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纯软件单片机串口
作者：佚名
纯软件单片机串口(一)
;Definition of variables
SEND_READ EQU 00H ;Bit for write(0) or read(1)
SEND_ENDS EQU 01H ;Bit for communiciating(1) or ends(0)
READ_ENDS EQU 02H ;Bit for reading(1) or ends(0)
BAUD_RAM_H EQU 30H ;Communite baud TH
BAUD_RAM_L EQU 31H ;Communite baud TL
AMEND_RAM_L EQU 32H
AMEND_RAM_H EQU 33H
SEND_CODE EQU 34H ;Byte that may be send
READ_CODE EQU 34H ;Read ends value byte
READ_BUFF EQU 35H ;Read bit RRC
SEND_COUNT EQU 36H ;Send bit count
READ_COUNT EQU 36H ;Read bit count
SEND_FLAG EQU 37H ;Send byte flag (0-->start send)
;Definition of constants
TXD EQU P1.6 ;TXD line
RXD EQU P3.2 ;RXD line
BAUD_H EQU 0FFH ;9600 4800 2400 1200 600 300
BAUD_L EQU 0A3H ;FFA0 FF40 FE80 FD00 FA00 F400
AMEND=03H
AMEND_H EQU 00H ;0000 0040 0080 0100 0200 0400
AMEND_L EQU 00H ; 20H 40H 80H 100H 200H 400H
ORG 0000H
SJMP MAIN
ORG 0003H
LJMP INPUT_INT
ORG 000BH
LJMP COMM_INT
ORG 0013H
LJMP READ_BYTE_INT
ORG 0040H
MAIN: MOV IE,#00H
MOV SP,#60H
MOV P1,#0FFH
MOV P3,#0FFH
MOV R1,#20H ;Clr CPU RAM
MOV R2,#40H
LOOP: MOV @R1,#00H
INC R1
DJNZ R2,LOOP
MOV BAUD_RAM_H,#BAUD_H
MOV BAUD_RAM_L,#BAUD_L
MOV AMEND_RAM_H,#AMEND_H
MOV AMEND_RAM_L,#AMEND_L
MOV TMOD,#01H
MOV TH0,BAUD_RAM_H
MOV TL0,BAUD_RAM_L
SETB ET0
SETB PT0
SETB EX0 ;Read int
SETB PX0
SETB IT0
SETB EX1
;SETB IT1
SETB EA
CLR SEND_READ
MOV SEND_FLAG,#0FFH
SETB TR0
LCALL SEND_TEST_CODE
LCALL SEND_LOOP
;LCALL READ_ONE
LCALL READ_STRING
LCALL ONLY_READ
;************************************
ONLY_READ: MOV R0,#40H
CLR SEND_READ
MOV SEND_FLAG,#0FH
READ_LOOP_1: MOV R7,#20H
MOV R0,#40H
READ_LOOP_0: SETB READ_ENDS
JB READ_ENDS,$
MOV @R0,READ_CODE
INC R0
MOV A,READ_CODE
CJNE A,#3FH,NEXT_0_0
LJMP SEND_EX
NEXT_0_0: DJNZ R7,READ_LOOP_0
LJMP READ_LOOP_1
SEND_EX: MOV R0,#40H
MOV R7,#20H
CLR SEND_READ
SEND_LOOP_0: MOV SEND_CODE,@R0
MOV SEND_FLAG,#00H
INC R0
SETB SEND_ENDS
JB SEND_ENDS,$
MOV A,SEND_FLAG
CJNE A,#03H,READ_LOOP_1
DJNZ R7,SEND_LOOP_0
LJMP READ_LOOP_1
RET
;************************************
SEND_LOOP: MOV SEND_CODE,#3DH
SEND_R: MOV SEND_FLAG,#00H
SETB SEND_ENDS
JB SEND_ENDS,$
MOV A,SEND_FLAG
CJNE A,#03H,N1
SJMP SEND_LOOP
N1: SETB READ_ENDS
JB READ_ENDS,$
MOV SEND_CODE,READ_CODE
SJMP SEND_R
RET
;************************************
READ_ONE: MOV SEND_FLAG,#0AH
RRR1: SETB READ_ENDS
JB READ_ENDS,$
MOV SEND_CODE,READ_CODE
MOV SEND_FLAG,#00H
SETB SEND_ENDS
JB SEND_ENDS,$
SJMP RRR1
RET
;***********************************
READ_STRING: CLR SEND_READ
READ: MOV SEND_FLAG,#0FH
MOV R1,#40H
MOV R2,#00H
READ_LOOP: SETB READ_ENDS
JB READ_ENDS,$
MOV @R1,READ_CODE
INC R1
INC R2
MOV A,READ_CODE
CJNE A,#3FH,NEXT1
SJMP SEND
NEXT1: CJNE R2,#20H,READ_LOOP
SEND: MOV R1,#40H
SEND_L: MOV SEND_FLAG,#00H
MOV SEND_CODE,@R1
SETB SEND_ENDS
JB SEND_ENDS,$
MOV A,SEND_FLAG
CJNE A,#03H,READ
INC R1
DJNZ R2,SEND_L
SJMP READ
RET
;******************************
SEND_TEST_CODE: MOV R6,#61H
MOV R7,#1AH
CLR SEND_READ
SEND_LOOP1: MOV SEND_CODE,R6
MOV SEND_FLAG,#00H
SETB SEND_ENDS
INC R6
JB SEND_ENDS,$
DJNZ R7,SEND_LOOP1
RET
;**********************************************************
READ_BYTE_INT: MOV @R1,READ_CODE
RETI
;*********************************************************************
;* SEND_READ EQU 01H Bit for send(0) or read(1) *
;* SEND_ENDS EQU 02H Bit for communiciating(1) or ends(0) *
;* READ_ENDS EQU 03H Bit for reading(1) or ends(0) *
;* SEND_COED EQU 31H Byte that may be send *
;* READ_CODE EQU 32H Read ends value byte *
;* SEND_COUNT EQU 33H Send bit count *
;* READ_COUNT EQU 33H Read bit count *
;* READ_BUFF EQU 34H Read bit circulate *
;* SEND_FLAG EQU 34H Send byte flag (0-->start send) *
;* *
;* BAUD_RAM_H EQU 35H Communite buad TH *
;* BAUD_RAM_L EQU 36H Communite buad TL *
;* AMEND_RAM_H EQU 37H Read interrupt amend value *
;* AMEND_RAM_L EQU 38H Read interrupt amend value *
;* TXD EQU P1.4 Data TXD line *
;* RXD EQU P1.3 Data RXD line *
;* When send: MOV SEND_CODE,Value_byte (Byte that will be send) *
;* MOV SEND_FLAG,#00H *
;* SETB SEND_ENDS *
;* if SEND_ENDS is 0 that shows completed send communiciation *
;* if SEND_FLAG isn't 03H that shows send communicating has *
;* beed interrupted by read_input,must jump to prosses *
;* read_input program. *
;* When read: SETB READ_ENDS *
;* SETB EX0 *
;* if READ_ENDS is 0 that shows completed read communiciation *
;* and return the value byte to READ_CODE. *
;* %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% *
;* % PROGRAM INITIALIZE % *
;* %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% *
;* Timer 0(or 1,2)must be worked with mode 1. *
;* INT_timer_0 and INT_exterior_0 be necessitated corwning priority. *
;* CPU Clock is 11.0592M *
;* Baud rate: 9600 4800 2400 1200 600 300 *
;* Timer value: FFA0H FF40H FE80H FD00H FA00H F400H *
;* Start bit amend: 0000H 0040H 0080H 0100H 0200H 0400H *
;* Timer value amend is 03H *
;* *
;* AUTHOR: Chen Muquan *
;* 1998.2.24 *
;* *
;*********************************************************************
COMM_INT: PUSH ACC
PUSH PSW
MOV A,TL0 ;================
ADD A,BAUD_RAM_L
MOV TL0,A ;================
MOV TH0,BAUD_RAM_H ;================
JB SEND_READ,READ_DATA ;0 Send or 1 Read
;******** Send communicating **********
MOV A,SEND_FLAG ;Process send flag
CJNE A,#00H,COMM_NEXT1 ;Send start bit
CLR TXD ;One start_bit low
INC SEND_FLAG
MOV SEND_COUNT,#08H
POP PSW
POP ACC
RETI
COMM_NEXT1: CJNE A,#01H,COMM_NEXT2 ;Send circulation
MOV A,SEND_CODE
RRC A
MOV TXD,C
MOV SEND_CODE,A
DJNZ SEND_COUNT,COMM_EXIT ;circulation end
INC SEND_FLAG
POP PSW
POP ACC
RETI
COMM_NEXT2: CJNE A,#02H,COMM_EXIT ;Send stop bit
SETB TXD ;One stop_bit high
INC SEND_FLAG
CLR SEND_ENDS ;completed send
communication
COMM_EXIT: POP PSW
POP ACC
RETI
;********* Read communicating **********
READ_DATA: MOV A,READ_BUFF
MOV C,RXD
RRC A
MOV READ_BUFF,A
DJNZ READ_COUNT,READ_EXIT ;Completed read
MOV READ_CODE,A ;Write read data byte
CLR READ_ENDS ;Completed read
communicate
CLR IE0 ;Setup for read next byte
SETB EX0 ;Enable read interrupt
CLR SEND_READ ;Setup send status
SETB IE1
READ_EXIT: POP PSW
POP ACC
RETI
;*******************************************************************
;* The following subroutine is a exterior interrupt serve on *
;* communiciated interrupt *
;*******************************************************************
INPUT_INT: PUSH ACC
PUSH PSW
CLR EX0 ;=======================
CLR SEND_ENDS ;Interrup send commiciating
MOV SEND_FLAG,#0AH ;Alter the send_flag for main
program
SETB TXD
CLR TR0 ;Setup for read
SETB SEND_READ ;Set INI_timer status for read
MOV READ_COUNT,#08H
MOV A,BAUD_RAM_L ;Amend start bit clock cycle
SUBB A,AMEND_RAM_L
MOV TL0,A
MOV A,BAUD_RAM_H
SUBB A,AMEND_RAM_H
MOV TH0,A
SETB TR0
CLR TF0
POP PSW
POP ACC
RETI
END
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