i2c_intf.c

HDMI anx9021的驱动

//********************************************************************************************
//********************************************************************************************
//***************************     Firmware for ANX9021     ***********************************
//********************************************************************************************
//********************************************************************************************

//******************************************************************************
//  ANALOGIX Company 
//  ANX9021 Firmware on AT89C51RC clean for customer
//  Version 1.51	2006/04/27
//******************************************************************************

#include <stdio.h>
#include "i2c_intf.h"

void print_byte(char *s, unsigned char b);



#define NOP_DELAY do { _NOP_; _NOP_; } while (0)


#define SCL_PULSE do { SCL_P = 1; NOP_DELAY; SCL_P = 0; NOP_DELAY; } while (0)

unsigned char i2c_dev_addr;

void i2c_init(void)
{
	SDA_P = 1;
	SCL_P = 1;
}

void i2c_send_start_bit(void)
{
	SDA_P = 0; NOP_DELAY;
	SCL_P = 0; NOP_DELAY;
}

void i2c_send_restart_bit(void)
{
	SDA_P = 1; NOP_DELAY;
	SCL_P = 1; NOP_DELAY;
	SDA_P = 0; NOP_DELAY;
	SCL_P = 0; NOP_DELAY;
}

void i2c_send_stop_bit(void)
{
	SDA_P = 0; NOP_DELAY;
	SCL_P = 1; NOP_DELAY;
	SDA_P = 1; NOP_DELAY;
}

void i2c_send_byte(unsigned char b)
{
	unsigned char i;
	
	for (i=0; i<8; i++) {
		ACC = b;
		SDA_P = ACC_7;
		SCL_PULSE;
		b = b << 1;
	}
}

unsigned char i2c_read_byte(void)
{
	unsigned char c, i;
	
	SDA_P = 1;
	
	for (i=0; i<8; i++) {
		SCL_P = 1; NOP_DELAY;
		
		ACC = c;
		ACC = ACC << 1;
		ACC_0 = SDA_P;
		c = ACC;
		SCL_P = 0; NOP_DELAY;
	}
	return c;
}

char i2c_read_ack(void)
{
	char result;
	
	SDA_P = 1; NOP_DELAY;
	SCL_P = 1; NOP_DELAY;
	result = SDA_P;
	SCL_P = 0; NOP_DELAY;
	SDA_P = 1; NOP_DELAY;
	return result;
}

void i2c_send_ack(char ack)
{
	SDA_P = ack; NOP_DELAY;
	SCL_P = 1; NOP_DELAY;
	SCL_P = 0; NOP_DELAY;
	SDA_P = 1; NOP_DELAY;
}


char i2c_write_reg(unsigned char offset, unsigned char d)
{
	i2c_send_start_bit();
	i2c_send_byte(i2c_dev_addr);
	if (i2c_read_ack()) {
		i2c_send_stop_bit();
		return 1;	// no device acknowledge
	}
	i2c_send_byte(offset);
	if (i2c_read_ack()) {
		i2c_send_stop_bit();
		return 2;	// device no accept the data, terminate transfer
	}
	i2c_send_byte(d);
	i2c_read_ack();
	i2c_send_stop_bit();
	return 0;
}

char i2c_write_p0_reg(unsigned char offset, unsigned char d)
{
	i2c_dev_addr = PORT0_ADDR;
	return i2c_write_reg(offset, d);
}

char i2c_write_p1_reg(unsigned char offset, unsigned char d)
{
	i2c_dev_addr = PORT1_ADDR;
	return i2c_write_reg(offset, d);
}

char i2c_read_reg(unsigned char offset, unsigned char *d)
{
	i2c_send_start_bit();
	i2c_send_byte(i2c_dev_addr);
	if (i2c_read_ack()) {
		i2c_send_stop_bit();
		return 1;	// no device acknowledge
	}
	i2c_send_byte(offset);
	if (i2c_read_ack()) {
		i2c_send_stop_bit();
		return 2;	// device no accept the data, terminate transfer
	}
	i2c_send_restart_bit();
	i2c_send_byte(i2c_dev_addr | 0x01);
	if (i2c_read_ack())
		return 1;	// no device acknowledge
	*d = i2c_read_byte();
	i2c_send_ack(1);
	i2c_send_stop_bit();
	return 0;
}

char i2c_read_p0_reg(unsigned char offset, unsigned char *d)
{
	i2c_dev_addr = PORT0_ADDR;
	return i2c_read_reg(offset, d);
}

char i2c_read_p1_reg(unsigned char offset, unsigned char *d)
{
	i2c_dev_addr = PORT1_ADDR;
	return i2c_read_reg(offset, d);
}