KS57C2308/P2308/C2316/P2316
TIMERS and TIMER/COUNTERS
11-7
WATCHDOG TIMER MODE REGISTER (WDMOD)
The watchdog timer mode register, WDMOD, is a 8-bit write-only register located at RAM address F98H–F99H.
WDMOD register controls to enable or disable the watchdog function. WDMOD values are set to logic “A5H”
following
RESET
and this value enables the watchdog timer, and watchdog timer is set to the longest interval
because BT overflow signal is generated with the longest interval.
WDMOD
Watchdog Timer Enable/Disable Control
5AH
Disable watchdog timer function
Any other value
Enable watchdog timer function
WATCHDOG TIMER COUNTER (WDCNT)
The watchdog timer counter, WDCNT, is a 3-bit counter. WDCNT is automatically cleared to logic zero, and
restarts whenever the WDTCF register control bit is set to “1”.
RESET,
stop, and wait signal clears the WDCNT to
logic zero also.
WDCNT increments each time a clock pulse of the overflow frequency determined by the current BMOD bit
setting is generated. When WDCNT has incremented to hexadecimal “07H”, it is cleared to “00H” and an
overflow is generated. The overflow causes the system
RESET
. When the interrupt request is generated, BCNT
immediately resumes counting incoming clock signals.
WATCHDOG TIMER COUNTER CLEAR FLAG (WDTCF)
The watchdog timer counter clear flag, WDTCF, is a 1-bit write instruction. When WDTCF is set to one, it clears
the WDCNT to zero and restarts the WDCNT. WDTCF register bits 2–0 are always logic zero.
Table 11-3. Watchdog Timer Interval Time
BMOD
BT Input Clock
(frequency)
WDCNT Input Clock
(frequency)
WDT Interval Time
Main Clock
Sub
Clock
x000b
fxx/2
12
fxx/(2
12
×
2
8)
fxx/2
12
×
2
8
×
2
3
1.75–2 sec
224–256 sec
x011b
fxx/2
9
fxx/(2
9
×
2
8)
fxx/2
9
×
2
8
×
2
3
218.7–250 ms
28–32 sec
x101b
fxx/2
7
fxx/(2
7
×
2
8)
fxx/2
7
×
2
8
×
2
3
54.6–62.5 ms
7–8 sec
x111b
fxx/2
5
fxx/(2
5
×
2
8)
fxx/2
5
×
2
8
×
2
3
13.6–15.6 ms
1.75–2 sec
NOTES:
1.
Clock frequencies assume a system oscillator clock frequency (fxx) of: 4.19 MHz Main clock or 32.768 kHz Sub clock
2.
fxx = system clock frequency.
3.
If the WDMOD changes such as disable and enable, you must set WDTCF flag to “1” for starting WDCNT from zero
state.
Summary of Contents for KS57C2308
Page 30: ...ADDRESS SPACES KS57C2308 P2308 C2316 P2316 2 22 NOTES ...
Page 168: ...SAM47 INSTRUCTION SET KS57C2308 P2308 C2316 P2316 5 94 NOTES ...
Page 170: ......
Page 206: ...POWER DOWN KS57C2308 P2308 C2316 P2316 8 8 NOTES ...
Page 210: ...RESET KS57C2308 P2308 C2316 P2316 9 4 NOTES ...
Page 222: ...I O PORTS KS57C2308 P2308 C2316 P2316 10 12 NOTES ...
Page 272: ...LCD CONTROLLER DRIVER KS57C2308 P2308 C2316 P2316 12 24 NOTES ...
Page 280: ...SERIAL I O INTERFACE KS57C2308 P2308 C2316 P2316 13 8 NOTES ...
Page 294: ...MECHANICAL DATA KS57C2308 P2308 C2316 P2316 15 2 NOTES ...
Page 310: ...KS57P2308 P2316 OTP KS57C2308 P2308 C2316 P2316 16 16 NOTES ...
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