Laptop User Manual

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 clock signal from 4 different
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 Watchdog
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 Watchdog timer control register 0x8021
WTCON Bit Description Initial State
Prescaler value [15:8] Prescaler value.
The valid range is from 0 to 255(2
8
-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 timer 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