Question for SPI on 18f8722

[wilsonz91]

Question for SPI

Hello,

i am trying to interface two PIC18F8722 with each other using SPI. I manage to get it going (one way communication) doing a simple countdown but there some problems which I could not find a solution to.

here is the code for:

master

#include <p18f8722.h>    
#include "spi.h"
#include <delays.h>

void main()
{
	unsigned char a = 0xFF,b;

	TRISC = 0xD7;
	TRISF = 0x00;
	
	OpenSPI1(SPI_FOSC_4, MODE_01, SMPMID);
	
	while(1){
		WriteSPI1(a);
		while(!DataRdySPI());
		b=ReadSPI1();
		LATF = b;
		Delay10KTCYx(200);
		
		
		a--;

		if (a==0)
			a = 0xFF;
	}
}

Slave:

#include <p18f8722.h>     
#include "spi.h"

void main()
{
	unsigned char a;
	
	TRISC = 0x1F;
	TRISF = 0x00;
	
	OpenSPI1(SLV_SSOFF, MODE_01, SMPMID);
	LATF = ReadSPI1();                                       [I]//without this line, SPI would not work. why? wouldn't having this line in the while loop be sufficient?[/I]

	while(1){
		while(!DataRdySPI1());
		a = ReadSPI1();
		LATF = a;
		a--;
		WriteSPI1(a);

	if (a == 0)
		a = 0xFF;
	}
}

Connections are:
master slave
RC3 -> RC3 (SCK)
RC5 -> RC4 (master out to slave in)
RC4 -> RC5 (slave out to master in)

What I am trying to achieve is two-way communication where both master and slave would be counting down eg master-255, slave-254,master-253,slave,252.

Please advice, thank you =)

 

[parthiv2eng]

Are you doing simulation on MPSIM or on hardware?
BTW I would enable CS line before writing any code and disable after transfer done.