136 lines
1.8 KiB
C
136 lines
1.8 KiB
C
#define F_CPU 7372800UL
|
|
#include <avr/io.h>
|
|
#include <util/delay.h>
|
|
#include <stdlib.h>
|
|
#include "i2c.h"
|
|
|
|
BYTE i2c_stop(void)
|
|
{
|
|
BYTE error = 0;
|
|
|
|
NULL_SCL();
|
|
I2C_DELAY();
|
|
NULL_SDA();
|
|
I2C_DELAY();
|
|
|
|
ONE_SCL();
|
|
I2C_DELAY();
|
|
ONE_SDA();
|
|
I2C_DELAY();
|
|
|
|
if((I2C_PIN & (1 << I2C_SDA)) == 0) error = 2;
|
|
if((I2C_PIN & (1 << I2C_SCL)) == 0) error |= 1;
|
|
I2C_DELAY();
|
|
I2C_DELAY();
|
|
I2C_DELAY();
|
|
I2C_DELAY();
|
|
|
|
return error;
|
|
}
|
|
|
|
void i2c_start(void)
|
|
{
|
|
NULL_SDA();
|
|
I2C_DELAY();
|
|
NULL_SCL();
|
|
I2C_DELAY();
|
|
}
|
|
|
|
|
|
void i2c_restart(void)
|
|
{
|
|
ONE_SDA();
|
|
I2C_DELAY();
|
|
ONE_SCL();
|
|
I2C_DELAY();
|
|
|
|
NULL_SDA();
|
|
I2C_DELAY();
|
|
NULL_SCL();
|
|
I2C_DELAY();
|
|
}
|
|
|
|
void i2c_init(void)
|
|
{
|
|
ONE_SDA();
|
|
ONE_SCL();
|
|
|
|
i2c_stop();
|
|
}
|
|
|
|
BYTE i2c_send_byte(BYTE data)
|
|
{
|
|
BYTE i;
|
|
BYTE ask = ACK;
|
|
|
|
for(i = 0; i < 8; i++)
|
|
{
|
|
if((data & 0x80) == 0)
|
|
{
|
|
NULL_SDA();
|
|
}
|
|
else
|
|
{
|
|
ONE_SDA();
|
|
}
|
|
I2C_DELAY();
|
|
ONE_SCL();
|
|
I2C_DELAY();
|
|
NULL_SCL();
|
|
|
|
data = (data << 1);
|
|
}
|
|
|
|
ONE_SDA();
|
|
I2C_DELAY();
|
|
ONE_SCL();
|
|
I2C_DELAY();
|
|
|
|
if((I2C_PIN & (1 << I2C_SDA)) == (1 << I2C_SDA))
|
|
{
|
|
ask = NACK;
|
|
}
|
|
else
|
|
{
|
|
ask = ACK;
|
|
}
|
|
|
|
NULL_SCL();
|
|
|
|
return ask;
|
|
}
|
|
|
|
BYTE i2c_read_byte(BYTE ask)
|
|
{
|
|
BYTE byte = 0;
|
|
BYTE i;
|
|
|
|
ONE_SDA();
|
|
|
|
for(i = 0; i < 8; i++)
|
|
{
|
|
byte = (byte << 1);
|
|
ONE_SCL();
|
|
I2C_DELAY();
|
|
if((I2C_PIN & (1 << I2C_SDA)) == (1 << I2C_SDA)) byte |= 0x01;
|
|
NULL_SCL();
|
|
I2C_DELAY();
|
|
}
|
|
|
|
if(ask == ACK)
|
|
{
|
|
NULL_SDA();
|
|
}
|
|
else
|
|
{
|
|
ONE_SDA();
|
|
}
|
|
I2C_DELAY();
|
|
ONE_SCL();
|
|
I2C_DELAY();
|
|
NULL_SCL();
|
|
I2C_DELAY();
|
|
ONE_SDA();
|
|
|
|
return byte;
|
|
} |