i2c+spi.c

Build ourself a MP3 Player

#include "i2c+spi.h"
// this file includes software I2C and SPI procedures for reading and writing...
// note the TRIS change in mp3_i2cRead()
 
void mp3_i2cStart() {
	set_tris_c(TRIS_C_I2CSEND);
	output_high(I2C_SDA);
	nop; nop;
	output_high(I2C_SCL);
	delay_us(3);
	output_low(I2C_SDA);
	delay_us(3);
	output_low(I2C_SCL);
}

void mp3_i2cStop() {
	set_tris_c(TRIS_C_I2CSEND);
	output_low(I2C_SDA);
	nop; nop;
	output_high(I2C_SCL);
	delay_us(3);
	output_high(I2C_SDA);
	delay_us(3);
}

byte mp3_i2cRead() {
	int i;
	byte data = 0;

	set_tris_c(TRIS_C_I2CRECV);
	for (i=0; i<8; i++) {
		output_high(I2C_SCL);
		delay_us(3);
		data <<= 1;
		data |= input(I2C_SDA);
		output_low(I2C_SCL);
		delay_us(3);
	}
	set_tris_c(TRIS_C_I2CSEND);
	output_low(I2C_SDA);
	nop; nop;
	output_high(I2C_SCL);
	delay_us(3);
	output_low(I2C_SCL);
	//printf("got 0x%x ", data);
	return data;
}

boolean mp3_i2cWrite(byte data) {
	signed int i;

	set_tris_c(TRIS_C_I2CSEND);

	for (i=7; i>=0; i--) {
		output_bit(I2C_SDA, bit_test(data, i));
		delay_us(3);
		output_high(I2C_SCL);
		delay_us(3);
		output_low(I2C_SCL);
		delay_us(3);
	}
	i = -1;
	set_tris_c(TRIS_C_I2CRECV);
	output_high(I2C_SCL);
	while (input(I2C_SDA) && i != 0) { nop; nop; i--; }
	output_low(I2C_SCL);
	if (i == 0) { return 0; }
	return 1;
}
/***************************************************************/

boolean mp3_spiwrite(byte data) {
	output_low(SPI_CLK);
	output_bit(SPI_SDO, bit_test(data, 7));
	output_high(SPI_CLK);
	nop; nop; nop;
	output_low(SPI_CLK);
	output_bit(SPI_SDO, bit_test(data, 6));
	output_high(SPI_CLK);
	nop; nop; nop;
	output_low(SPI_CLK);
	output_bit(SPI_SDO, bit_test(data, 5));
	output_high(SPI_CLK);
	nop; nop; nop;
	output_low(SPI_CLK);
	output_bit(SPI_SDO, bit_test(data, 4));
	output_high(SPI_CLK);
	nop; nop; nop;
	output_low(SPI_CLK);
	output_bit(SPI_SDO, bit_test(data, 3));
	output_high(SPI_CLK);
	nop; nop; nop;
	output_low(SPI_CLK);
	output_bit(SPI_SDO, bit_test(data, 2));
	output_high(SPI_CLK);
	nop; nop; nop;
	output_low(SPI_CLK);
	output_bit(SPI_SDO, bit_test(data, 1));
	output_high(SPI_CLK);
	nop; nop; nop;
	output_low(SPI_CLK);
	output_bit(SPI_SDO, bit_test(data, 0));
	output_high(SPI_CLK);
	nop; nop; nop;

}