ST10F269-T3 STMicroelectronics, ST10F269-T3 Datasheet - Page 105

• Manufacturer Part Number: ST10F269-T3
• Manufacturer: STMicroelectronics

Specifications of ST10F269-T3

• Cpu Family: ST10
• Device Core Size: 16b
• Frequency (max): 32MHz
• Interface Type: ASC/I2C/SSC
• Program Memory Type: Flash
• Program Memory Size: 256KB
• Total Internal Ram Size: 12KB
• # I/os (max): 111
• Number Of Timers - General Purpose: 4
• Operating Supply Voltage (typ): 5V
• Operating Supply Voltage (max): 5.5V
• Operating Supply Voltage (min): 4.5V
• On-chip Adc: 16-chx10-bit
• Instruction Set Architecture: CISC/RISC
• Operating Temp Range: -40C to 125C
• Operating Temperature Classification: Automotive
• Mounting: Surface Mount
• Pin Count: 144
• Package Type: TQFP
• Lead Free Status / Rohs Status: Supplier Unconfirmed

17 - WATCHDOG TIMER
The Watchdog Timer is a fail-safe mechanism which prevents the microcontroller from malfunctioning for
long periods of time.
The Watchdog Timer is always enabled after a reset of the chip and can only be disabled in the time
interval until the EINIT (end of initialization) instruction has been executed.
Therefore, the chip start-up procedure is always monitored. The software must be designed to service the
watchdog timer before it overflows. If, due to hardware or software related failures, the software fails to do
so, the watchdog timer overflows and generates an internal hardware reset. It pulls the RSTOUT pin low
in order to allow external hardware components to be reset.
Each of the different reset sources is indicated in the WDTCON register.
The indicated bits are cleared with the EINIT instruction. The origin of the reset can be identified during
the initialization phase.
WDTCON (FFAEh / D7h)
Notes: 1. More than one reset indication flag may be set. After EINIT, all flags are cleared.
WDTIN
WDTR
SWR
SHWR
LHWR
PONR
15
1-3
2. Power-on is detected when a rising edge from V
3. These bits cannot be directly modified by software.
1- 2-3
1-3
1-3
1-3
14
13
Watchdog Timer Input Frequency Selection
‘0’: Input Frequency is f
‘1’: Input Frequency is f
Watchdog Timer Reset Indication Flag
Set by the watchdog timer on an overflow.
Cleared by a hardware reset or by the SRVWDT instruction.
Software Reset Indication Flag
Set by the SRST execution.
Cleared by the EINIT instruction.
Short Hardware Reset Indication Flag
Set by the input RSTIN.
Cleared by the EINIT instruction.
Long Hardware Reset Indication Flag
Set by the input RSTIN.
Cleared by the EINIT instruction.
Power-On (Asynchronous) Reset Indication Flag
Set by the input RSTIN if a power-on condition has been detected.
Cleared by the EINIT instruction.
WDTREL
12
RW
11
10
9
CPU
CPU
8
/2.
/128.
DD
= 0 V to V
7
-
SFR
DD
6
-
> 2.0 V is recognized on the internal 2.7V supply.
PONR LHWR SHWR
HR
5
HR
4
HR
3
SWR
HR
Reset Value: 00xxh
2
ST10F269-T3
WDTR WDTIN
HR
1
105/162
RW
0