gc80c510 CORERIVER Semiconductor, gc80c510 Datasheet - Page 52

• Manufacturer Part Number: gc80c510
• Description: Eprom/rom 8-bit Turbo Microcontrollers
• Manufacturer: CORERIVER Semiconductor

WDIF flag each time the timer completes the selected time interval. The WDIF flag is polled to detect a
time-out and the RWT allows software to restart the timer. The Watchdog timer can also be used as a
very long timer. The interrupt feature is enabled in this case. Every time the time-out occurs an interrupt
will occur if the global interrupt enable EA is set.
applications. In case of some power glitches or electro-magnetic interference, the processor may begin
to execute errant code. If this is left unchecked, the entire system may crash. Using the Watchdog timer
interrupt during software development will allow the user to select ideal Watchdog reset locations. The
code is first written without the Watchdog interrupt or reset. Then the Watchdog interrupt is enabled to
identify code locations where interrupt occurs. The user can now insert instructions to reset the
watchdog timer which will allow the code to run without any watchdog timer interrupts. Now the
Watchdog timer reset is enabled and the watchdog interrupt may be disabled. If any errant code is
executed now, then the watchdog timer reset instructions will not be executed at the required instants
and watchdog reset will occur.
The watchdog timer will generate a reset after 256 clocks from after the time-out being occurred.
Table 6-6 Time-out Values for the Watchdog Timer
disable the watchdog timer, but will restart it. In general, software should restart the timer to put it into a
known state.
The main use of the Watchdog timer is as a system monitor. This is important in real-time control
The Watchdog timer will be disabled by a power-on/fail reset. The Watchdog timer reset does not
The default Watchdog time-out is WDT mode 3 (32 x 2
The watchdog time-out selection will result in different time-out values depending on the clock speed.
When used as a simple timer, the reset and interrupt functions are disabled. The timer will set the
Mode
0
1
2
3
WD1
0
0
1
1
WD0
0
1
0
1
Interrupt Time-Out (@4MHz)
132X 2
16 X 2
1 X 2
4 X 2
16
16
16
16
clocks
clocks
clocks
clocks
Page 52 of 211
262.14 ms
524.29 ms
16.38 ms
65.54 ms
16
clocks), which is the shortest time-out period.
16 X 2
32 X 2
1 X 2
4 X 2
Reset Time-Out (@4MHz)
16
16
16
16
+ 256 clocks
+ 256 clocks
+ 256 clocks
+ 256 clocks
Functional Description
262.21 ms
524.35 ms
16.45 ms
65.60 ms