SPI Bus - 3 wire bus with shift bit register using XC8 MPLAB

/* All  about the  spi bus  and how to implement this  in xc8 *
 * File:   spi.h
 * Author: Mark Harrington
 *
 * Created on 18 May 2021, 15:34
 */


/*Diagram  of hardware Link here below */



/* ******************************* https://photos.app.goo.gl/HpHcyLBu4NtDA3sb8 ************************************/

#ifndef SPI_H
#define	SPI_H

/* MD Harrington */


#pragma config FOSC = INTOSCIO  // Oscillator Selection bits (INTRC oscillator; port I/O function on both RA6/OSC2/CLKO pin and RA7/OSC1/CLKI pin)
#pragma config WDTE = OFF       // Watchdog Timer Enable bit (WDT disabled)
#pragma config PWRTE = OFF      // Power-up Timer Enable bit (PWRT disabled)
#pragma config MCLRE = OFF      // RA5/MCLR/VPP Pin Function Select bit (RA5/MCLR/VPP pin function is digital I/O, MCLR internally tied to VDD)
#pragma config BOREN = OFF      // Brown-out Reset Enable bit (BOR disabled)
#pragma config LVP = OFF        // Low-Voltage Programming Enable bit (RB3 is digital I/O, HV on MCLR must be used for programming)
#pragma config CPD = OFF        // Data EE Memory Code Protection bit (Code protection off)
#pragma config WRT = OFF        // Flash Program Memory Write Enable bits (Write protection off)
#pragma config CCPMX = RB0      // CCP1 Pin Selection bit (CCP1 function on RB0)
#pragma config CP = OFF         // Flash Program Memory Code Protection bit (Code protection off)

// CONFIG2
#pragma config FCMEN = OFF      // Fail-Safe Clock Monitor Enable bit (Fail-Safe Clock Monitor disabled)
#pragma config IESO = OFF       // Internal External Switchover bit (Internal External Switchover mode disabled)

// #pragma config statements should precede project file includes.
// Use project enums instead of #define for ON and OFF.

#include <xc.h>

/* Define clock  frequency  required  for delay  functions */


#define _XTAL_FREQ 8000000

#define  DATA   PORTAbits.RA0
#define  CLOCK  PORTAbits.RA1
#define  LATCH  PORTAbits.RA2


void clockdata(void);
void latchdata(void);


#ifdef	__cplusplus
extern "C" {
#endif

/* anything c ++  goes here */




#ifdef	__cplusplus
}
#endif

#endif	/* SPI_H */


/* Main Method  for doing this is below */

/*
 * File:   main.c
 * Author: mark Harrington
 *
 * Created on 17 May 2021, 17:17
 */

#include "spi.h"

// spi functions
void clockdata(void){

    CLOCK = 1 ;
     __delay_ms(5);
    CLOCK =0 ;


}


void latchdata(void){
   LATCH =1 ;
   __delay_ms(5);
   LATCH=0 ;

}

int main(int argc, char** argv) {



    TRISA=0x0 ;    // set port direction
    ANSEL= 0x0;    // digital out only
    OSCCON=0b01110100;    //osccon set to 8 megs
    PORTA=0x00 ;

    CLOCK =0 ;
    LATCH =0 ;


    unsigned char b = 0x01 ;

        while (1){

            for( unsigned int  i = 0;i <8 ;i++)
            {
                DATA = (unsigned char)(b<<i) ; // must cast this to  char for correct conversion
                __delay_ms(200);
                clockdata() ;
                latchdata() ;

            }
            DATA = b ;
        }

}