User manual

PCE-5124 User Manual 94
Table A.1: Watchdog timer registers
Address of
register (2E)
Attribute
Read/
Write
Value (2F)& description
87 (hex) ----- Write this address to I/O address port 2E
(hex) twice to unlock the W83627HG
07 (hex) write Write 08 (hex) to select register of watch-
dog 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 count-
ing unit. [default]. Write 1 to bit 3: set min-
utes 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 generating an interrupt or
reset signal. Writing a new value to this
register can reset the timer to count with
the new value.
F7 (hex) read/
write
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 automatically return to 0.
[default=0]
Bit 4: Read status of watchdog timer, 1
means timer is “timeout”.
AA (hex) ----- Write this address to I/O port 2E (hex) to
lock the watchdog timer 2.