8250.asm

单片机MSC51设计的5个源程序：1、数据排序2、多功能数字钟设计3、P1口循环亮灯设计4、脉冲计数器5、8250芯片串口扩展。另附程序详细介绍。

	ORG 39A0H		;RCV DATA IN 4000h..... :10h,11h,12h
	PDATA	EQU	8000H	;BTS-LSB
	MSB	EQU	8001H
	LINE	EQU 	8003H
	LSTAT	EQU	8005H	
START:	MOV SP,#50H
	MOV A,#80H		;DLAB=1
	MOV DPTR,#LINE
	MOVX @DPTR,A
	MOV A,#18H		;BTS=4800
	MOV DPTR,#8000H
	MOVX @DPTR,A
	MOV DPTR,#MSB
	MOV A,#00H
	MOVX @DPTR,A
	MOV A,#03H		;8-BIT,1-STOP
	MOV DPTR,#LINE
	MOVX @DPTR,A
	MOV A,#00H		;NO-INT
	MOV DPTR,#8001H
	MOVX @DPTR,A
	MOV B,#10H
	MOV DPTR,#4000h		
MAIN:	PUSH DPH
	PUSH DPL
	CALL SEND
	CALL RCV
	POP DPL
	POP DPH
	MOVX @DPTR,A
	INC DPTR
	INC B
	MOV A,B
	CJNE A,#00H,MAIN
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
GOOD:	MOV R4,#0A0H
	CALL BUF1
GOOD1:	CALL DIS
	DJNZ R4,GOOD1
	CALL BUF2
GOOD2:	CALL DIS		
	SJMP GOOD2
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
ERR:	CALL BUF3
ERR1:	CALL DIS
	SJMP ERR1		
BUF1:	MOV 7EH,#08H
	MOV 7DH,#02H
	MOV 7CH,#05H
	MOV 7BH,#00H
	MOV 7AH,#14H
	MOV 79H,#14H
	RET
BUF2:	MOV 7EH,#09H
	MOV 7DH,#00H
	MOV 7CH,#00H
	MOV 7BH,#0DH
	MOV 7AH,#10H
	MOV 79H,#10H
	RET
BUF3:	MOV 7EH,#08H
	MOV 7DH,#02H
	MOV 7CH,#05H
	MOV 7BH,#00H
	MOV 7AH,#0EH
	MOV 79H,#15H
	RET

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
SEND:	MOV DPTR,#LSTAT
WAIT1:	MOVX A,@DPTR
	ANL A,#20H
	JZ WAIT1 
	MOV A,B
	MOV DPTR,#PDATA
	MOVX @DPTR,A
	RET	
;------------------------------------------------------
RCV:	MOV DPTR,#LSTAT
WAIT2:	MOVX A,@DPTR
	JNB ACC.0,WAIT2
	ANL A,#0EH
	JNZ ERR
	MOV DPTR,#PDATA
	MOVX A,@DPTR
	RET
;---------------------------------------------------------
DIS:	MOV A,#00H
	MOV R0,#21H
	MOVX @R0,A
	MOV R0,#7EH
	MOV R2,#20H
	MOV R3,#00H
	MOV DPTR,#LS0
LS2:	MOV A,@R0
	MOVC A,@A+DPTR
	MOV R1,#22H
	MOVX @R1,A
	MOV A,R2
	DEC R1
	MOVX @R1,A
	DEC R0
LS1:	DJNZ R3,LS1
	CLR C
	RRC A
	MOV R2,A
	JNZ LS2
	INC R1
	MOV A,#0FFH
	MOVX @R1,A
	RET
LS0:         DB 0C0H,0F9H,0A4H,0B0H,99H,92H,82H,0F8H,80H,90H
	DB 88H,83H,0C6H,0A1H,86H,8EH,0FFH,0CH,89H,7FH,0BFH,8FH
END