PIC Lesson: Modbus

PIC Modbus

/*
Project: Modbus RTU Lesson
Programmer: Shahrulnizam Mat Rejab
PIC (Crystal Frequency):
PIC16F877A (20MHz), PIC16F887 (20MHz), PIC16F1939 (Internal 32MHz)
PIC18F4520 (10MHz), PIC18F4550 (10MHz), PIC18F46K22 (Internal 16MHz)
Compiler: HI-TECH C for PIC10/12/16 V9.83, PIC18 V9.80
Last Modified: 1 January 2014
Website: http://shahrulnizam.com
*/

#define	TIMER0
#define	ADC
#define	UART
#define	HD44780
#define	SHAHRULNIZAM
#define SLAVE_ID	1

#include "LibraryHardware.h"
#include "LibraryPeripheral.h"
#include "LibraryUniversalDisplay.h"
#include "LibraryModbus.h"

char rep,z,request[40],response[40],bitt[20];
unsigned int address[40],counter;

static void interrupt isr(void)
{char i;
if(RCIF==1){
    counter=0;
    request[z]=uart1_read();
    if(z<39) z++;}
if(TMR0IF==1){
    TMR0IF=0;
    counter++;
    if(counter==1000){
        rep=1;
        z=0;}
    if(counter==20000){
        for(i=0;i<=9;i++) request[i]=0;
        for(i=0;i<=9;i++) response[i]=0;}}
}

void setup()
{
initialize();
TRISA=0b00000001;
TRISB=0b00000000;
TRISC=0b10000000;
TRISD=0b00000000;
TRISE=0b00000000;
timer0(0);
enable_tmr0();
enable_rc1();
BUZZER=1;
uart1_init(9600);
lcd_init();
lcd_goto(0,0);
lcd_string("  MODBUS PROTOCOL   ");
while(1) loop();
}

void loop()
{int i;
address[0]=adc_read(0);

lcd_goto(0,1);
for(i=0;i<=6;i++){
    lcd_number(request[i],HEX,2);
    if(i!=6) lcd_write(' ');}

lcd_goto(0,2);
for(i=7;i<=13;i++){
    lcd_number(request[i],HEX,2);
    if(i!=13) lcd_write(' ');}

lcd_goto(0,3);
lcd_string("ADD0=");
lcd_number(address[0],10,4);
lcd_string(" ADD1=");
lcd_number(address[1],10,5);

if(rep==1){
    rep=0;
    modbus_slave(address,bitt,request,response);}
}