【西南交大swjtu微机与接口技术实验】D/A变换实验实验三：波形发生器

做一个存档。实验要求与电路连接见参考指导书。

1、主程序产生锯齿波

2、按下KK1+输出五个周期的三角波，继续输出被中断的锯齿波

3、按下KK2+输出五个周期的方波，继续输出被中断的锯齿波

程序代码

IOY0 EQU 0600H
DA EQU IOT0+00H*2

SSTACK SEGMENT STACK
	DW 32 DUP(?)
SSTACK ENDS

CODE SEGMENT
	ASSUME CS:CODE
START:	PUSH DS
	MOV AX,0000H
	MOV DS,AX

	MOV AX,OFFSET MIR7
	MOV SI,003CH
	MOV [SI],AX
	MOV AX,CS
	MOV SI,003EH
	MOV [SI],AX
	
	MOV AX,OFFSET MIR6
	MOV SI,0038H
	MOV [SI],AX
	MOV AX,CS
	MOV SI,003AH
	MOV [SI],AX
	CLI
	POP DS

	;初始化主片8259
	MOV AL,11H
	OUT 20H,AL
	MOV AL,08H
	OUT 21H,AL
	MOV AL,04H
	OUT 21H,AL
	MOV AL,01H
	OUT 21H,AL
	MOV AL,2FH
	OUT 21H,AL

	STI
	MOV AX,00H
	MOV DX,DA
	MOV AL,00H
A0:	OUT DX,AL
	CALL DELAY
	INC AL
	JMP A0

MIR6:   PUSH AX
	PUSH CX
	STI
	CALL DELAY
	MOV CX,5
A1:	MOV AL,00H
LOOP1:	OUT DX,AL
	CALL DELAY
	INC AL
	CMP AL,0FFH
	JB LOOP1

	MOV AL,0FFH
	MOV DX,DA
LOOP2:	OUT DX,AL
	CALL DELAY
	DEC AL
	CMP AL,0
	JA LOOP2
	LOOP A1

	POP CX
	POP AX
	MOV AL,20H
	MOV 20H,AL
	IRET

MIR7:	PUSH AX
  	PUSH CX
	STI
	CALL DELAY
	MOV CX,5
A2:	MOV AL,00H
	OUT DX,DA
	CALL DELAY1
	MOV AL,7FH
	OUT DX,AL
	CALL DELAY1
	LOOP A2
	POP CX
	POP AX
	MOV AL,20H
	MOV 20H,AL
	IRET

DELAY:	PUSH CX
	MOV CX,03FFH
AA0:	PUSH AX
	POP AX
	LOOP AA0
	POP CX
	RET

DELAY1： PUSH CX
	MOV CX,0FF00H
AA1:	PUSH AX
	POP AX
	LOOP AA1
	POP CX
	RET

CODE 	ENDS
	END START