SAF-C502-2R20N Siemens Semiconductor Group, SAF-C502-2R20N Datasheet - Page 28

• Manufacturer Part Number: SAF-C502-2R20N
• Description: 8-Bit CMOS Microcontroller
• Manufacturer: Siemens Semiconductor Group

C502
Fail Safe Mechanisms
The SAB-C502 offers enhanced fail safe mechanisms, which allow an automatic recovery from
software upset or hardware failure.
1) Watchdog Timer (15 bit, WDT)
2) Oscillator Watchdog (OWD)
1) Watchdog Timer (WDT)
The Watchdog Timer in the SAB-C502 is a 15-bit timer, which is incremented by a count rate of
either
f
/2 or
f
/32 (
f
=
f
/12). That is, the machine clock is divided by a series of
CYCLE
CYCLE
CYCLE
OSC
arrangement of two prescalers, a divide-by-two and a divide-by-16 prescaler. The latter is enabled
by setting bit WDTREL.7.
Figure 5 shows the block diagram of the programmable Watchdog Timer.
Figure 5
Block Diagram of the Programmable Watchdog Timer
Semiconductor Group
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