User manual
TPC-1261H User Manual 50
Table B.1: Watchdog Timer Registers
Address of 
register (2E)
Attribute Description
Read/Write Value (2F)
 and
description
87 (hex) ----- Write this address to I/O address
port 2E (hex) twice to unlock the 
W83627HF
07 (hex) write Write 08 (hex) to select register of 
watchdog timer.
30 (hex) write Write 01 (hex) to enable the function 
of the watchdog timer. Disabled is 
set as default.
F5 (hex) write Set seconds or minutes as units for 
the timer.
Write 0 to bit 3: set second as counting unit. [default]
Write 1 to bit 3: set minute as counting unit
F6 (hex) write 0: stop timer [default]01~FF (hex): 
The amount of the count, in seconds 
or minutes, depends on the value 
set in register F5 (hex). This number 
decides how long the watchdog 
timer waits for strobe before gener-
ating an interrupt or reset signal. 
Writing a new value to this register 
can reset the timer to count with the 
new value.
F7 (hex) rd/wr Bit 6: Write 1 to enable keyboard to 
reset the timer, 0 to disable.[default] 
Bit 5: Write 1 to generate a timeout 
signal immediately and automati-
cally return to 0. [default=0] Bit 4: 
Read status of watchdog timer, 1 
means timer is "time out".
AA (hex) ----- Write this address to I/O port 2E 
(hex) to lock the watchdog timer.2 










