i2c.c

dvr

/*
********************************************************************************
*
* (c) Copyright 2002, Vineyard Technologies, Inc.
*
* Filename : i2c.c
* Programmer(s): Steve KyeongHyeon Lee
* Created : 2003/05/07
* Modified :
*
* Description : 
********************************************************************************
*/
#include "types.h"

#include "8052reg.h"
#include "gio.h"
#include "i2c.h"

// try to make I2C clock around 100KHz when using 40MHz MCU clock

//------------------------------------------------------------------------------
// I2C Peripheral Function Prototypes
//------------------------------------------------------------------------------

void i2c_delay(void)
{
	idata u8 m=1;
	
	return;
}

void i2c_delay2(u8 delay_duration)
{
	xdata u8 i;
	for(i=0;i<delay_duration;i++);
}

//------------------------------------------------------------------------------
//
//------------------------------------------------------------------------------
void i2c_pkt_write(u8 ipw_channel, u8 ipw_regidx, u8 ipw_regval)
{
	i2c_start();
	i2c_write(ipw_channel);
	i2c_write(ipw_regidx);
	i2c_write(ipw_regval);
	i2c_stop();
}

//------------------------------------------------------------------------------
//
//------------------------------------------------------------------------------
u8 i2c_pkt_read(u8 ipr_channel, u8 ipr_regidx)
{
	xdata u8 ipr_data_in;

	i2c_start();
	i2c_write(ipr_channel);
	i2c_write(ipr_regidx);
	i2c_stop();

	i2c_start();
	i2c_write(ipr_channel+1);
	ipr_data_in = i2c_read();
	i2c_stop();
	return ipr_data_in;
}

//------------------------------------------------------------------------------
// I2C Functions - Bit Banged
//------------------------------------------------------------------------------
void i2c_start(void)
{
	SDATA = HIGH;							// Set data line high
	i2c_delay(); //(10);

	SCLK = HIGH;							// Set clock line high
	i2c_delay(); //(10);

	SDATA = LOW;							// Set data line low (START SIGNAL)
	i2c_delay(); //(4);
	
	SCLK = LOW;								// Set clock line low
	i2c_delay(); //(4);
	
}

//------------------------------------------------------------------------------
//
//------------------------------------------------------------------------------
void i2c_stop (void)
 {
	xdata u8 is_input_var;

	SCLK  = LOW;	   						// Set clock line low .. need more delay
	i2c_delay2(1);

	SDATA = LOW;							// Set data line low
	i2c_delay(); //(4);
	
	SCLK  = HIGH;							// Set clock line high
	i2c_delay(); //(4);
	
	SDATA = HIGH;							// Set data line high (STOP SIGNAL)
	is_input_var = SDATA;						// Put port pin into HiZ
}

//------------------------------------------------------------------------------
//
//------------------------------------------------------------------------------
void i2c_write (u8 iw_output_data)
{
	u8 iw_index;

	for(iw_index = 0; iw_index < 8; iw_index++)  	// Send 8 bits to the I2C Bus
	{
		SDATA = ((iw_output_data & 0x80) ? 1 : 0);
     	iw_output_data  <<= 1;            		// Shift the byte by one bit
		i2c_delay(); //(3);

		SCLK = HIGH;   		        		// Clock the data into the I2C Bus
		i2c_delay(); //(4);

		SCLK = LOW;
		i2c_delay(); //(2);
	}

	// need more delay
	i2c_delay2(1);
	iw_index = SDATA;			  		// Put data pin into read mode1

	SCLK = HIGH;   		           		// Clock the ACK from the I2C Bus
  	i2c_delay(); //(7);

	SCLK = LOW;
  	i2c_delay(); //(4);
}

//------------------------------------------------------------------------------
//
//------------------------------------------------------------------------------
u8 i2c_read (void)
{
	u8 ir_index;
	u8 ir_input_data;

  	ir_index = SDATA;							// Put data pin into read mode
	ir_input_data = 0x00;

	for(ir_index = 0; ir_index < 8; ir_index++)  	// Send 8 bits to the I2C Bus
	{
		ir_input_data <<= 1;					// Shift the byte by one bit
      	ir_input_data |= SDATA; 		   		// Input the data from the I2C Bus
		SCLK = HIGH;           				// Clock the data into the I2C Bus
		i2c_delay(); //(4);

		SCLK = LOW;
		i2c_delay(); //(3);
	}

	// need more delay
	i2c_delay2(1);

	ir_index = SDATA;					// Put data pin into read mode1
	SCLK = HIGH;						// Clock the ACK from the I2C Bus
	i2c_delay(); //(7);

	SCLK = LOW;
	i2c_delay(); //(4);

	return ir_input_data;
}

u8 I2C_RxByte(u8 bSLA, u8 bREG)// 20051020 add for BIT1601
{
        xdata u8 ipr_data_in;

	i2c_start();
	i2c_write(bSLA);
	i2c_write(bREG);

        i2c_start();
        i2c_write(bSLA | 0x01);
        
        ipr_data_in = i2c_read();
	i2c_stop();
        return ipr_data_in;
}