Design of communication function realized by PIC microcontroller

1. PIC1 microcontroller programming (sending part)

LIST P=16F877

#INCLUDE P16F876.INC

CBLOCK 0X24; Reserve three bytes for display

COUNT; used as a counter or register

ENDC

ORG 0X0000 ; program reset entry

NOP

START GOTO MAIN

ORG 0X20

MAIN MOVLW 0X30; The following will initialize the RAM content

MOVWF FSR; Start from unit 30H

MOVLW 0X30 ; assign value 30H to unit 30H

MOVWF COUNT

INTRAM MOVF COUNT, 0; assign 30H to 7FH to unit 30H to 7FH

MOVWF INDF

INCF COUNT, 1

INCF FSR, 1

BTFSS COUNT, 7

GOTO INTRAM

BSF STATUS, RP0; Initialize the SCI component

MOVLW 0X19; Set the transmission baud rate to about 9600 bps

MOVWF SPBRG

MOVLW 0X04; Select asynchronous high-speed mode to transmit 8-bit data

MOVWF TXSTA

BCF STATUS, RP0

MOVLW 0X80; Enable synchronous serial port to work

MOVWF RCSTA

BSF STATUS, RP0

BSF T RISC , 7; Set RC6 and RC7 to input mode and disconnect the external circuit

BSF TRISC, 6

BCF STATUS, RP0

MOVLW 0X30; 30H is sent as a synchronization character

MOVWF FSR

MOVF INDF,0

MOVWF TXREG; write the data to be sent into the transmit buffer TXREG

BSF STATUS, RP0

BSF TXSTA, TXEN; Send permission

BCF STATUS, RP0

BSF RCSTA, CREN; receive data enable

LOOPTX BTFSS PIR1, RCIF ; Wait for the response byte from PIC2

GOTO LOOPTX

MOVF RCREG, 0; read response byte, clear RCIF

LOOPTX1 BTFSS PIR1, TXIF; send next byte

GOTO LOOPTX1

INCF FSR

MOVF INDF,0

MOVWF TXREG

BTFSS FSR, 7; Have the contents of the 30H~7FH units been sent?

GOTO LOOPTX ; No, continue to send the next byte

BSF STATUS, RP0; if yes, stop sending

BCF TXSTA, TXEN

BCF STATUS, RP0; Data transmission completed

CALLLED; call the display subroutine to display the sent data

END; program ends

2. PIC2 microcontroller programming (receiving part)

LIST P=16F876

#INCLUDE P16F876.INC

CBLOCK 0X24

COUNT

ENDC

ORG 0X0000

NOP

START GOTO MAIN

MAIN BSF STATUS, RP0; Initialization procedure is the same as the sending subroutine

MOVLW 0X19; baud rate setting is the same as PIC1

MOVWF SPBRG

MOVLW 0X04 ; asynchronous high-speed transmission

MOVWF TXSTA

BCF STATUS, RP0

MOVLW 0X80; serial port operation enable

MOVWF RCSTA

BSF STATUS, RP0

BSF TRISC, 7; isolated from external circuits

BSF TRISC, 6

BCF STATUS, RP0

MOVLW 0X30; store the sent data starting from unit 30H

MOVWF FSR

BSF RCSTA, CREN; receive enable

BSF STATUS, RP0

BSF TXSTA, TXEN; Send permission

BCF STATUS, RP0

WAIT BTFSS PIR1, RCIF; Waiting to receive data

GOTO WAIT

MOVF RCREG, 0; read data

MOVWF INDF ；Store the received response byte into the RAM of PIC2

INCF FSR

MOVWF TXREG ; send response byte

LOOPTX BTFSS PIR1, TXIF; Wait for writing to complete

GOTO LOOPTX

BTFSS FSR, 7; Are all data received?

GOTO WAIT1; No, continue to receive other data

BCF RCSTA, RCEN; After receiving, turn off the receiving and sending data enable

BSF STATUS, RP0

BCF PIE1, TXEN

BCF STATUS, RP0

CALL LED; call the display subroutine to display the received data

END; program ends