在两个单片机之间建立串口通信。

说明：我们使用数码管显示接收到的数据，数据是对方的按键编号。

硬件连接图：

有一点至关重要，就是两个单片机要共地。发送和接收引脚在两个单片机上交叉相连。

这里采用的是异步发送和接收。

发送原理图：

EUSART接收图：

时序图：

实现代码流程图：

实现代码：

#include

__CONFIG _CONFIG1, _LVP_OFF & _FCMEN_ON & _IESO_OFF & _BOR_OFF & _CPD_OFF & _CP_OFF & _MCLRE_ON & _PWRTE_ON & _WDT_OFF & _INTRC_OSC_NOCLKOUT

__CONFIG _CONFIG2, _WRT_OFF & _BOR21V

udata_shr

counter res 1

counter1 res 1 ;扫描按键变量

counter2 res 1 ;延时程序微调参数

key_state res 1 ;按键状态

keynum res 1 ;按键标号

swap res 1 ;确认按键转换值

keypress res 1

keypressbak res 1

keyrelease res 1

LED1 res 1

LED2 res 1

LED3 res 1

LED4 res 1

UDATA

counter3 res 1

counter4 res 1

sign res 1

reset code 0x0000

pagesel start

goto start

;int_vector code 0x0004

code

start

banksel ANSEL ;设置PORTA为数字模式

clrf ANSEL

banksel ANSELH ;设置PORTB为数字模式

clrf ANSELH

banksel TRISB ;设置PORTB为输入模式

movlw b'11111111'

movwf TRISB

banksel WPUB ;设置PORTB弱上拉

movlw b'11111111'

movwf WPUB

banksel OPTION_REG

movlw b'01000101' ;TMR0 64分频

movwf OPTION_REG

banksel T1CON

movlw b'10010001' ;打开TMR1，设置1:8预分频，内部时钟源1:4分频

movwf T1CON

banksel TRISA ;设置PORTA<3:0>为输出，接数码管的共阴极

movlw b'11100000'

movwf TRISA

banksel PORTA

clrf PORTA

banksel TRISC

movlw b'00000000' ;设置PORTC为输出，接8段数码管

movwf TRISC

clrf counter1

;***************************************

;串口发送配置

banksel TXSTA

movlw b'10100100'

movwf TXSTA

banksel BAUDCTL

movlw b'00000001'

movwf BAUDCTL

banksel SPBRG ;设置波特率

movlw d'25'

movwf SPBRG

banksel RCSTA

movlw b'10010000'

movwf RCSTA

;***************************************

loop

movlw HIGH Table1

movwf PCLATH

movf counter1,0

call Table1

banksel TRISB

movwf TRISB

movf counter1,0

call Table1

banksel PORTB

movwf PORTB

movf PORTB,0

movwf key_state

movlw b'11001000'

iorwf key_state,1

movf counter1,0

call Table1

xorwf key_state,0

movwf swap

comf swap,1

incfsz swap,1

goto case1

incf counter1,1

movf counter1,0

call Table1

banksel TRISB

movwf TRISB

movf counter1,0

call Table1

banksel PORTB

movwf PORTB

movf PORTB,0 ;读取I/O状态

movwf key_state

movlw b'11001000'

iorwf key_state,1

movf counter1,0

call Table1

xorwf key_state,0

movwf swap

comf swap,1

incfsz swap,1

goto case2

incf counter1,1

movf counter1,0

call Table1

banksel TRISB

movwf TRISB

movf counter1,0

call Table1

banksel PORTB

movwf PORTB

movf PORTB,0 ;读取I/O状态

movwf key_state

movlw b'11001000'

iorwf key_state,1

movf counter1,0

call Table1

xorwf key_state,0

movwf swap

comf swap,1

incfsz swap,1

goto case3

incf counter1,1

movf counter1,0

call Table1

banksel TRISB

movwf TRISB

movf counter1,0

call Table1

banksel PORTB

movwf PORTB

movf PORTB,0 ;读取I/O状态

movwf key_state

movlw b'11001000'

iorwf key_state,1

movf counter1,0

call Table1

xorwf key_state,0

movwf swap

comf swap,1

incfsz swap,1

goto case4

goto continue

case1

btfsc key_state,4

goto key2

movlw d'1'

movwf keynum

call DealKeyPress

goto continue

key2

btfsc key_state,2

goto key3

movlw d'2'

movwf keynum

call DealKeyPress

goto continue

key3

btfsc key_state,1

goto key4

movlw d'3'

movwf keynum

call DealKeyPress

goto continue

key4

btfsc key_state,0

goto continue

movlw d'4'

movwf keynum

call DealKeyPress

goto continue

case2

;-------------------------------------------------

;下面代码实现K10K8K5的按键处理

btfsc key_state,2

goto key8

movlw d'10'

movwf keynum

call DealKeyPress

goto continue

;------------------------------------

;处理K8

key8

btfsc key_state,1

goto key5

movlw d'8'

movwf keynum

call DealKeyPress

goto continue

;------------------------------------

;处理K5

key5

btfsc key_state,0

goto case3

movlw d'5'

movwf keynum

call DealKeyPress

goto continue

case3

;----------------------------------

;处理K6/K9

btfsc key_state,1

goto key6

movlw d'9'

movwf keynum

call DealKeyPress

goto continue

key6

btfsc key_state,0

goto case4

movlw d'6'

movwf keynum

call DealKeyPress

goto continue

case4

;-----------------------------------------

;处理K7

btfsc key_state,0

goto continue

movlw d'7'

movwf keynum

call DealKeyPress

continue

banksel PIR1

btfss PIR1,RCIF ;检测有无收到数据

goto lOOP2

call receive

lOOP2

call display

clrf counter1

goto loop

;-----------------------------------

;按键去抖，约8mS

delay

movlw d'4'

movwf counter2

LOOP2

banksel TMR0

clrf TMR0

LOOP1

banksel INTCON

btfss INTCON,T0IF

goto LOOP1

bcf INTCON,T0IF

decfsz counter2,1

goto LOOP2

return

delay2

incfsz counter3,1

goto delay2

return

;--------------------------------

;按键处理程序

;

DealKeyPress

clrf LED1

clrf LED2

clrf LED3

; clrf LED4

call delay

banksel TMR1H

clrf TMR1H

banksel TMR1L

clrf TMR1L

clrf keypress

presstime

banksel PIR1

btfss PIR1,TMR1IF

goto next

bcf PIR1,TMR1IF

incf keypress

movlw d'2'

subwf keypress,0

banksel STATUS

btfsc STATUS,C

goto longpress

next

movf counter1,0

call Table1

banksel TRISB

movwf TRISB

banksel PORTB

movwf PORTB

movf PORTB,0 ;读取I/O状态

movwf key_state

movlw b'11001000'

iorwf key_state,1

movf counter1,0

call Table1

xorwf key_state,0

movwf swap

comf swap,1

incfsz swap,1

goto presstime

call delay

banksel TMR1H

clrf TMR1H

banksel TMR1L

clrf TMR1L

clrf keyrelease

releasetime

banksel PIR1

btfss PIR1,TMR1IF

goto next1

bcf PIR1,TMR1IF

incf keyrelease

movlw d'1'

subwf keyrelease,0

banksel STATUS

btfsc STATUS,C

goto click

next1

movf counter1,0

call Table1

banksel TRISB

movwf TRISB

banksel PORTB

movwf PORTB

movf PORTB,0 ;读取I/O状态

movwf key_state

movlw b'11001000'

iorwf key_state,1

movf counter1,0

call Table1

xorwf key_state,0

movwf swap

comf swap,1

incfsz swap,1

goto over

goto releasetime

over

call delay

banksel TMR1H

clrf TMR1H

banksel TMR1L

clrf TMR1L

clrf keypress

presstime1

banksel PIR1

btfss PIR1,TMR1IF

goto next2

bcf PIR1,TMR1IF

incf keypress

movlw d'1'

subwf keypress,0

banksel STATUS

btfsc STATUS,C

goto click

next2

movf counter1,0

call Table1

banksel TRISB

movwf TRISB

banksel PORTB

movwf PORTB

movf PORTB,0 ;读取I/O状态

movwf key_state

movlw b'11001000'

iorwf key_state,1

movf counter1,0

call Table1

xorwf key_state,0

movwf swap

comf swap,1

incfsz swap,1

goto presstime1

movf keynum,0

movwf LED1

goto back

longpress ;长按计数清零

goto back

click

movf keynum,0

movwf LED1

back

;*********************************

;发送按键编号

banksel PIR1

lOOP

btfss PIR1,TXIF

goto lOOP

movf LED1,0

banksel TXREG

movwf TXREG

banksel TXSTA

lOOP1

btfss TXSTA,TRMT

goto lOOP1

;*********************************

return

;--------------------------------

;显示数码管

;

display

banksel PORTA

movlw b'11111110'

movwf PORTA

movf LED1,0

call Table3

banksel PORTC

movwf PORTC

movwf counter

btfss counter,6

goto lOOP5

banksel PORTA

bsf PORTA,4

goto next4

lOOP5

banksel PORTA

bcf PORTA,4

next4

call delay2

banksel PORTA

movlw b'11110111'

movwf PORTA

movf LED4,0

call Table3

banksel PORTC

movwf PORTC

movwf counter

btfss counter,6

goto lOOP6

banksel PORTA