Communication > CAN / LIN / RS485

RS485 and 18F452???

Hello.I wrote a program using RS485 [ PIC18F452/XTAL=20MHZ/mikroC for PIC compiler v5.1.0 ] to transfer the following arrays;

unsigned long int LOWD[]={1000,1000,1000,1000,1000,1000,500,500,500,100,4,44,40,7,5,5,5,400,500000,300000};

unsigned long int DHIGH[]={25000,25000,25000,25000,25000,25000,1200,1200,1200,290,11,60,280,1,33,33,33,3190,30000000,30000000};


from U2=PIC18F452 as a master to U1=PIC18F452 as a slave just at the begining of my main
and for one time and also to transfer the above arrays from U1=PIC18F452 slave for each
5 seconds to a PC.U2 is about 800 meters far from U1 and PC is 650 meters far from U2 and U2.

So,I wrote the following code for my PIC Master U2;

/*
*** Using RS485***

MCU: PIC18F452.
Oscillator: External, 20.000 MHz.
Ext. Modules: RS485 on PORTC.
SW: mikroC v5.1.
*/


char datx[39],dat[39];//Buffer for receving/sending messages.
char i,k, Iflag;


unsigned long int LOWD[]={1000,1000,1000,1000,1000,1000,500,500,500,100,4,44,40,7,5,5,5,400,500000,300000};

unsigned long int DHIGH[]={25000,25000,25000,25000,25000,25000,1200,1200,1200,290,11,60,280,1,33,33,33,3190,30000000,30000000};


//Function declration;

void MRSX485();


void MRSX485(){

UART1_Init(9600);//initialize uart module.
Delay_ms(100);

RS485Master_Init();//intialize mcu as master.

PORTB = 0;
PORTD = 0;
TRISB = 0;
TRISD = 0;

for(i=0;i<20;i++){
datx[i]=LOWD[i];
}

for(i=20;i<40;i++){
datx[i]=DHIGH[i];
}


k=0;
MX1:
dat[0] = datx[k];
dat[1] = datx[k+1];
dat[2] = datx[k+2];

dat[3] = 0;
dat[4] = 0; //*****What I should assign to dat[3] thru dat[6]?*****
dat[5] = 0;
dat[6] = 0;

Iflag = 0;

RS485Master_Send(dat,1,160);

PORTB = 0;
PORTD = 0;

dat[4] = 0;//ensure that message received flag is 0.
dat[5] = 0;//ensure that error flag is 0.

PIE1.RCIE = 1;//Enable interrupts.
INTCON.PEIE = 1;//On byte received.
PIE2.TXIE = 0;//Via UART (RS485).
INTCON.GIE = 1;


//**? **upon completed valid message receiving.
//**? **data[4] is set to 255.


if(dat[5]){ //if error detected, signal it by.
PORTD.F0 = 1;//setting PORTD.F0 to 1.
goto MX1;//Repeat sending that error messages again untill to be sent successfully.
}

if(dat[4]){ //if message received successfully.
dat[4] = 0;//clear message received flag.
PORTD.F1=1;//setting PORTD.F1 to 1.
Delay_ms(1);
K=K+3;
goto MX1; //Go for sending the remains.
}

}//~


// Interrupt routine
void interrupt() {
RS485Master_Receive(dat);
}//~

sbit rs485_rxtx_pin at RC6_bit;//set transcieve pin.
sbit rs485_rxtx_pin_direction at TRISC6_bit;//set transcieve pin directio.

void main() {

PORTA=0;//Clear portA.
TRISA=0XFF;//PortA is input.
PORTD=0;//Clear portD.
TRISD=0;//PortD is output.
PORTC=0;//Clear portC.
TRISC=0;//portC is output.
PORTB=0;//Clear portB.
TRISB=0XFF;//portB is input.
PORTE=0;//Clear portE.
TRISE=0;//PortE is Output. zzzz
TRISC = PORTC = 0;

// Only for PIC18F452 //

RCON.IPEN =1;//Enable priority levels on interrupts.
INTCON.INT0IE =1;//Enables the INT0 external interrupt.
INTCON2.INTEDG0 =0;//Interrupt on falling edge.
INTCON.RBIE =1;//Enables the RB Port change interrupt.

Delay_ms(400);

MRSX485();

}//~!

But that is not worked correctly.Would you please tell me what is wrong with my code?
Also,how can I sure that my arrays transferred correctly into U1 in a effective,fast and simply?
And how to write the Slave[U1] for that,to receive arrays send byU2?

Thanks,

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