WATCHDOG TIMER
S3C2416X RISC MICROPROCESSOR
11-2
2 WATCHDOG TIMER OPERATION
2.1 BLOCK DIAGRAM
Figure 11-1 shows the functional block diagram of the watchdog timer. The watchdog timer uses only PCLK as its
source clock. The PCLK frequency is prescaled to generate the corresponding watchdog timer clock, and the
resulting frequency is divided again.
Reset Signal Generator
WTCNT
(Down Counter)
PCLK
WTCON[4:3]
WTDAT
RESET
1/16
1/32
1/64
1/128
8-bit Prescaler
WTCON[15:8]
WTCON[2]
WTCON[0]
Interrupt
MUX
Figure 11-1. Watchdog Timer Block Diagram
The prescaler value and the frequency division factor are specified in the watchdog timer control (WTCON)
register. Valid prescaler values range from 0 to 28-1. The frequency division factor can be selected as 16, 32, 64,
or 128.
Use the following equation to calculate the watchdog timer clock frequency and the duration of each timer clock
cycle:
t_watchdog = 1 / [ PCLK / (Prescaler value + 1) / Division_factor ]
2.2 WTDAT & WTCNT
Watchdog Timer operation based on the value of watchdog timer count (WTCNT) register. Once timer is
operated, count value will be down counting from the initial value of WTCNT register. During the watchdog timer
operation, it contains the current count values.
The value of WDTAT register will be automatically reloaded into WTCNT at every time-out, if watchdog timer is
used for the normal timer.
NOTE
At initial watchdog timer operation(of enable), the value of watchdog timer data (WTDAT) register is not
automatically loaded into the timer counter (WTCNT). An initial value MUST be written to the watchdog
timer count (WTCNT) register, before the watchdog timer starts.
Summary of Contents for S3C2416
Page 122: ...BUS MATRIX EBI S3C2416X RISC MICROPROCESSOR 3 4 NOTES ...
Page 204: ...DMA CONTROLLER S3C2416X RISC MICROPROCESSOR 8 18 NOTES ...
Page 284: ...WATCHDOG TIMER S3C2416X RISC MICROPROCESSOR 11 6 NOTES ...
Page 320: ...REAL TIME CLOCK S3C2416X RISC MICROPROCESSOR 13 16 NOTES ...
Page 344: ...UART S3C2416X RISC MICROPROCESSOR 14 24 NOTES ...
Page 380: ...USB2 0 DEVICE S3C2416X RISC MICROPROCESSOR 16 34 NOTES ...
Page 432: ...2D S3C2416X RISC MICROPROCESSOR 18 38 NOTES ...
Page 446: ...HS_SPI CONTROLLER S3C2416X RISC MICROPROCESSOR 19 14 NOTES ...
Page 604: ...S3C2416X RISC MICROPROCESSOR S3C2416X RISC MICROPROCESSOR 23 22 NOTES ...
Page 638: ...PCM AUDIO INTERFACE S3C2416X RISC MICROPROCESSOR 25 18 NOTES ...
Page 670: ...ELECTRICAL DATA S3C2416X RISC MICROPROCESSOR 26 32 NOTES ...