User's Manual

Table Of Contents
WATCHDOG TIMER S3C2450X RISC MICROPROCESSOR
12-4
3 WATCHDOG TIMER SPECIAL REGISTERS
3.1 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 S3C2450 restart on malfunction after its power on. At this time,
disable the interrupt generation and enable the Watchdog timer output for reset signal.
If controller restart is not desired and if the user wants to use the normal timer only, which is provided by the
Watchdog timer, enable the interrupt generation and disable the Watchdog timer output for reset signal.
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(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 timer output for reset signal.
1 = Assert reset signal of the S3C2450 at watchdog time-out
0 = Disable the reset function of the watchdog timer.
1
NOTE: Initial state of ‘Reset enable/disable’ is 1(reset enable). If user do not disable this bit, S3C2450 will be rebooted in
about 5.63sec (In the case of PCLK is 12MHz). So at boot loader, this bit should be disabled before under control of
Operating System, or Firmware.