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

void spi_init(void) {
	SSPSTAT = 0x40;
	SSPCON1 = 0x2a;
	SSPADD = 39; // 200 kHz @ 32MHz

	SPI_SDI = 0;
	SPI_SCK = 0;
	SPI_SDO = 0;

	SPI_SDI_TRIS = 1;
	SPI_SCK_TRIS = 0;
	SPI_SDO_TRIS = 0;

	SSPCLKPPS = SPI_SCK_PPS_IN;
	SSPDATPPS = SPI_SDI_PPS;

	SPI_SCK_PPS_OUT = 0x21;
	SPI_SDO_PPS = 0x23;
}

uint8_t spi_exchange(uint8_t data) {
	SSPCON1bits.WCOL = 0;
	SSPBUF = data;
	while (!SSPSTATbits.BF);
	return SSPBUF;
}

uint8_t spi_exchange_buffer(uint8_t *in, uint8_t buflen, uint8_t *out) {
	uint8_t written = 0;

	if (buflen != 0) {
		if (in != NULL) {
			while (written < buflen) {
				if (out == NULL)
					spi_exchange(in[written]);
				else
					out[written] = spi_exchange(in[written]);
				written++;
			}
		} else if (out != NULL)
			while (written < buflen)
				out[written++] = spi_exchange(DUMMY_DATA);
	}

	return written;
}

inline bool spi_is_buffer_full(void) {
	return SSPSTATbits.BF;
}

inline bool spi_has_write_collision_occured(void) {
	return SSPCON1bits.WCOL;
}

inline void spi_clear_write_collision_status(void) {
	SSPCON1bits.WCOL = 0;
}