S3C2440A RISC MICROPROCESSOR WATCHDOG TIMER
18-3
WATCHDOG TIMER SPECIAL REGISTERS
WATCHDOG TIMER CONTROL (WTCON) REGISTER
The WTCON register allows the user to enable/disable the watchdog timer, select the c lock s ignal fr om 4 diff erent
sources, enable/disable interrupts, and enable/disable the watchdog timer output.The Watchdog timer is used to
resume the S3C2440A restart on mal-function after its power on; if controller restart is not desired, the W atchdog
timer should be disabled.
If the user wants to use the normal timer provided by the Watchdog timer, enable the interrupt and disable the
Watchdog timer.
Register Address R/W Description Reset Value
WTCON 0x53000000 R/W W atchdog timer control register 0x8021
WTCON Bit Description Initial State
Prescaler value [15:8] Prescaler value.
The valid range is from 0 to 255(28-1). 0x80
Reserved [7:6] Reserved.
These two bits must be 00 in normal operation. 00
Watchdog timer [5] Enable or disable bit of Watchdog timer.
0 = Disable
1 = Enable
1
Clock select [4:3] Determine the clock division factor.
00: 16 01 : 32
10: 64 11 : 128
00
Interrupt generation [2] Enable or disable bit of the interrupt.
0 = Disable
1 = Enable
0
Reserved [1] Reserved.
This bit must be 0 in normal operation. 0
Reset enable/disable [0] Enable or disable bit of Watchdog tim er output for reset
signal.
1: Assert reset signal of the S3C2440A at watchdog time-
out
0: Disable the reset function of the watchdog timer.
1