iiccore.c

7寸TFT电视的源程序

/*
	This file is should not add to project.It should include by other .c/.cpp  file.Before include this file
	you should add the define for :	
		iic_ClrSda(),	iic_SetSda(),	
		iic_ClrScl(),	iic_SetScl(),
		iic_GetSda()
*/
#if 0
#define iic_Delay()
#else
static void iic_Delay()
{
	unsigned char i=0;
	while(i<I2C_DELAY_TIME) i++;
}
#endif

/*************************************************************
	Issue a START condition to I2C 
**************************************************************/
static void iic_StartCode()
{
	iic_SetSda();		// both = 1
	iic_SetScl();		// both = 1

	iic_Delay();

	iic_ClrSda();		// SDA = 0
	iic_Delay();

	iic_ClrScl();		// SCL = 0
	iic_Delay();
}

/*******************************************************************
	Issue a STOP condition to I2C
*******************************************************************/
static void iic_StopCode()
{
	iic_ClrSda();				// SDA = 0
	iic_Delay();

	iic_SetScl();				// SCL = 1
	iic_Delay();

	iic_SetSda();				// SDA = 1
	iic_Delay();
}

/*******************************************************************
	Issue a Ack command to I2C 
*******************************************************************/
static void iic_SendAck()
{
	iic_ClrSda();
	iic_Delay();

	iic_SetScl();
	iic_Delay();
	iic_ClrScl();
	iic_Delay();
}

/*******************************************************************
	Issue a UnAck command to I2C 
*******************************************************************/
static void iic_SendUnack()
{
	iic_SetSda();
	iic_Delay();

	iic_SetScl();
	iic_Delay();
	iic_ClrScl();						// SCL = 0
	iic_Delay();
}

/*******************************************************************
	Verify ACK command from slave after send a data out to I2C 
*******************************************************************/
static unsigned char iic_CheckAck()
{
	unsigned char i;
	unsigned char ack;

	iic_SetSda();
	iic_Delay();
	iic_SetScl();
	iic_Delay();

	for(i=0; i< CHECK_I2C_ACK_TIME; i++)
	{
		ack = iic_GetSda();
		if(!ack){
			iic_ClrScl();
			return TRUE;
		}
		iic_Delay();
	}
	iic_StopCode();
	return FALSE;
}

/*******************************************************************
	Get a data from I2C 
*******************************************************************/
static unsigned char iic_GetData()
{
	unsigned char val,i;
	unsigned char tmp;

	val = 0;

//we should set SDA = 1,
//if not the chip can't pull up and we will receive zero.
	iic_SetSda();				// SDA = 1
	for(i=0;i<8;i++) {
		iic_Delay();

		val <<= 1;
		tmp = iic_GetSda();
		if (tmp)
			val = val | 0x1;
		iic_Delay();

		iic_SetScl();			// SCL = 1
		iic_Delay();

		iic_ClrScl();			// SCL = 0
		iic_Delay();
	}

	return val;
}

/*************************************************************
	Send a DATA out to I2C 
**************************************************************/
static void iic_SendData(unsigned char val)
{
	unsigned char i;

	for(i=0;i<8;i++) 
	{
		if( val & 0x80 )
			iic_SetSda();		// SDA = 1
		else
			iic_ClrSda();		// SDA = 0
		val <<= 1;
		iic_Delay();

		iic_SetScl();			// SCL = 1
		iic_Delay();

		iic_ClrScl();			// SCL = 0
		iic_Delay();
	}
}