//
// spi.c
//


// System headers
#include <avr/io.h>

// Project headers
#include "spi.h"



//Oled is connected to alternate SPI pins
#define MOSI_bm 1<<2 //on port C
#define SCK_bm 1<<0 //on port C
#define SS_bm 1<<3 //on port A
#define SPI_PORT PORTC //We can now use SPI_PORT.DIR, .OUT etc.
#define SS_PORT PORTA //SS is on a different port

//We could also have defined bit positions for MOSI, SCL and SS.



void SPI_MasterInit()
{
	// Initialize the SPI port as master
	// You will need to set MOSI, SCK, SS (slave select) as outputs
	
	//Connect OLED to EXT3
	
	PORTMUX.CTRLB |= PORTMUX_SPI0_bm; //To use alternative SPI pins
	
	SPI_PORT.DIR |= MOSI_bm | SCK_bm; //Set pins as output
	SS_PORT.DIR |= SS_bm;

	SS_PORT.OUTSET = SS_bm; //Set SS high -> OLED inactive
	
	
	// Now enable SPI, Master and set clock rate
	
	SPI0.CTRLA |= SPI_ENABLE_bm | SPI_MASTER_bm; //Default clock divisor of 4 is fine
	
	

	//Make sure SS does not disable master mode (Possibly not required)
	SPI0.CTRLB |= SPI_SSD_bm;
}


void SPI_MasterTransmit(char cData)
{
	// First select the correct slave by setting its slave select (SS) LOW
	SS_PORT.OUTCLR = SS_bm;

	// Then start the transmission by assigning the data to the SPI data register
	SPI0.DATA = cData;

	// Now wait for the data transmission to complete by periodically checking the SPI status register
	//the SPI_IF and SPI_WRCOL is the only interrupt flag with a function in non-buffered mode.
	while(!(SPI0.INTFLAGS & SPI_IF_bm)){
		
	}
	SPI0.DATA; //Dummy read to clear flag

	// Finally set the slave select bit HIGH before leaving the function
	SS_PORT.OUTSET = SS_bm;
}