Advantech ASMB-975 Series, Руководство пользователя

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ASMB-975 User Manual 102
The ASMB-925 Series watchdog timer can be used to monitor system software oper-
ation and take corrective action if the software fails to function within the programmed
period. This section describes the operation of the watchdog timer and how to pro-
gram it.
A.1 Watchdog Timer Overview
The watchdog timer is built in to the EC controller IT8528E. It provides the following
functions for user programming:
 Can be enabled and disabled by user program
 Timer can be set from 1 to 255 seconds
 Generates an interrupt or resets signal if the software fails to reset the timer
before time-out
A.2 Programming the Watchdog Timer
The I/O port address of the watchdog timer is as below:
Here is an example to step by step program the Watchdog Timer.
Address Description
0x57 Event - Warm Reset: 0x04
0x5E Warm Reset Timer (High BYTE)
Based 100ms
0x5F Warm Reset Timer (Low BYTE)
Step Action Description
00 Read 0x299 port Clear I/O port
Wait IBF clear 0x29A, BIT1, = 0
01 Write 0x89 to 0x29A
Wait IBF clear 0x29A, BIT1, = 0
02 Write 0x5E to 0x299 port
Wait IBF clear 0x29A, BIT1, = 0
03 Write 0x00 to 0x299 port Set 10 sec (high byte)
Wait IBF clear 0x29A, BIT1, = 0
04 Write 0x89 to 0x29A
Wait IBF clear 0x29A, BIT1, = 0
05 Write 0x5F to 0x299 port
Wait IBF clear 0x29A, BIT1, = 0
06 Write 0x64 to 0x299 port Set 10 sec (low byte)
Wait IBF clear 0x29A, BIT1, = 0
07 Write 0x89 to 0x29A
Wait IBF clear 0x29A, BIT1, = 0