/* 22:07 25 April 2013
* https://www.electro-tech-online.com/threads/i-have-problem-programming-pic18f4520-also-interfacing-with-74hc595-shift-regiter.134254/
* E:\Electronics\PIC Projects\Electrotech\saaiim 4525_74HC595_SPI\Source\Main V3.c
* MPLAB C18 v3.45
* PIC18F4520
*
* Read PORTA and send image to 74HC595 parallel outputs using SPI
*
* Tested OK 01:19 26/04/2013
*/
#include <p18F4520.h>
#include <delays.h>
/*------------------------------------------------------------------------*/
#pragma config OSC = INTIO67
#pragma config FCMEN = OFF
#pragma config IESO = OFF
#pragma config PWRT = OFF
#pragma config BOREN = OFF
#pragma config WDT = OFF
#pragma config PBADEN = OFF
#pragma config LPT1OSC = OFF
#pragma config MCLRE = ON
#pragma config STVREN = OFF
#pragma config LVP = OFF
#pragma config XINST = OFF
/*------------------------------------------------------------------------*/
#define rx_buffer_full (SSPSTATbits.BF)
/*------------------------------------------------------------------------*/
char null_data;
/*------------------------------------------------------------------------*/
void SPI_init (void);
/*------------------------------------------------------------------------*/
void main (void)
{
OSCCON = 0b01100010; // Fosc = 4MHz (Inst. clk = 1MHz)
ADCON1 = 0xF; // No analog, all digital i/o
TRISA = 0xff; // DIL switch inputs
LATA = 0x0;
SPI_init(); // Set up the SPI
/********* Start of main loop **********/
while(1)
{
SSPBUF = PORTA >> 6 | PORTA << 2 ; // SPI byte to be txd is on PORTA
while (!rx_buffer_full); // Wait until buffer is full (tx done)
null_data = SSPBUF; // Read buffer to clear BF flag
Delay10KTCYx(25);
}
}
/*------------------------------------------------------------------------*/
void SPI_init (void)
{
SSPSTAT = 0b10000000; // b7 = SMP: Sample bit
// b6 = CKE: SPI ClK Select bit
// b5-1 = I2C mode only
// b0 = BF: Buffer Full Status bit (rx mode only)
SSPCON1 = 0b00100000; // b7 = WCOL: Write collision detect
// b6 = SSPOV: Receive Overflow Indicator bit
// b5 = SSPEN: Synchronous Serial Port Enable
// b4 = CKP: Clock Polarity Select
// b3-0 = SSPM: Synchronous Serial Port Mode Select bits
TRISCbits.TRISC5 = 0; // [pic pin24] SPI data out
TRISCbits.TRISC3 = 0; // [pic pin18] SPI clock out
}