mt8880.asm

8880拨号程序,用于拨出200电话 可修改后进行其他拨号

/*例：把自通信线路发来的限定位数的号码接收，存储，以双音群模式*/
/*转发至通信线路*/

 
	ORG 0000H
	LJMP MAIN
	ORG 03H
	PUSH ACC
	PUSH DPH
	PUSH DPL
	MOV DPTR,#6800H	;6800H=0110100000000000B 
					;R/~W=A11=1，RSI=A12=0,READ FROM RDR
	MOVX A,@DPTR
	LCALL DELAY
	MOV DPTR,#6000H;	R/~W=A11=0,RSI=A12=0,WRITE TO TDR
	MOVX @DPTR,A
	POP DPL
	POP DPH
	POP ACC
	RETI
	
MAIN:
	SETB IT0
	SETB EA
	SETB EX0
	MOV DPTR,#7000H	;WRITR CR
	CLR A
	MOVX @DPTR,A	;WRITE CRA
	MOV A,#08H
	MOVX @DPTR,A	;WRITE CRA,SET B3=1
	MOV A,#02H
	MOVX @DPTR,A	;WRITE CRB
	MOV A,#0DH
	MOVX @DPTR,A	;WRITE CRA
	MOV SP,#60H
LOOP:
	NOP
	SJMP LOOP
DELAY:
	MOV R3,#0FFH
DE1:
	MOV R4,#0FFH
DE2:
	DJNZ R4,DE2
	DJNZ R3,DE1
	RET
	END