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soft_i2c.c
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soft_i2c.c
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/*
* File Name: soft_i2c.c
* Author: Siddharth Chandrasekaran
* Website : http://embedjournnal.com/
* Created on July 27, 2012, 12:12 PM
*/
#include "soft_i2c.h"
#include "delay.h"
unsigned char i2cReadByte(void)
{
unsigned char inByte, n;
i2cHighSda();
for (n=0; n<8; n++)
{
i2cHighScl();
if (SDA_PIN)
inByte = (inByte << 1) | 0x01; // msbit first
else
inByte = inByte << 1;
i2cLowScl();
}
return(inByte);
}
void i2cWriteByte(unsigned char outByte)
{
unsigned char n;
for(n=0; n<8; n++)
{
if(outByte&0x80)
i2cHighSda();
else
i2cLowSda();
i2cHighScl();
i2cLowScl();
outByte = outByte << 1;
}
i2cHighSda();
}
void i2cNack(void)
{
i2cHighScl();
i2cLowScl(); // bring data high and clock
}
void i2cAck(void)
{
i2cLowSda();
i2cHighScl();
i2cLowScl();
i2cHighSda(); // bring data low and clock
}
void i2c_start(void)
{
i2cLowScl();
i2cHighSda();
i2cHighScl();
i2cLowSda();
i2cLowScl(); // bring SDA low while SCL is high
}
void i2cStop(void)
{
i2cLowScl();
i2cLowSda();
i2cHighScl();
i2cHighSda(); // bring SDA high while SCL is high
}
void i2cHighSda(void)
{
SDA_DIR = 1; // bring SDA to high impedance
delayUs(5);
}
void i2cLowSda(void)
{
SDA_PIN = 0;
SDA_DIR = 0; // output a logic zero
delayUs(5);
}
void i2cHighScl(void)
{
SCL_DIR = 1; // bring SCL to high impedance
delayUs(5);
}
void i2cLowScl(void)
{
SCL_PIN = 0;
SCL_DIR = 0;
delayUs(5);
}