERRUPTS (Cont’d)
3.4.3 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.
3.4.4 Interrupt sources
Interrupt sources available on the ST62E28C/
T28C are summarized in the Table 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
ARTIMER
ARMC
E5h
SPI
Port PAn
Port PBn
SIDR
ORPA-DRPA
ORPB-DRPB
Port PCn
Port PDn
ORPC-DRPC
ORPD-DRPD
Peripheral
Register
Mask bit
Masked Interrupt Source
All Interrupts, excluding NMI
DCh
C0h-C4h
C1h-C5h
GEN
ETI
EAI
RXIEN
TXIEN
OVIE
CPIE
EIE
ALL
ORPAn-DRPAn
ORPBn-DRPBn
TMZ: TIMER Overflow
EOC: End of Conversion
RXRDY: Byte received
TXMT: Byte sent
OVF: ARTIMER Overflow
CPF: Successful compare
EF: Active edge on ARTIMin
End of Transmission
PAn pin
PBn pin
C2h-C6h
C3h-C7h
ORPCn-DRPCn
ORPDn-DRPDn
PCn pin
PDn pin
Interrupt
source
All
source 4
source 4
source 4
source 3
source 1
source 1
source 2
source 0
source 2
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ST62T28C/E28C
INTERRUPTS (Cont’d)
Interrupt Polarity Register (IPR)
generates interrupt on rising edge. At reset, IPR is
cleared and all port interrupts are not inverted (e.g.
Port C generates interrupts on falling edges).
Address: DAh — Read/Write
7
0
-
-
-
-
Bit 7 - Bit 4 = Unused.
PortD PortC PortA PortB
Bit 3 = Port D Interrupt Polarity.
Bit 2 = Port C Interrupt Polarity.
In conjunction with I/O 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 = A; port C
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 occurrence
Port D occurrence
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
IPR1
IOR6
Port A occurrence
Interrupt
source
1
1
1
1
0
0
0
1
1
X
0
1
0
1
X
falling edge
low level
rising edge
high level
Disabled
1
IPR2
0
1
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Port C occurrence
falling edge
rising edge
Interrupt source
0
ST62T28C/E28C
INTERRUPTS (Cont’d)
Figure 21. Interrupt Block Diagram
FROM REGISTER PORT A,B,C,D
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 1
PORT A
Bits
FF
CLK
Q
CLR
PBE
0
MUX
INT #1 (FF6,7)
I1 Start
1
IOR bit 6 (LES)
SPI
RESTART
FROM
STOP/WAIT
IPR Bit 0
FF
CLK
Q
CLR
PBE
PORT B
Bits
IOR bit 5 (ESB)
INT #2 (FF4,5)
I2 Start
IPR Bit 3
PBE
PORT D
Bits
OVF
OVIE
ARTIMER
INT #3 (FF2,3)
CPF
CPIE
EF
EIE
TMZ
ETI
TIMER 1
EAI
EOC
INT #4 (FF0,1)
RXRDY
RXIEN
UART
TXMT
TXIEN
IOR bit 4(GEN)
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ST62T28C/E28C
3.5 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.
3.5.1 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.
3.5.2 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.
ST62T28C/E28C
POWER SAVING MODE (Cont’d)
3.5.3 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.
3.5.3.1 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.
3.5.3.2 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.
3.5.3.3 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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ST62T28C/E28C
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 pull-ups
and no interrupt generation is selected for all the
pins, thus avoiding pin conflicts.
Figure 22. I/O Port Block Diagram
SIN CONTROLS
RESET
VDD
DATA
DIRECTION
REGISTE R
VDD
INPUT /OUTPUT
DATA
REGISTE R
SHIFT
REGIST ER
OPTION
REGISTE R
SOUT
TO INTERRU PT
TO ADC
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VA00413
ST62T28C/E28C
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
Optio n
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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ST62T28C/E28C
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
23. 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
Warning: Care must also be taken to not use instructions that act on a whole port register (INC,
DEC, or read operations) when all 8 bits are not
available on the device. Unavailable bits must be
masked by software (AND instruction).
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 23. 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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ST62T28C/E28C
I/O PORTS (Cont’d)
Table 13. I/O Port configuration for the ST62T28C/E28C
MODE
Input
(Reset state if PORT
PULL option disabled)
AVAILABLE ON(1)
SCHEMATIC
PA0-PA5
PB4-PB6
PC4-PC7
PD1-PD7
Data in
Interrupt
Input
with pull up
(Reset state if PORT
PULL option enabled)
PA0-PA5
PB4-PB6
PC4-PC7
PD1-PD7
Data in
Interrupt
Input
with pull up
with interrupt
PA0-PA5
PB4-PB6
PC4-PC7
PD1-PD7
Data in
Interrupt
Analog Input
Open drain output
5mA
PA4-PA5
PB4-PB6
PC4-PC7
PD1-PD7
ADC
PB4-PB6
PC4-PC7
PD1-PD7
Data out
Open drain output
20mA
PA0-PA5
Push-pull output
5mA
PB4-PB6
PC4-PC7
PD1-PD7
Data out
Push-pull output
20mA
PA0-PA5
VR01992A
Note 1. Provided the correct configuration has been selected.
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ST62T28C/E28C
I/O PORTS (Cont’d)
4.1.3 ARTimer alternate functions
When bit PWMOE of register ARMC is low, pin ARTIMout/PA2 is configured as any standard pin of
port B through the port registers. When PWMOE is
high, ARTIMout/PA2 is the PWM output, independently of the port registers configuration. ARTIMin/
PA3 is connected through the port registers as any
standard pin of port B. To use PARTIMin/PA3 as
AR Timer input, it must be configured as input
though DDRB.
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
used as data in and data clock (Slave mode) for
the SPI. All input modes are available and I/O’s
can be read independently of the SPI at any time.
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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 independently 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.
ST62T28C/E28C
I/O PORTS (Cont’d)
Figure 24. Peripheral Interface Configuration of SPI, UART and AR Timer
VDD
PID
RXD
PD4/RXD1
DR
UART
IARTOE
PID
MUX
PD5/TXD1
DR
0
1
TXD
PID PP/OD
OPR
PD3/Sout
MUX
1
0
DR
OUT
PID
IN
DR
PD2/Sin
SYNCHRONOUS
SERIAL I/O
PID
CLOCK
DR
PD1/Scl
PID
ARTIMin
PA3/ARTIMin
DR
ARTIMER
PID
OR
PWMOE
PA2/ARTIMout
1
MUX
0
ARTI Mout
DR
VR01661D
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ST62T28C/E28C
I/O PORTS (Cont’d)
4.1.6 I/O Port Option Registers
ORA/B/C/D (CCh PA, CDh PB, CEh PC, CFh PD)
Read/Write
7
Px7
Px6
Px5
Px4
Px3
Px2
Px1
0
7
Px0
Px7
Bit 7-0 = Px7 - Px0: Port A, B, C, and D Option
Register bits.
4.1.7 I/O Port Data Direction Registers
DDRA/B/C/D (C4h PA, C5h PB, C6h PC, C7h PD)
Read/Write
7
Px7
0
Px6
Px5
Px4
Px3
Px2
Px1
Px0
Bit 7-0 = Px7 - Px0: Port A, B, C, and D Data Direction Registers bits.
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4.1.8 I/O Port Data Registers
DRA/B/C/D (C0h PA, C1h PB, C2h PC, C3h PD)
Read/Write
0
Px6
Px5
Px4
Px3
Px2
Px1
Px0
Bit 7-0 = Px7 - Px0: Port A, B, C, and D Data Registers bits.
ST62T28C/E28C
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 25. Timer Block Diagram
DATABUS 8
8
8
PSC
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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ST62T28C/E28C
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 (f INT ÷ 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 26. Timer Working Principle
7-BIT PRESCALER
BIT0
CLOCK
0
BIT1
1
BIT2
2
BIT3
BIT4
3
4
8-1 MULTIPLEXER
BIT6
BIT5
6
5
7
PS0
PS1
PS2
BIT0
BIT1
BIT2
BIT3
BIT4
BIT5
BIT6
BIT7
8-BIT COUNTER
VA00186
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ST62T28C/E28C
TIMER (Cont’d)
4.2.3 Application Notes
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
Timer Status Control Register (TSCR)
Address: 0D4h — Read/Write
7
TMZ
0
ETI
TOUT DOUT
PSI
PS2
PS1
PS0
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 6 = ETI: Enable Timer Interrupt
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.
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 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
PS1
0
0
1
PS0
0
1
0
Divided by
1
2
4
0
1
1
1
1
1
0
0
1
1
1
0
1
0
1
8
16
32
64
128
Timer Counter Register TCR
Address: 0D3h — Read/Write
7
D7
0
D6
D5
D4
D3
D2
D1
D0
Bit 7-0 = D7-D0: Counter Bits.
Prescaler Register PSC
Address: 0D2h — Read/Write
7
D7
0
D6
D5
D4
D3
D2
D1
D0
Bit 7 = D7: Always read as “0”.
Bit 6-0 = D6-D0: Prescaler Bits.
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ST62T28C/E28C
4.3 AUTO-RELOAD TIMER
The Auto-Reload Timer (AR Timer) on-chip peripheral consists of an 8-bit timer/counter with
compare and capture/reload capabilities and of a
7-bit prescaler with a clock multiplexer, enabling
the clock input to be selected as f INT, fINT/3 or an
external clock source. A Mode Control Register,
ARMC, two Status Control Registers, ARSC0 and
ARSC1, an output pin, ARTIMout, and an input
pin, ARTIMin, allow the Auto-Reload Timer to be
used in 4 modes:
– Auto-reload (PWM generation),
– Output compare and reload on external event
(PLL),
– Input capture and output compare for time measurement.
– Input capture and output compare for period
measurement.
The AR Timer can be used to wake the MCU from
WAIT mode either with an internal or with an external clock. It also can be used to wake the MCU
from STOP mode, if used with an external clock
signal connected to the ARTIMin pin. A Load register allows the program to read and write the
counter on the fly.
4.3.1 AR Timer Description
The AR COUNTER is an 8-bit up-counter incremented on the input clock’s rising edge. The counter is loaded from the ReLoad/Capture Register,
ARRC, for auto-reload or capture operations, as
well as for initialization. Direct access to the AR
counter is not possible; however, by reading or
writing the ARLR load register, it is possible to
read or write the counter’s contents on the fly.
The AR Timer’s input clock can be either the internal clock (from the Oscillator Divider), the internal
clock divided by 3, or the clock signal connected to
the ARTIMin pin. Selection between these clock
sources is effected by suitably programming bits
CC0-CC1 of the ARSC1 register. The output of the
AR Multiplexer feeds the 7-bit programmable AR
Prescaler, ARPSC, which selects one of the 8
available taps of the prescaler, as defined by
PSC0-PSC2 in the AR Mode Control Register.
Thus the division factor of the prescaler can be set
to 2n (where n = 0, 1,..7).
The clock input to the AR counter is enabled by the
TEN (Timer Enable) bit in the ARMC register.
When TEN is reset, the AR counter is stopped and
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the prescaler and counter contents are frozen.
When TEN is set, the AR counter runs at the rate
of the selected clock source. The counter is
cleared on system reset.
The AR counter may also be initialized by writing
to the ARLR load register, which also causes an
immediate copy of the value to be placed in the AR
counter, regardless of whether the counter is running or not. Initialization of the counter, by either
method, will also clear the ARPSC register, whereupon counting will start from a known value.
4.3.2 Timer Operating Modes
Four different operating modes are available for
the AR Timer:
Auto-reload Mode with PWM Generation. This
mode allows a Pulse Width Modulated signal to be
generated on the ARTIMout pin with minimum
Core processing overhead.
The free running 8-bit counter is fed by the prescaler’s output, and is incremented on every rising
edge of the clock signal.
When a counter overflow occurs, the counter is
automatically reloaded with the contents of the Reload/Capture Register, ARCC, and ARTIMout is
set. When the counter reaches the value contained in the compare register (ARCP), ARTIMout
is reset.
On overflow, the OVF flag of the ARSC0 register is
set and an overflow interrupt request is generated
if the overflow interrupt enable bit, OVIE, in the
Mode Control Register (ARMC), is set. The OVF
flag must be reset by the user software.
When the counter reaches the compare value, the
CPF flag of the ARSC0 register is set and a compare interrupt request is generated, if the Compare
Interrupt enable bit, CPIE, in the Mode Control
Register (ARMC), is set. The interrupt service routine may then adjust the PWM period by loading a
new value into ARCP. The CPF flag must be reset
by user software.
The PWM signal is generated on the ARTIMout
pin (refer to the Block Diagram). The frequency of
this signal is controlled by the prescaler setting
and by the auto-reload value present in the Reload/Capture register, ARRC. The duty cycle of
the PWM signal is controlled by the Compare Register, ARCP.
ST62T28C/E28C
AUTO-RELOAD TIMER (Cont’d)
Figure 27. AR Timer Block Diagram
DATA BUS
DDRA2
8
DRA2
AR COMPARE
REGISTER
8
PA2/
ARTIMout
CPF
R
COMPARE
S
8
f INT
M
f INT /3
U
PWMOE
OVF
8-Bit
7-Bit
AR PRESCALER
X
CC0-CC1
AR COUNTER
OVF
OVIE
LOAD
PS0-PS2
TCLD
EIE
EF
8
CPF
AR TIMER
INTERRUPT
CPIE
8
8
AR
AR
PA3/
ARTIMin
SL0-SL1
EF
SYNCHRO
RELOAD/CAPTURE
LOAD
REGISTER
REGISTER
8
8
DATA BUS
VR01660B
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ST62T28C/E28C
AUTO-RELOAD TIMER (Cont’d)
It should be noted that the reload values will also
affect the value and the resolution of the duty cycle
of PWM output signal. To obtain a signal on ARTIMout, the contents of the ARCP register must be
greater than the contents of the ARRC register.
The maximum available resolution for the ARTIMout duty cycle is:
Resolution = 1/[255-(ARRC)]
Where ARRC is the content of the Reload/Capture
register. The compare value loaded in the Compare Register, ARCP, must be in the range from
(ARRC) to 255.
The ARTC counter is initialized by writing to the
ARRC register and by then setting the TCLD (Timer Load) and the TEN (Timer Clock Enable) bits in
the Mode Control register, ARMC.
Enabling and selection of the clock source is controlled by the CC0, CC1, SL0 and SL1 bits in the
Status Control Register, ARSC1. The prescaler division ratio is selected by the PS0, PS1 and PS2
bits in the ARSC1 register.
In Auto-reload Mode, any of the three available
clock sources can be selected: Internal Clock, Internal Clock divided by 3 or the clock signal
present on the ARTIMin pin.
Figure 28. Auto-reload Timer PWM Function
COUNTER
255
COMPARE
VALUE
RELOAD
REGISTER
000
t
PWM OUTPUT
t
VR001852
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ST62T28C/E28C
AUTO-RELOAD TIMER (Cont’d)
Capture Mode with PWM Generation. In this
mode, the AR counter operates as a free running
8-bit counter fed by the prescaler output. The
counter is incremented on every clock rising edge.
An 8-bit capture operation from the counter to the
ARRC register is performed on every active edge
on the ARTIMin pin, when enabled by Edge Control bits SL0, SL1 in the ARSC1 register. At the
same time, the External Flag, EF, in the ARSC0
register is set and an external interrupt request is
generated if the External Interrupt Enable bit, EIE,
in the ARMC register, is set. The EF flag must be
reset by user software.
Each ARTC overflow sets ARTIMout, while a
match between the counter and ARCP (Compare
Register) resets ARTIMout and sets the compare
flag, CPF. A compare interrupt request is generated if the related compare interrupt enable bit,
CPIE, is set. A PWM signal is generated on ARTIMout. The CPF flag must be reset by user software.
The frequency of the generated signal is determined by the prescaler setting. The duty cycle is
determined by the ARCP register.
Initialization and reading of the counter are identical to the auto-reload mode (see previous description).
Enabling and selection of clock sources is controlled by the CC0 and CC1 bits in the AR Status Control Register, ARSC1.
The prescaler division ratio is selected by programming the PS0, PS1 and PS2 bits in the
ARSC1 Register.
In Capture mode, the allowed clock sources are
the internal clock and the internal clock divided by
3; the external ARTIMin input pin should not be
used as a clock source.
Capture Mode with Reset of counter and prescaler, and PWM Generation. This mode is identical to the previous one, with the difference that a
capture condition also resets the counter and the
prescaler, thus allowing easy measurement of the
time between two captures (for input period measurement on the ARTIMin pin).
Load on External Input. The counter operates as
a free running 8-bit counter fed by the prescaler.
the count is incremented on every clock rising
edge.
Each counter overflow sets the ARTIMout pin. A
match between the counter and ARCP (Compare
Register) resets the ARTIMout pin and sets the
compare flag, CPF. A compare interrupt request is
generated if the related compare interrupt enable
bit, CPIE, is set. A PWM signal is generated on
ARTIMout. The CPF flag must be reset by user
software.
Initialization of the counter is as described in the
previous paragraph. In addition, if the external ARTIMin input is enabled, an active edge on the input
pin will copy the contents of the ARRC register into
the counter, whether the counter is running or not.
Notes:
The allowed AR Timer clock sources are the following:
AR Timer Mode
Auto-reload mode
Capture mode
Capture/Reset mode
External Load mode
fINT,
fINT,
fINT,
fINT,
Clock Sources
fINT/3, ARTIMin
fINT/3
fINT/3
fINT/3
The clock frequency should not be modified while
the counter is counting, since the counter may be
set to an unpredictable value. For instance, the
multiplexer setting should not be modified while
the counter is counting.
Loading of the counter by any means (by auto-reload, through ARLR, ARRC or by the Core) resets
the prescaler at the same time.
Care should be taken when both the Capture interrupt and the Overflow interrupt are used. Capture
and overflow are asynchronous. If the capture occurs when the Overflow Interrupt Flag, OVF, is
high (between counter overflow and the flag being
reset by software, in the interrupt routine), the External Interrupt Flag, EF, may be cleared simultaneusly without the interrupt being taken into account.
The solution consists in resetting the OVF flag by
writing 06h in the ARSC0 register. The value of EF
is not affected by this operation. If an interrupt has
occured, it will be processed when the MCU exits
from the interrupt routine (the second interrupt is
latched).
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ST62T28C/E28C
AUTO-RELOAD TIMER (Cont’d)
4.3.3 AR Timer Registers
AR Mode Control Register (ARMC)
Address: E5h — Read/Write
Reset status: 00h
7
TCLD
0
TEN
PWMOE
EIE
CPIE
OVIE ARMC1 ARMC0
ARSC0 register is also set, an interrupt request is
generated.
Bit 1-0 = ARMC1-ARMC0: Mode Control Bits 1-0.
These are the operating mode control bits. The following bit combinations will select the various operating modes:
ARMC1
0
0
ARMC0
0
1
1
0
1
1
The AR Mode Control Register ARMC is used to
program the different operating modes of the AR
Timer, to enable the clock and to initialize the
counter. It can be read and written to by the Core
and it is cleared on system reset (the AR Timer is
disabled).
Bit 7 = TLCD: Timer Load Bit. This bit, when set,
will cause the contents of ARRC register to be
loaded into the counter and the contents of the
prescaler register, ARPSC, are cleared in order to
initialize the timer before starting to count. This bit
is write-only and any attempt to read it will yield a
logical zero.
Bit 6 = TEN: Timer Clock Enable. This bit, when
set, allows the timer to count. When cleared, it will
stop the timer and freeze ARPSC and ARTSC.
Bit 5 = PWMOE: PWM Output Enable. This bit,
when set, enables the PWM output on the ARTIMout pin. When reset, the PWM output is disabled.
Bit 4 = EIE: External Interrupt Enable. This bit,
when set, enables the external interrupt request.
When reset, the external interrupt request is
masked. If EIE is set and the related flag, EF, in
the ARSC0 register is also set, an interrupt request is generated.
Bit 3 = CPIE: Compare Interrupt Enable. This bit,
when set, enables the compare interrupt request.
If CPIE is reset, the compare interrupt request is
masked. If CPIE is set and the related flag, CPF, in
the ARSC0 register is also set, an interrupt request is generated.
Bit 2 = OVIE: Overflow Interrupt. This bit, when
set, enables the overflow interrupt request. If OVIE
is reset, the compare interrupt request is masked.
If OVIE is set and the related flag, OVF in the
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Operating Mode
Auto-reload Mode
Capture Mode
Capture Mode with Reset
of ARTC and ARPSC
Load on External Edge
Mode
AR Timer Status/Control Registers ARSC0 &
ARSC1. These registers contain the AR Timer status information bits and also allow the programming of clock sources, active edge and prescaler
multiplexer setting.
ARSC0 register bits 0,1 and 2 contain the interrupt
flags of the AR Timer. These bits are read normally. Each one may be reset by software. Writing a
one does not affect the bit value.
AR Status Control Register 0 (ARSC0)
Address: E6h — Read/Clear
7
D7
0
D6
D5
D4
D3
EF
CPF
OVF
Bits 7-3 = D7-D3: Unused
Bit 2 = EF: External Interrupt Flag. This bit is set by
any active edge on the external ARTIMin input pin.
The flag is cleared by writing a zero to the EF bit.
Bit 1 = CPF: Compare Interrupt Flag. This bit is set
if the contents of the counter and the ARCP register are equal. The flag is cleared by writing a zero
to the CPF bit.
Bit 0 = OVF: Overflow Interrupt Flag. This bit is set
by a transition of the counter from FFh to 00h
(overflow). The flag is cleared by writing a zero to
the OVF bit.
ST62T28C/E28C
AUTO-RELOAD TIMER (Cont’d)
AR Status Control Register 1(ARSC1)
Address: E7h — Read/Write
7
0
PS2
PS1
PS0
D4
SL1
SL0
CC1
CC0
Bist 7-5 = PS2-PS0: Prescaler Division Selection
Bits 2-0. These bits determine the Prescaler division ratio. The prescaler itself is not affected by
these bits. The prescaler division ratio is listed in the
following table:
Table 16. Prescaler Division Ratio Selection
PS2
0
PS1
0
PS0
0
ARPSC Division Ratio
1
0
0
1
2
0
1
0
4
0
1
1
8
1
0
0
16
1
0
1
32
1
1
0
64
1
1
1
128
Bit 4 = D4: Reserved. Must be kept reset.
Bit 3-2 = SL1-SL0: Timer Input Edge Control Bits 10. These bits control the edge function of the Timer
input pinfor external synchronization. If bit SL0 is reset, edge detection is disabled; if set edge detection
is enabled. If bit SL1 is reset, the AR Timer input pin
is rising edge sensitive; if set, it is falling edge sensitive.
SL1
X
0
1
SL0
0
1
1
Edge Detection
Disabled
Rising Edge
Falling Edge
Bit 1-0 = CC1-CC0: Clock Source Select Bit 1-0.
These bits select the clock source for the AR Timer
through the AR Multiplexer. The programming of
the clocksources is explained in the following Table
17:
AR Load Register ARLR. The ARLR load register
is used to read or write the ARTC counter register
“on the fly” (while it is counting). The ARLR register is not affected by system reset.
AR Load Register (ARLR)
Address: EBh — Read/Write
7
D7
0
D6
D5
D4
D3
D2
D1
D0
Bit 7-0 = D7-D0: Load Register Data Bits. These
are the load register data bits.
AR Reload/Capture Register. The ARRC reload/
capture register is used to hold the auto-reload
value which is automatically loaded into the counter when overflow occurs.
AR Reload/Capture (ARRC)
Address: E9h — Read/Write
7
D7
0
D6
D5
D4
D3
D2
D1
D0
Bit 7-0 = D7-D0: Reload/Capture Data Bits. These
are the Reload/Capture register data bits.
AR Compare Register. The CP compare register
is used to hold the compare value for the compare
function.
AR Compare Register (ARCP)
Address: EAh — Read/Write
7
D7
0
D6
D5
D4
D3
D2
D1
D0
Bit 7-0 = D7-D0: Compare Data Bits. These are
the Compare register data bits.
Table 17. Clock Source Selection.
CC1
0
0
1
1
CC0
0
1
0
1
Clock Source
Fint
Fint Divided by 3
ARTIMin Input Clock
Reserved
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ST62T28C/E28C
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 typical conversion time of 70us (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. This interrupt is associated with interrupt vector #4 and 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
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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 29. 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).
ST62T28C/E28C
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 (V DD 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 SS
--------------------------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.
One extra feature is available in the ADC to get a
better accuracy. In fact, each ADC conversion has
to be followed by a WAIT instruction to minimize
the noise during the conversion. But the first conversion step is performed before the execution of
the WAIT when most of clocks signals are still enabled . The key is to synchronize the ADC start
with the effective execution of the WAIT. This is
achieved by setting ADC SYNC option. This way,
ADC conversion starts in effective WAIT for maximum accuracy.
Note: With this extra option, it is mandatory to execute WAIT instruction just after ADC start instruction. Insertion of any extra instruction may cause
spurious interrupt request at ADC interrupt vector.
A/D Converter Control Register (ADCR)
Address: 0D1h — Read/Write
7
EAI
0
EOC
STA
PDS
CLSEL
OSC
OFF
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= 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 2 = OSCOFF. When low, this bit enables main
oscillator to run. The main oscillator is switched off
when OSCOFF is high.
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.
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ST62T28C/E28C
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 76,800 Baud with an 8MHz external oscillator) and flexible character formats.
Operating in Half-Duplex mode only, the UART
uses a 10-bit frame or a 11-bit frame according to
the choosen MCU option. Automatic parity bit generation is software selectable in the 10-bit character format allowing either 7 data bit + 1 parity bit, or
8 data bit transmission. 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 isalso available in WAIT mode of the 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).
In the 11-bit character format option, 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 30. UART Block Diagram
START
DETECTOR
RXD1
UARTOE
TXD
DIN
DATA SHIFT
1
DOUT
MUX
REGISTER
DR
D8 D7 D6 D5 D4 D3 D2 D1 D0
TXD1
0
CONTROL LOGIC
TO CORE
WRIT E
READ
RECEIV E BUFFER
REGISTER
CONTROL REGIST ER
BAUD RATE
D8
RX and TX
INTE RRUPTS
PROGRAMMABLE
DIVIDE R
fOSC
BAUD RATE x 8
VR02009
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52
ST62T28C/E28C
U. A. R. T (Cont’d)
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 19. 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
Whatever the format selected as MCU option, 10bit or 11-bit frame, the start and stop bit are automatically generated by the UART. Only the remaining 8 (Resp. 9) bit in the 10-bit (Resp. 11-bit)
frame are under control of the user.
Transmission is started by writing the Data Register, after having previously set the transmission
software options, the baudrate and the parity enable. In case of 11-bit frame, the 9th bit must then
be set before into the LSB of the UART Control
Register. 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 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 data bit with the
Figure 31. 11-bit Character Format Example
LSB D0 at first.. 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.
4.5.3.1 Character Format
Once the MCU option is set as 10-bit or 11-bit
frame, the frame length is fixed. Within these 8 or 9
remaining bit, any format can be used as shown in
the Table 18. Only the even parity automatic computation in the 10-bit frame is available. Any other
parity bit can however be software computed and
processed as a data bit
Table 18. Character Options
Start Bit
Start Bit
Start Bit
8 Data
7 Data
7 Data
Start
Start
Start
Start
8
9
8
7
Bit
Bit
Bit
Bit
Data
Data
Data
Data
10 bit frame
No Parity
1 Even Parity (Auto)
1 Software Parity
11 bit frame
1 Software Parity
No Parity
No Parity
1 Software Parity
1 Stop
1 Stop
1 Stop
1 Stop
1 Stop
2 Stop
2 Stop
Figure 32. UART Data Output
UARTOE
START
BIT
STOP
BIT
TXD
1
D0 D1
BIT
POSITION
1
2
START OF DATA
D7 D8
8
9
MUX
10
POSSIBLE
NEXT
CHARACTER
START
PORT DATA
OUTPU T
TXD1
0
VR02011
VR02012
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ST62T28C/E28C
U. A. R. T (Cont’d)
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. First 8 bit are stored into the UART
Data Register, while the additionnal 9th bit is
stored into the LSB of the UART Control Register
in case of the 11-bit frame MCU option has been
selected. When the 10-bit frame option is selected,
the parity of the 8 received bit is automatically written into the LSB of the UART Control Register
(PTYEN bit).
After all bit 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.
1 BIT
1
2
3
4
5
6
SAMPLES
7
7
D7
0
D6
D5
D4
D3
D2
D1
8
VR02010
Table 19. Baudrate Selection
BR2
BR1
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
104
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54
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. If the automatic even parity computation is
set (Bit PTYEN set), D7 must be cleared to 0 before transmission. Only the 7 LSB D0..D6 contain
the data to be sent.
Warning. No Read/Write Instructions may be
used with this register as both transmit and receive
share the same address
Figure 33. Data Sampling Points
0
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.
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
Baud Rate
f INT = 8MHz
1200
2400
4800
9600
19200
31200
38400
76800
f INT = 4MHz
600
1200
2400
4800
9600
15600
19200
38400
ST62T28C/E28C
U. A. R. T (Cont’d)
UART Control Register (UARTCR)
Address: D7h, Read/Write
7
RXRDY TXMT RXIEN TXIE N
0
BR2
BR1
BR0
PTYEN
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.
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 = PTYEN. Parity/Data Bit 8. The function of
this bit depens on the MCU option set. In 11-bit
frame mode, it is the 9th bit of the trasmitted/received character. In 10-bit frame mode, writing a 1
enables the automatic even parity computation,
while a read instruction after reception gives the
parity of the whole 8 bit word received. For the
even parity, a 0 value means no parity error.
Note: As the PTYEN bit is modified in reception, it
must be to set to 1 before transmission if a reception occured in between.
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ST62T28C/E28C
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 output
operation Sout has to be programmed as opendrain 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 34 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.
WARNING: In all cases, in both slave and master
mode, the SCL pin must always be configured as
input (Reset state).
In master mode, the SCL signal must be generated by software and output on another free I/O port
pin which must be connected externally to the SCL
input pin.
Figure 34. 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
Q4
RESET
4-Bit Counter
Q4
(Q4=High after Clock8)
Sin
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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ST62T28C/E28C
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.
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.
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ST62T28C/E28C
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
58/84
58
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.
ST62T28C/E28C
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 20. Load & Store Instructions
Instruction
LD
LD
LD
LD
LD
A, X
A, Y
A, V
A, W
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
Addressing Mode
Bytes
Cycles
Direct
Direct
Direct
Direct
Direct
1
1
1
1
1
Short Direct
Short Direct
Short Direct
Direct
Direct
Indirect
Indirect
Indirect
Indirect
Immediate
Immediate
1
1
1
2
2
1
1
1
1
2
3
Short
Short
Short
Short
Short
Flags
4
4
4
4
4
Z
∆
∆
∆
∆
∆
C
*
*
*
*
*
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
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ST62T28C/E28C
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 21. 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
Notes:
X,Y.Indirect Register Pointers, V & W Short Direct RegistersD. Affected
# . Immediate data (stored in ROM memory)* . Not Affected
rr. Data space register
60/84
60
Flags
Z
∆
∆
∆
∆
∆
∆
∆
∆
∆
*
∆
∆
∆
∆
∆
∆
∆
∆
∆
∆
∆
∆
∆
∆
∆
∆
∆
∆
∆
∆
∆
∆
∆
∆
∆
∆
∆
C
∆
∆
∆
∆
∆
∆
∆
∆
∆
*
∆
∆
∆
∆
∆
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
∆
∆
∆
∆
∆
∆
ST62T28C/E28C
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 22. 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 23. 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 24. 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 25. Jump & Call Instructions
Instruction
CALL abc
JP abc
Addressing Mode
Extended
Extended
Bytes
Cycles
2
2
4
4
Flags
Z
C
*
*
*
*
Notes:
abc. 12-bit address;
* . Not Affected
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61
ST62T28C/E28C
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
Abbreviations 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
62/84
62
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 Ill egal 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
Addressing Mode
AND
a,(x)
ind
ANDI
a,nn
imm
SUB
a,(x)
ind
SUBI
a,nn
imm
DEC
(x)
ind
2
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
e
1
1
0001
#
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
prc
ST62T28C/E28C
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
Abbreviations 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
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 Ill egal 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
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
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
e
1
prc
Addressing Mode
63/84
63
ST62T28C/E28C
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 V DD.
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)
V
V
VI
Input Voltage
V SS - 0.3 to VDD + 0.3
VO
Output Voltage
V SS - 0.3 to VDD + 0.3 (1)
80
mA
100
mA
150
°C
-60 to 150
°C
IV DD
Total Current into VDD (source)
IVSS
Total Current out of VSS (sink)
Junction Temperature
Tj
TSTG
Storage Temperature
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 periods 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.
64/84
64
ST62T28C/E28C
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
f OSC = 4MHz, 1 & 6 Suffix
f OSC = 4MHz, 3 Suffix
fosc= 8MHz , 1 & 6 Suffix
fosc= 8MHz , 3 Suffix
3.0
3.0
3.6
4.5
6.0
6.0
6.0
6.0
V
0
0
0
0
4.0
4.0
8.0
4.0
MHz
V DD =
V DD =
V DD =
V DD =
2)
3.0V, 1 & 6 Suffix
3.0V , 3 Suffix
3.6V , 1 & 6 Suffix
3.6V , 3 Suffix
fOSC
Oscillator Frequency
IINJ+
Pin Injection Current (positive)
V DD = 4.5 to 5.5V
+5
mA
IINJ-
Pin Injection Current (negative) V DD = 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 35. Maximum Operating FREQUENCY (Fmax) Versus SUPPLY VOLTAGE (VDD)
Maximum FREQU ENCY (MHz)
1 & 6 Suffix version
8
FUNCTIONALITY IS NOT
3 Suffix version
GUARANTEED IN
7
THIS AREA
6
5
4
3
2
1
2.5
3
3.6
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.
65/84
65
ST62T28C/E28C
6.3 DC ELECTRICAL CHARACTERISTICS
(TA = -40 to +125°C unless otherwise specified)
Symbol
VIL
VIH
V Hys
Vup
V dn
VOL
VOH
R PU
IIL
IIH
IDD
Retention
Parameter
Input Low Level Voltage
All Input pins
Input High Level Voltage
All Input pins
Hysteresis Voltage (1)
All Input pins
66
Value
Min.
Typ.
Max.
VDD x 0.3
VDD= 5V
VDD= 3V
LVD Threshold in power-on
LVD threshold in powerdown
Low Level Output Voltage
VDD= 5.0V; IOL = +10µA
All Output pins
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; IOH = -10µA
All Output pins
VDD= 5.0V; IOH = -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
VIN = VDD
RESET pin
Supply Current in RESET
VRESET=VSS
Mode
fOSC=8MHz
Supply Current in
VDD=5.0V fINT=8MHz
RUN Mode (2)
Supply Current in WAIT
VDD=5.0V fINT=8MHz
Mode (3)
Supply Current in STOP
ILOAD=0mA
Mode, with LVD disabled(3) VDD=5.0V
Supply Current in STOP
ILOAD=0mA
Mode, with LVD enabled(3) VDD=5.0V
EPROM Data Retention
TA = 55°C
Notes:
(1) Hysteresis voltage between switching levels
(2) All peripherals running
(3) All peripherals in stand-by
66/84
Test Conditions
Unit
V
VDD x 0.7
V
0.2
0.2
V
3.5
4.1
3.8
4.3
0.1
0.8
0.1
0.8
1.3
4.9
3.5
40
150
-8
V
V
100
350
350
900
0.1
1.0
-16
-30
10
ΚΩ
µA
7.0
mA
7.0
mA
1.5
mA
20
µA
500
10
years
ST62T28C/E28C
DC ELECTRICAL CHARACTERISTICS (Cont’d)
(TA = -40 to +85°C unless otherwise specified))
Symbol
Parameter
Vup
V dn
LVD Threshold in power-on
LVD threshold in powerdown
Low Level Output Voltage
All Output pins
VOL
Low Level Output Voltage
20 mA Sink I/O pins
VOH
IDD
High Level Output Voltage
All Output pins
Supply Current in STOP
Mode, with LVD disabled(*)
Test Conditions
VDD= 5.0V; IOL = +10µA
VDD= 5.0V; IOL = + 5mA
VDD= 5.0V; IOL = + 10mAv
VDD= 5.0V; IOL = +10µA
VDD= 5.0V; IOL = +10mA
VDD= 5.0V; IOL = +20mA
VDD= 5.0V; IOL = +30mA
VDD= 5.0V; IOH = -10µA
VDD= 5.0V; IOH = -5.0mA
ILOAD=0mA
VDD=5.0V
Value
Min.
Typ.
Max.
Vdn +50 mV
3.6
4.1
3.8
4.3
Vup -50 mV
0.1
0.8
1.2
0.1
0.8
1.3
2.0
4.9
3.5
Unit
V
V
V
V
µA
10
Note:
(*) All Peripherals in stand-by.
6.4 AC ELECTRICAL CHARACTERISTICS
(TA = -40 to +125°C unless otherwise specified)
Symbol
Parameter
Test Conditions
Value
Min.
tREC
Supply Recovery Time (1)
100
fLFAO
Internal frequency with LFAO active
200
fOSG
Internal Frequency with OSG
enabled 2)
VDD = 3V
VDD = 3.6V
VDD = 4.5V
VDD = 6V
Unit
Typ.
Max.
400
800
kHz
fOSC
MHz
5.8
3.5
900
MHz
MHz
kHz
ms
1
1
2
2
fRC
VDD=5.0V
Internal frequency with RC oscillator R=47kΩ
R=100kΩ
and OSG disabled 2) 3)
R=470kΩ
CIN
Input Capacitance
All Inputs Pins
10
pF
Output Capacitance
All Outputs Pins
10
pF
C OUT
4
2.7
800
5
3.2
850
Notes:
1. Period for which VDD has to be connected at 0V to allow internal Reset function at next power-up.
2 An oscillator frequency above 1MHz is recommended for reliable A/D results.
3. Measure performed with OSCin pin soldered on PCB, with an around 2pF equivalent capacitance.
67/84
67
ST62T28C/E28C
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
ACIN
Value
Typ.
8
Min.
Resolution
ZIR
AD I
Test Conditions
fOSC > 1.2MHz
fOSC > 32kHz
fOSC = 8MHz (TA < 85°C)
fOSC = 4 MHz
Conversion result when
VIN = VSS
Conversion result when
VIN = VDD
Max.
Unit
Bit
±2
±4
70
140
LSB
µs
00
Hex
Analog Input Current During
VDD= 4.5V
Conversion
Analog Input Capacitance
2
FF
Hex
1.0
µA
5
pF
Notes:
1. Noise at VDD, VSS <10mV
2. With oscillator frequencies less than 1MHz, the A/D Converter accuracy is decreased.
6.6 TIMER CHARACTERISTICS
(TA = -40 to +125°C unless otherwise specified)
Symbol
Parameter
fIN
Input Frequency on TIMER Pin
tW
Pulse Width at TIMER Pin
Test Conditions
VDD = 3.0V
VDD >4.5V
(TA = -40 to +125°C unless otherwise specified)
6.8 ARTIMER ELECTRICAL CHARACTERISTICS
68/84
Value
Typ.
Max.
IINT
---------4
6.7 SPI CHARACTERISTICS
(TA = -40 to +125°C unless otherwise specified)
Min.
1
125
Unit
MHz
µs
ns
ST62T28C/E28C
Figure 36.. RC frequency versus Vcc
Frequency
10
R=47K
]
+
0
R=100K
1
R=470K
0.1
3
3.5
4
4.5
VDD (volts)
5
5.5
6
Figure 37. LVD thresholds versus temperature
69/84
ST62T28C/E28C
Idd WAIT (mA)
Figure 38. Idd WAIT versus Vcc at 8 Mhz for OTP devices
1.2
1
0.8
0.6
0.4
0.2
0
T = -40°C
T = 25°C
T = 95°C
T = 125°C
3V
4V
5V
6V
Vdd
This curves represents typical variations and is given for guidance only
Idd WAIT (µA)
Figure 39. Idd STOP versus Vcc for OTP devices
8
6
4
2
0
-2
T = -40°C
T = 25°C
T = 95°C
T = 125°C
3V
4V
5V
6V
Vdd
This curves represents typical variations and is given for guidance only
Figure 40. Idd STOP versus Vcc for ROM devices
Idd STOP (µA)
2
1.5
T = -40°C
T = 25°C
T = 95°C
T = 125°C
1
0.5
0
-0.5
3V
4V
5V
6V
Vdd
This curves represents typical variations and is given for guidance only
70/84
70
ST62T28C/E28C
Idd WAIT (mA)
Figure 41. Idd WAIT versus Vcc at 8Mhz for ROM devices
0.8
T=
T=
T=
T=
0.6
0.4
0.2
-40°C
25°C
95°C
125°C
0
3V
4V
5V
6V
Vdd
This curves represents typical variations and is given for guidance only
Figure 42. Idd RUN versus Vcc at 8 Mhz for ROM and OTP devices
Idd RUN (mA)
8
6
T = -40°C
T = 25°C
4
T = 95°C
T = 125°C
2
0
3V
4V
5V
6V
Vdd
This curves represents typical variations and is given for guidance only
Figure 43. Vol versus Iol on all I/O port at Vdd=5V
8
Vol (V)
6
T = -40°C
T = 25°C
T = 95°C
T = 125°C
4
2
0
0
10
20
Iol (mA)
30
40
This curves represents typical variations and is given for guidance only
71/84
71
ST62T28C/E28C
Figure 44. Vol versus Iol on all I/O port at T=25°C
Vol (V)
8
Vdd
Vdd
Vdd
Vdd
6
4
2
= 3.0V
= 4.0V
= 5.0V
= 6.0V
0
0
10
20
Iol (mA)
30
40
This curves represents typical variations and is given for guidance only
Figure 45. Vol versus Iol for High sink (20mA) I/Oports at T=25°C
5
Vol (V)
4
Vdd
Vdd
Vdd
Vdd
3
2
1
= 3.0V
= 4.0V
= 5.0V
= 6.0V
0
0
10
20
Iol (mA)
30
40
Figure 46. Vol versus Iol for High sink (20mA) I/O ports at Vdd=5V
5
Vol (V)
4
T=
T=
T=
T=
3
2
1
0
0
10
20
Iol (mA)
30
This curves represents typical variations and is given for guidance only
72/84
72
40
-40°C
25°C
95°C
125°C
ST62T28C/E28C
Figure 47. Voh versus Ioh on all I/O port at 25°C
Voh (V)
6
Vdd
Vdd
Vdd
Vdd
4
2
0
= 3.0V
= 4.0V
= 5.0V
= 6.0V
-2
0
10
20
Ioh (mA)
30
40
Figure 48. Voh versus Ioh on all I/O port at Vdd=5V
6
Voh (V)
4
T=
T=
T=
T=
2
0
-40°C
25°C
95°C
125°C
-2
0
10
20
Ioh (mA)
30
40
This curves represents typical variations and is given for guidance only
73/84
73
ST62T28C/E28C
7 GENERAL INFORMATION
7.1 PACKAGE MECHANICAL DATA
Figure 49. 28-Pin Plastic Dual In-Line Package, 600-mil Width
Dim.
mm
Min
Typ
A
inches
Max
Min
Typ
6.35
Max
0.250
A1
0.38
0.015
A2
3.18
4.95 0.125
0.195
B
0.36
0.56 0.014
0.022
B1
0.76
1.78 0.030
0.070
C
0.20
0.38 0.008
0.015
D
39.75
e
1.565
2.54
eA
0.100
15.24
0.600
E1
12.32
14.73 0.485
0.580
L
2.92
5.08 0.115
0.200
e3
PDIP28
e4
Number of Pins
N
28
Figure 50. 28-Pin Ceramic Side-Brazed Dual In-Line Package
Dim.
mm
Min
Typ
A
Min
Typ
4.17
0.76
B
0.36 0.46 0.56 0.014 0.018 0.022
B1
0.76 1.27 1.78 0.030 0.050 0.070
0.030
C
0.20 0.25 0.38 0.008 0.010 0.015
D
34.95 35.56 36.17 1.376 1.400 1.424
E1
33.02
1.300
14.61 15.11 15.62 0.575 0.595 0.615
e
2.54
0.100
G
12.70 12.95 13.21 0.500 0.510 0.520
G1
12.70 12.95 13.21 0.500 0.510 0.520
G2
L
1.14
2.92
0.045
5.08 0.115
0.200
S
1.27
0.050
Ø
8.89
0.350
Number of Pins
N
74/84
74
Max
0.164
A1
D1
CDIP28W
inches
Max
28
ST62T28C/E28C
PACKAGE MECHANICAL DATA (Cont’d)
Figure 51. 28-Pin Plastic Small Outline Package, 300-mil Width
Dim.
mm
Min
Typ
inches
Max
Min
Typ
Max
A
2.35
2.65 0.0926
0.1043
A1
0.10
0.30 0.0040
0.0118
B
0.33
0.51
0.013
0.020
C
0.23
0.32 0.0091
0.0125
D
17.70
18.10 0.6969
0.7125
E
7.40
7.60 0.2914
0.2992
e
1.27
0.0500
H
10.01
10.64 0.394
0.419
h
0.25
0.74
0.029
0.010
K
L
0.41
1.27
G
0°
8°
0.016
0.050
0.10
SO28
0.004
Number of Pins
N
28
Figure 52. 28-Pin Plastic Shrink Small Outline Package, 0.209” Width
Dim.
mm
Min
Typ
Max
1.73 1.86
1.99 0.068
0.073
0.078
A1
0.05 0.13
0.21 0.002
0.005
0.008
B
0.25
0.38 0.010
C
0.09
0.20 0.004
D
10.07 10.20 10.33 0.396
0.402
0.407
E
7.65 7.80
7.90 0.301
0.307
0.311
E1
5.20 5.30
5.38 0.205
0.209
0.212
K
L
Max
Min
0.65
G
SSOP28
inches
A
e
Typ
4°
0.63 0.75
0.008
0.026
0.076
0°
0.015
0.003
8°
0°
0.95 0.025
4°
8°
0.030
0.037
Number of Pins
N
28
75/84
75
ST62T28C/E28C
THERMAL CHARACTERISTIC
Symbol
RthJA
Parameter
Test Conditions
Thermal Resistance
Value
Min.
Typ.
Max.
PDIP28
70
PSO28
70
Unit
°C/W
7.2 ORDERING INFORMATION
Table 26. OTP/EPROM VERSION ORDERING INFORMATION
Sales Type
ST62E28CF1
Program
Memory (Bytes)
I/O
Temperature Range
Package
7948 (EPROM)
0 to 70°C
CDIP28W
7948 (OTP)
-40 to 85°C
ST62T28CB6
ST62T28CM6
PDIP28
20
ST62T28CN6
ST62T28CB3
ST62T28CM3
ST62T28CN3
76/84
76
PSO28
SSOP28
PDIP28
7948 (OTP)
-40 to +125°C
PSO28
SSOP28
ST62P28C
8-BIT MCUs WITH A/D CONVERTER, AUTO-RELOAD
TIMER, UART, OSG, SAFE RESET AND 28-PIN PACKAGE
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
20 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
8 I/O lines can sink up to 20mA to drive LEDs or
TRIACs directly
8-bit Timer/Counter with 7-bit programmable
prescaler
8-bit Auto-reload Timer with 7-bit programmable
prescaler (AR Timer)
Digital Watchdog
8-bit A/D Converter with 12 analog inputs
8-bit Asynchronous Peripheral Interface
(UART)
8-bit Synchronous Peripheral Interface (SPI)
On-chip Clock oscillator can be driven by Quartz
Crystal, Ceramic resonator or RC Network
Oscillator Safe Guard
Low Voltage Detector for safe Reset
One external Non-Maskable Interrupt
ST623x-EMU2 Emulation and Development
System (connects to an MS-DOS PC via a
parallel port).
PDIP28
PS028
SS0P28
(See end of Datasheet for Ordering Information)
DEVICE SUMMARY
DEVICE
ST62P28C
ROM
(Bytes)
7948
I/O Pins
20
Rev. 2.8
November 1999
77/84
77
ST62P28C
1 GENERAL DESCRIPTION
1.1 INTRODUCTION
The ST62P28C are the Factory Advanced Service
Technique ROM (FASTROM) versions of
ST62T18C 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
The following section deals with the procedure for
transfer of customer codes to STMicroelectronics.
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 STMicroelectronics using the correctly filled OPTION
LIST appended.
1.2.2 Listing Generation and Verification
When STMicroelectronics receives the user’s
ROM contents, a computer listing is generated
from it. 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 STMicroelectronics. The
signed listing forms a part of the contractual agreement for the production of the specific customer
MCU.
The STMicroelectronics Sales Organization will be
pleased to provide detailed information on contractual points.
Table 1. ROM Memory Map for ST62P28C
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
ST62P28CB1/XXX
ST62P28CB6/XXX
ST62P28CB3/XXX(*)
ST62P28CM1/XXX
ST62P28CM6/XXX
ST62P28CM3/XXX(*)
ST62P28CN1/XXX
ST62P28CN6/XXX
ST62P28CN3/XXX(*)
(*) Advanced information
78/84
78
ROM
7948
I/O
20
Temperature Range
Package
0 to +70°C
-40 to 85°C
-40 to + 125°C
PDIP28
0 to +70°C
-40 to 85°C
-40 to + 125°C
PSO28
0 to +70°C
-40 to 85°C
-40 to + 125°C
SSOP28
ST62P28C
ST62P28C MICROCONTROLLER OPTION LIST
Customer
Address
.. .. . .... . ... .. .. ... ... . ... .. .. .. .. . .. .. .. . . .... . ... .. .
.. .. . .... . ... .. .. ... ... . ... .. .. .. .. . .. .. .. . . .... . ... .. .
Contact
Phone No
Reference
.. .. . .... . ... .. .. ... ... . ... .. .. .. .. . .. .. .. . . .... . ... .. .
.. .. . .... . ... .. .. ... ... . ... .. .. .. .. . .. .. .. . . .... . ... .. .
.. .. . .... . ... .. .. ... ... . ... .. .. .. .. . .. .. .. . . .... . ... .. .
STMicroelectronics references
Device:
Package:
[ ] ST62P28C
[ ] Dual in Line Plastic
[ ] Small Outline Plastic
[ ] Tape & Reel
[ ] Stick (Default)
[ ] Shrink Small Outline Plastic
Temperature Range:
[ ] 0°C to + 70°C
[ ] - 40°C to + 85°C[ ] - 40°C to + 125°C
Special Marking:
[ ] No
[ ] Yes ”_ _ _ _ _ _ _ _ _ _ _ ”
Authorized characters are letters, digits, ’.’, ’-’, ’/’ and spaces only.
Maximum character count:
PDIP28: 10
PSO28: 8
Oscillator Source Selection: [ ] Crystal Quartz/Ceramic resonator
[ ] RC Network
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
.. .. . .... . ... .. .. ... ... . .
79/84
79
ST62P28C
Notes:
80/84
80
ST6228C
8-BIT MCUs WITH A/D CONVERTER, AUTO-RELOAD
TIMER, UART, OSG, SAFE RESET AND 28-PIN PACKAGE
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
20 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
8 I/O lines can sink up to 20mA to drive LEDs or
TRIACs directly
8-bit Timer/Counter with 7-bit programmable
prescaler
8-bit Auto-reload Timer with 7-bit programmable
prescaler (AR Timer)
Digital Watchdog
8-bit A/D Converter with 12 analog inputs
8-bit Asynchronous Peripheral Interface
(UART)
8-bit Synchronous Peripheral Interface (SPI)
On-chip Clock oscillator can be driven by Quartz
Crystal, Ceramic resonator or RC Network
Oscillator Safe Guard
Low Voltage Detector for safe Reset
One external Non-Maskable Interrupt
ST623x-EMU2 Emulation and Development
System (connects to an MS-DOS PC via a
parallel port).
PDIP28
PS028
SS0P28
(See end of Datasheet for Ordering Information)
DEVICE SUMMARY
DEVICE
ST6228C
ROM
(Bytes)
7948
I/O Pins
20
Rev. 2.8
November 1999
81/84
81
ST6228C
1 GENERAL DESCRIPTION
1.1 INTRODUCTION
1.2 ROM READOUT PROTECTION
The ST6228C is mask programmed ROM version
of ST62T28C OTP devices.
They offer the same functionality as OTP devices,
selecting as ROM options the options defined in
the programmable option byte of the OTP version.
If the ROM READOUT PROTECTION option is
selected, a protection fuse can be blown to prevent any access to the program memory content.
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
TEST
0.5s min
5V
15
14V typ
10
47mF
100nF
5
VSS
TEST
VDD
150 µs typ
PROTECT
100mA
max
14V
TEST
100nF
ZPD15
15V
VR02003
4mA typ
t
VR02001
Note: ZPD15 is used for overvoltage protection
82/84
82
ST6228C
ST6228C MICROCONTROLLER OPTION LIST
Customer
Address
.. .. . .... . ... .. .. ... ... . ... .. .. .. .. . .. .. .. . . .... . ... .. .
.. .. . .... . ... .. .. ... ... . ... .. .. .. .. . .. .. .. . . .... . ... .. .
Contact
Phone No
Reference
.. .. . .... . ... .. .. ... ... . ... .. .. .. .. . .. .. .. . . .... . ... .. .
.. .. . .... . ... .. .. ... ... . ... .. .. .. .. . .. .. .. . . .... . ... .. .
.. .. . .... . ... .. .. ... ... . ... .. .. .. .. . .. .. .. . . .... . ... .. .
STMicroelectronics references
Device:
Package:
[ ] ST6228C
[ ] Dual in Line Plastic
[ ] Small Outline Plastic
[ ] Tape & Reel
[ ] Stick (Default)
[ ] Shrink Small Outline Plastic
Temperature Range:
[ ] 0°C to + 70°C
[ ] - 40°C to + 85°C[ ] - 40°C to + 125°C
Special Marking:
[ ] No
[ ] Yes ”_ _ _ _ _ _ _ _ _ _ _ ”
Authorized characters are letters, digits, ’.’, ’-’, ’/’ and spaces only.
Maximum character count:
PDIP28: 10
PSO28: 8
Oscillator Source Selection: [ ] Crystal Quartz/Ceramic resonator
[ ] RC Network
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
.. .. . .... . ... .. .. ... ... . .
83/84
83
ST6228C
1.3 ORDERING INFORMATION
The following section deals with the procedure for
transfer of customer codes to STMicroelectronics.
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
STMicroelectronics using the correctly filled OPTION LIST appended.
1.3.2 Listing Generation and Verification
When STMicroelectronics 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
STMicroelectronics. The signed listing forms a
part of the contractual agreement for the creation
of the specific customer mask.
The STMicroelectronics Sales Organization will be
pleased to provide detailed information on contractual points.
Table 1. ROM Memory Map for ST6228C
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
ST6228CB1/XXX
ST6228CB6/XXX
ST6228CB3/XXX
ST6228CM1/XXX
ST6228CM6/XXX
ST6228CM3/XXX
ROM
7948
I/O
Temperature Range
Package
0 to +70°C
-40 to 85°C
-40 to + 125°C
PDIP28
0 to +70°C
-40 to 85°C
-40 to + 125°C
PSO28
0 to +70°C
-40 to 85°C
-40 to + 125°C
SSOP28
20
ST6228CN1/XXX
ST6228CN6/XXX
ST6228CN3/XXX
Information furnished is believed to be accurate and reliable. However, STMicroelectronics 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 STMicroelectronics. Specifications mentioned in this publication are subject
to change without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics products are not
authorized for use as critical components in life support devices or systems without the express written approval of STMicroelectronics.
The ST logo is a registered trademark of STMicroelectronics
1999 STMicroelectronics - All Rights Reserved.
Purchase of I2 C Components by STMicroelectronics conveys a license under the Philips I2C Patent. Rights to use these components in an
I2C system is granted provided that the system conforms to the I2C Standard Specification as defined by Philips.
STMicroelectronics Group of Companies
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http:// www.st.com
84/84
84