DSM 96M4371o, Руководство пользователя

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System Installation
96M4371o
User’s Manual
3-4
The related Control Registers of WDT are all included in the following sample
program that is written in Assembly language. User can fill a non-zero value into the
Time-out Value Register to enable/refresh WDT. System will be reset after the
Time-out Value to be counted down to zero. Or user can directly fill a zero value into
Time-out Value Register to disable WDT immediately. To ensure a successful
accessing to the content of desired Control Register, the sequence of following
program codes should be step-by-step run again when each register is accessed.
Additionally, there are maximum 2 seconds of counting tolerance that should be
considered into user’ application program. For more information about WDT, please
refer to ITE8721 data sheet.
There are two PNP I/O port addresses that can be used to configure WDT,
1) 0x2E:Test 1 Register
2) 0x2F:Test 2 Register
Below are some example codes, which demonstrate the use of WDT.
.model small
.386p
.stack
.data
ADDRESS dw 0FFFFh
.code
pgm:
mov
ADDRESS,002eh ; I suppose 2Eh that is the address of SIO
mov dx, ADDRESS ; enter MB PnP mode in 2Eh
mov al, 87h
out
dx, al
mov al, 01h
out dx, al
mov al, 55h
out dx, al
mov al, 55h
out dx, al
mov al, 20h ; read the Chip ID to check the address of SIO
out dx, al
inc dx
in al, dx
; default =87h
mov bl, al
mov al, 21h
mov dx, ADDRESS
out dx, al
inc dx