sy4-2.asm

来自「硬件电路测试参考数据包」· 汇编 代码 · 共 49 行

;       实验四  8253定时/计数器实验     SY4-2.ASM

TIM_CTL EQU     293H
TIMER0  EQU     290H
TIMER1  EQU     291H
TIMER2  EQU     292H
MODE03  EQU     00110110B
MODE13  EQU     01110110B

DATA    SEGMENT
MESS    DB      '8253A TIMER0 IN MODE3! COUNT=15C4H',0DH,0AH
	DB      '8253A TIMER1 IN MODE3! COUNT=03E8H',0DH,0AH,'$'
DATA    ENDS

CODE    SEGMENT
MAIN    PROC    FAR
ASSUME  CS:CODE,DS:DATA
START:  PUSH DS
	MOV     AX,0
	PUSH    AX
	NOP
	MOV     AX,DATA
	MOV     DS,AX
	CLI
	MOV     DX,TIM_CTL
	MOV     AL,MODE03
	OUT     DX,AL
	MOV     DX,TIMER0
	MOV     AL,0C4H
	OUT     DX,AL
	MOV     AL,15H
	OUT     DX,AL
	MOV     DX,TIM_CTL
	MOV     AL,MODE13
	OUT     DX,AL
	MOV     DX,TIMER1
	MOV     AL,0E8H
	OUT     DX,AL
	MOV     AL,04H
	OUT     DX,AL
	STI
	MOV     DX,OFFSET MESS
	MOV     AH,09
	INT     21H
	RET
MAIN    ENDP
CODE    ENDS
	END     START