NuDAQ PET-48DIO, Руководство пользователя, Страница: 31 / 38

Control Programming
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25
To initial 8253
MOV DX , INDEX ; DATA OF INDEX SAME AS I/O
; ADDRESS THAT SET BY SW1
MOV AL , CTRL53 ; CTRL53 = 83H
OUT DX , AL ; SET INDEX TO 8253 CONTROL
; WORD
JMP $+2 ; DELAY
INC DX ; POINT TO DATA READ/WRIT
; ADDRESS
MOV AL , CW0 ; CW0 = 00110000B
OUT DX , AL ; 8253 COUNT 0 AS MODE 0:
; INTERRUPT ON TERMINAL
; COUNT
JMP $+2 ; DELAY
MOV AL , CW1 ; CW1 = 01110100B
OUT DX , AL ; 8253 COUNT 1 AS MODE 2:
; RATE GENERATOR
JMP $+2 ; DELAY
MOV AL , CW2 ; CW2 = 10110000B
OUT DX , AL ; 8253 COUNT 2 AS MODE 0:
; INTERRUPT ON TERMINAL
; COUNT
JMP $+2 ; DELAY
To set event counter
MOV DX , INDEX ; DATA OF INDEX SAME AS I/O
; ADDRESS THAT SET BY SW1
MOV AL , C530 ; C530 = 80H
OUT DX , AL ; INDEX TO COUNT 0
JMP $+2 ; DELAY
INC DX ; POINT TO DATA READ/WRITE
; ADDRESS
MOV AL , 32H ; LOAD LEAST BYTE 32H
OUT DX , AL ; LOAD LEAST BYTE
JMP $+2 ; DELAY
MOV AL , 00H ; LOAD MOST BYTE 00H
OUT DX , AL ; LOAD MOST BYTE
JMP $+2