i2csint.p16.ex.txt

Microchip PIC18F 设备驱动代码 I2C部分

;###############################################################################;
;# TITLE   "I2C Master General Purpose Library Checking Software"               ;
;#                                                                              ;
;#                                                                              ;
;#      Program:        I2CSInt.ex.txt                                          ;
;#      Version:        1.0                                                     ;
;#      Revision Date:                                                          ;
;#      Author:         Vidyadhar                                               ; 
;#                                                                              ;
;#                                                                              ;
;# Program demonstrates use of I2C Slave general purpose library module.        ;
;# This program transmits 4 bytes of Data on read command from Master           ;
;# This program receives 4 bytes of Data on write command from Master           ;
;# Timer0 is used for error recovery purpose. It is initialized to interrupt    ;
;# every 1 ms. The system clock is taken as 4 MHz.                              ;
;###############################################################################;
                                                ;
      list p=16f877                             ;
        #include <P16F877.INC>                  ;
                                                ;
;***********************************************;      
        #include "I2CSInt.inc"                  ;This include all required files and variables.            
;***********************************************;

        UDATA_SHR

DupW    res     1
DupStat res     1

;***********************************************;
                                                ;
Starthere   code    0x0000                      ;
                                                ;
        goto    Start                           ;
;-----------------------------------------------;
                                                ;
intr        code    0x0004                      ;
                                                ;
        goto    ISRHandler                      ;
                                                ;
;-----------------------------------------------;
Strt        code                                ;
                                                ;
Start:                                          ;
                                                ;
      ;                                         ;
      ;                                         ;
      ;                                         ;
                                                ;
        BANKSEL TRISC                           ;
        bsf     TRISC,4                         ;SDA is made i/p
        bsf     TRISC,3                         ;SCL is made i/p
                                                ;
        bcf     OPTION_REG,T0CS                 ;Timer0 with system clock
        movlw   001h                            ;Prescaler 4 (Timer0 timeout = ~1 ms at 4 MHz)
        iorwf   OPTION_REG,f                    ;
                                                ;
        PAGESEL I2CSIntInit                     ;
        call    I2CSIntInit                     ;to Initialise SSP MOdule
                                                ;
; To Send 4 bytes Data1, Data2, Data3, Data4    ;
; to the Master                                 ;
                                                ;
        ;                                       ;
        ;                                       ;
        ;                                       ;
        ;                                       ;
I2CCommn                                        ;
        PAGESEL I2CSIntPut                      ;
        movlw   000h                            ;Data1;
        call    I2CSIntPut                      ;
                                                ;
        PAGESEL I2CSIntPut                      ;
        movlw   001h                            ;Data2;
        call    I2CSIntPut                      ;
                                                ;
        PAGESEL I2CSIntPut                      ;
        movlw   002h                            ;Data3;
        call    I2CSIntPut                      ;
                                                ;
        PAGESEL I2CSIntPut                      ;
        movlw   003h                            ;Data4;
        call    I2CSIntPut                      ;
rechk                                           ;
        btfss   vI2CSIntStatus,I2CSTx           ;
        goto    I2CRx                           ;
                                                ;
        ;                                       ;
        ;                                       ;
        ;                                       ;
        ;                                       ;
        goto    rechk                           ;
                                                ;
I2CRx:                                          ;
        btfsc   vI2CSIntStatus,I2CSRxBufEmpty   ;
        goto    rechk                           ;
                                                ;
                                                ;
; To Receive from the Mastar                    ;
                                                ;
        PAGESEL I2CSIntGet                      ;
        call      I2CSIntGet                    ;Data is present in 'W' Register      
                                                ;
        goto      I2CRx                         ;
                                                ;
        ;                                       ;
        ;                                       ;
        ;                                       ;
        ;                                       ;
                                                ;
        goto      $                             ;
;-----------------------------------------------;
ISRHandler:                                     ;
                                                ;
	    movwf	DupW				            ;
	    swapf	STATUS,w			            ;
	    movwf	DupStat				            ;
        ;                                       ;
        PAGESEL I2CSIntISR                      ;
        call    I2CSIntISR                      ;
        ;                                       ;
        ;                                       ;
        ;                                       ;
	    swapf	DupStat,w			            ;
	    movwf	STATUS				            ;
	    swapf	DupW,f				            ;
	    swapf	DupW,w				            ;
        retfie                                  ;
                                                ;
;***********************************************;
      end                                       ;
;***********************************************;