Installation and Configuration
OI: IPC370T
Page 16 of 38
Rev. 1.00 dated 1.7.2004
2.4
Watchdog
In the BIOS set-up the following setting options are intended for the watchdog.
Address:
Three I/O addresses are offered for selection
over which the application software can access to the watchdog.
Timeout:
Can be set from 400 milliseconds until 600 seconds.
Within the set time, the watchdog must be triggered by the application,
otherwise a RESET is caused.
Delay:
Can be set from 1 until 1800 seconds.
The set time is bided after the start of the watchdog for one time,
until the timeout counter begins to count.
The application software can access to the watchdog register via the set I/O address
with IN and OUT commands.
ISA bus
Designation
Description
Bit 0
RUN (R/W)
1 = Timeout counter counting.
Change 0 on 1 resets TIMEOUT (Bit2) and initializes all counters.
Bit 1
TRIGGER (R/W)
must be toggled within the set time period
in order to reset the timeout counter.
Bit 2
TIMEOUT (R)
0 = no timeout. Default after Power-Up or after setting Bit0.
1 = Timeout is occurred. Reset was caused.
With timeout the watchdog is stopped.
Furthermore the watchdog can be addressed via the I
2
C bus.
In this case timeout and delay counters can be loaded by the application software.
Starting and triggering of the watchdog is only possible by the manner as described above.
Watchdog I
2
C interface: Device address = B0h/B1h
The watchdog consists of individual byte registers.
Write:
Device address B0h, register address, data byte
Read :
not possible
For writing the watchdog must not have been started (Bit 0 via I/O = 0)
Address
Data Byte
Reset Condition Read/Write
Bit
Remark
0
TimeOut Low Byte
100d
W
Byte
1
TimeOut High Byte
0
W
Byte
2
Delay Low Byte
100d
W
Byte
3
Delay High Byte
0
W
Byte
Settings in the VIA Southbridge 82C686: Device 7 Function 0: Rx76[1] = 1 Rx8B[0] = 1
Rx[79] and Rx[78] contains the I/O addresses
e.g.:
Rx[79] = 03
Rx[78] = 00 corresponds to address 300H
Summary of Contents for IPC370T
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