8253.txt

编程将8253计数器0

TIM_CTL EQU       22bH
TIMER0  EQU       228H
TIMER1  EQU       229H
TIMER2  EQU       22aH
MODE03  EQU       00110110B
MODE13  EQU       01110100B
MODE22  EQU       10110100B  
DATA    SEGMENT
DATA    ENDS
CODE    SEGMENT
ASSUME  CS:CODE,DS:DATA
START:  PUSH      DS
	MOV     AX,0
	PUSH    AX
	MOV     AX,DATA
	MOV     DS,AX
	CLI                       ;关中断
	MOV     DX,TIM_CTL        ;定时器0工作在方式3
	MOV     AL,MODE03
	OUT     DX,AL
	MOV     DX,TIMER0
	MOV     AL,00H
	OUT     DX,AL
	mov     al,01h
	out     dx,al
	MOV     DX,TIM_CTL       ;定时器1工作在方式3
	MOV     AL,MODE13
	OUT     DX,AL
	MOV     DX,TIMER1
	MOV     AL,18H
	OUT     DX,AL
	mov     al,00h
	out     dx,al
	MOV     DX,TIM_CTL      ;定时器2工作在方式2
	MOV     AL,MODE22
	OUT     DX,AL
	MOV     DX,TIMER2
	MOV     AL,0aH
	OUT     DX,AL
	mov     al,00h
	out     dx,al
	STI
	JMP $
	CODE    ENDS
END     START