i2c.c

AVR单片机C语言程序设计实例精粹

//***************************************************************
// File Name : I2C.C
// Author    : Steaven
// Created   : 2008-06-09
// Modified  : 
// Revision  : V0.0
//***************************************************************

#include "includes.h" 

void Delayms(INT16U time)
{
	while(time--) NOP();
}

//I2C操作状态位,反映操作是否成功
INT8U bI2C_Ack = 0;

//引脚属性定义,便于移植
#define DIR_REG_I2C  DDRB
#define PORT_REG_I2C PORTB
#define PIN_REG_I2C  PINB
#define SCL_BIT_I2C  0
#define SDA_BIT_I2C  1

//***************************************************************
// Function    : I2C_Set_SDA
// Input       : data - SDA Pin Level
// Output      : none
// Description : Set SDA Pin Level.
//***************************************************************
void I2C_Set_SDA(INT8U data)
{
	if(data == 0)
	{
		PORT_REG_I2C &= ~(1 << SDA_BIT_I2C);
	}
	else
	{
		PORT_REG_I2C |= (1 << SDA_BIT_I2C);
	}
}

//***************************************************************
// Function    : I2C_Set_SCL
// Input       : data - SCL Pin Level
// Output      : none
// Description : Set SCL Pin Level.
//***************************************************************
void I2C_Set_SCL(INT8U data)
{
	if(data == 0)
	{
		PORT_REG_I2C &= ~(1 << SCL_BIT_I2C);
	}
	else
	{
		PORT_REG_I2C |= (1 << SCL_BIT_I2C);
	}
}

//***************************************************************
// Function    : I2C_Start_Condition
// Input       : none
// Output      : none
// Description : Generate a START Condition.
//***************************************************************
void I2C_Start_Condition(void)
{
	I2C_Set_SDA(1);
	I2C_Set_SCL(1);
	I2C_Set_SDA(0);
	I2C_Set_SCL(0);
}

//***************************************************************
// Function    : I2C_Stop_Condition
// Input       : none
// Output      : none
// Description : Generate a STOP Condition.
//***************************************************************
void I2C_Stop_Condition(void)
{
	I2C_Set_SDA(0);
	I2C_Set_SCL(1);
	I2C_Set_SDA(1);
}

//***************************************************************
// Function    : I2C_Send_Byte
// Input       : data - data to be transmitted
// Output      : none
// Description : Send a byte on I2C Bus with the MSB first.
//***************************************************************
void I2C_Send_Byte(INT8U data)
{
	INT8U cnt;
	for(cnt = 0;cnt < 8;cnt++)
	{
		if((data << cnt) & 0x80)
		{
			I2C_Set_SDA(1);
		}
		else
		{
			I2C_Set_SDA(0);
		}
		I2C_Set_SCL(1);
		I2C_Set_SCL(0);
	}
	I2C_Set_SDA(1);
    I2C_Set_SCL(1);
	DIR_REG_I2C &= ~(1 << SDA_BIT_I2C);
	if(PIN_REG_I2C & (1 << SDA_BIT_I2C))
	{
		bI2C_Ack = 0;
	}
	else
	{ 
		bI2C_Ack = 1;
	}
	I2C_Set_SCL(0);
	DIR_REG_I2C |= (1 << SDA_BIT_I2C);
	Delayms(100);
}

//***************************************************************
// Function    : I2C_Receive_Byte
// Input       : none
// Output      : Receive a byte from I2C Bus
// Description : Receive a byte on I2C Bus with the MSB first.
//***************************************************************
INT8U I2C_Receive_Byte(void)
{
	INT8U data = 0;
	INT8U cnt = 0;
	DIR_REG_I2C &= ~(1 << SDA_BIT_I2C);
	PORT_REG_I2C |= (1 << SDA_BIT_I2C);
	for(cnt = 0; cnt < 8;cnt++)
	{
        I2C_Set_SCL(0);
        I2C_Set_SCL(1);
        data = data << 1;
		if(PIN_REG_I2C & (1 << SDA_BIT_I2C))
		{
			data |= 0x01;
		}
	}
	I2C_Set_SCL(0);
	DIR_REG_I2C |= (1 << SDA_BIT_I2C);
	return(data);
}

//***************************************************************
// Function    : I2C_Ack
// Input       : ack - Whether to ACK the transmitter
// Output      : none
// Description : Acknowledge the transmitter with 0 or 1
//***************************************************************
void I2C_Ack(INT8U ack)
{
	if(ack == 0)
	{
		I2C_Set_SDA(0);
	}
	else
	{
		I2C_Set_SDA(1);
	}
	I2C_Set_SCL(1);
	I2C_Set_SCL(0);
}

//***************************************************************
// Function    : I2C_Send_Data_without_SubAddress
// Input       : bDevice - Slave Device with a I2C Address,
//               bData   - Data to be transmitted 
// Output      : I2C Operation Status - Success(1)/Fail(0)
// Description : Transmit a data to Slave without SubAddress
//***************************************************************
INT8U I2C_Send_Data_without_SubAddress(INT8U bDevice,INT8U bData)
{
	I2C_Start_Condition();
	I2C_Send_Byte(bDevice);
	if(bI2C_Ack == 0)
	{
		return(0);
	}
	I2C_Send_Byte(bData);
	if(bI2C_Ack == 0)
	{
		return(0);
	}
	I2C_Stop_Condition();
	return(1);
}

//***************************************************************
// Function    : I2C_Send_Data_with_SubAddress
// Input       : bDevice  - Slave Device with a I2C Address,
//               bAddress - SubAddress of the Slave,
//               bData    - Data to be transmitted 
// Output      : I2C Operation Status - Success(1)/Fail(0)
// Description : Transmit a data to Slave with SubAddress
//***************************************************************
INT8U I2C_Send_Data_with_SubAddress(INT8U bDevice,INT8U bAddress,INT8U bData)
{
	I2C_Start_Condition();
   	I2C_Send_Byte(bDevice);
   	if(bI2C_Ack == 0)
   	{
   		return(0);
   	}
   	I2C_Send_Byte(bAddress);
    if(bI2C_Ack == 0)
    {
    	return(0);
    }
    I2C_Send_Byte(bData);
    if(bI2C_Ack == 0)
    {
    	return(0);
    }
  	I2C_Stop_Condition();
  	return(1);
}

//***************************************************************
// Function    : I2C_Send_String_with_SubAddress
// Input       : bDevice  - Slave Device with a I2C Address,
//               bAddress - SubAddress of the Slave,
//               ptr      - Pointer to the data buffter 
// Output      : I2C Operation Status - Success(1)/Fail(0)
// Description : Transmit a data to Slave with SubAddress
//***************************************************************
INT8U I2C_Send_String_with_SubAddress(INT8U bDevice,INT8U bAddress,INT8U *ptr,INT8U bLength)
{
	INT8U cnt;
	I2C_Start_Condition();																		
	I2C_Send_Byte(bDevice);																		
	if(bI2C_Ack == 0)																		
	{																		
		return(0);																		
	}																		
	I2C_Send_Byte(bAddress);																		
  	if(bI2C_Ack == 0)																		
	{																		
		return(0);																		
	}	
	for(cnt = 0;cnt < bLength;cnt++)
	{
		I2C_Send_Byte(*ptr++);
		if(bI2C_Ack == 0)																		
		{																		
			return(0);																		
		}
	}
	I2C_Stop_Condition();
	return(1);
}

//***************************************************************
// Function    : I2C_Receive_Data_without_Address
// Input       : bDevice  - Slave Device with a I2C Address,
//               ptr      - Pointer to the receive data buffter 
// Output      : I2C Operation Status - Success(1)/Fail(0)
// Description : Receive N data from Slave without SubAddress
//***************************************************************
INT8U I2C_Receive_Data_without_SubAddress(INT8U bDevice,INT8U *ptr)
{
	I2C_Start_Condition();
	I2C_Send_Byte(bDevice | 0x01);
    if(bI2C_Ack == 0)
    {
    	return(0);
    }
    *ptr = I2C_Receive_Byte();
    I2C_Ack(1);
    I2C_Stop_Condition();
    return(1);
}

//***************************************************************
// Function    : I2C_Recive_String_with_AddressIRcvStr
// Input       : bDevice  - Slave Device with a I2C Address,
//               bAddress - SubAddress of the Slave,
//               ptr      - Pointer to the receive data buffter 
// Output      : I2C Operation Status - Success(1)/Fail(0)
// Description : Receive N data from Slave with SubAddress
//***************************************************************
INT8U I2C_Recive_String_with_SubAddress(INT8U bDevice,INT8U bAddress,INT8U *ptr,INT8U bLength)
{
	INT8U cnt = 0;
	I2C_Start_Condition();
	I2C_Send_Byte(bDevice);
	if(bI2C_Ack == 0)
	{
		return(0);
	}
	I2C_Send_Byte(bAddress);
    if(bI2C_Ack == 0)
	{
		return(0);
	}
	I2C_Start_Condition();
	I2C_Send_Byte(bDevice | 0x01);
	if(bI2C_Ack == 0)
	{
		return(0);
	}
	for(cnt = 0;cnt < bLength - 1;cnt++)
	{
		*ptr++ = I2C_Receive_Byte();
		I2C_Ack(0);
	}
	*ptr = I2C_Receive_Byte();
	I2C_Ack(1);
	I2C_Stop_Condition();
	return(1);
}

//=========================END OF FILE=========================//