SR/SPI w/ PIC16f819

/* Place these things in a config header */
#include <htc.h>
#include "delay.h"
__CONFIG(MCLRE_OFF & CP_OFF & WDTE_OFF & BOREN_OFF & FOSC_INTOSCCLK);

/* :) */
#include "delay.c"

/* Probably okay macros */
#define SET_BIT(p,n) ((p) |=   (1) << (n))
#define CLR_BIT(p,n) ((p) &= ~((1) << (n)))
#define TOG_BIT(p,n) ((p) ^=   (1) << (n))
#define CHK_BIT(p,n) ((p) &   ((1) << (n)))

/* When in a library, use ifdefs to make these default but option pin mappings maybe  */
/* SPI Pins */
#define SPI_SDI     PORTBbits.RB1
#define SPI_SDO     PORTBbits.RB2
#define SPI_CS      PORTBbits.RB3
#define SPI_CLK     PORTBbits.RB4

/* SR Pins..figure something out later */
#define SR_LAT     PORTBbits.RB5
#define SR_HSCP    PORTBbits.RB6
#define SR_HTCP    PORTBbits.RB7

void spiInit() {
    SET_BIT(TRISB, SPI_SDI);
    CLR_BIT(TRISB, SPI_SDO);
    CLR_BIT(TRISB, SPI_CLK);
    CLR_BIT(TRISB, SPI_CS);

    SSPCON = 0;                    // first disable port if it was still running
    SSPSTAT = 0;                   // Reset all status flags (there are some R/W bits)
    SSPCON = (1<<5) | (1<<1);      // enable port, SPI mode Fosc/64
}

void srInit() {
    SET_BIT(TRISB, SR_LAT);
}

unsigned char spiTxRx(unsigned char byteOut) {
    SSPBUF = byteOut;                 // Write to buffer to start a transmit.
    while((SSPSTAT & (1 << 0)) == 0); // Wait till buffer indicator says a receive has been completed
    return SSPBUF;                    // Read the buffer for the received byte.
}

void srTx(char byteIn) {
    for(int i = 0; i < 8; i++) {
        /* Transmit byte, ignoring no return */
        spiTxRx(byteIn);

        /* Pulse LATh to transfer shift to storage registers. */
        SR_LAT = 0;
        SR_LAT = 1;
    }
}

/* ------------- MAIN PROGRAM -------------------*/
void main() {
    spiInit();
    srInit();

    /* Display an LED binary counter as a test */
    SPI_CS = 0;
    for(int i = 0; i < 255; i++) {
        srTx(i);
        DelayMs(100);
    }
    SPI_CS = 1;

}