【蓝桥杯嵌入式】5_IIC&EEPROM

1、原理图

顺便指出了该器件的地址。

24C02是2Kbits容量，一共256字节，所以可寻址范围是0x00~0xFF

2、源代码

实验：实现每重启一次Data数据+1

读代码指令：

使用了官方提供的IO口模拟IIC时序代码（或许我们可以利用这些代码的初始化部分让自己在赛场上快速初始化IO）。
main.c:

#include "HeadFile.h"

//Main Body
int main(void)
{
	u8 Str[20];
	u8 Dat = 0;
	
	
	SysTick_Config(SystemCoreClock/1000);//DelayInit
	LEDInit();
	IICInit();
	Delay_Ms(200);
	
	STM3210B_LCD_Init();
	LCD_Clear(Blue);
	LCD_SetBackColor(Blue);
	LCD_SetTextColor(White);
	
	Dat = EERead(0x01);
	sprintf((char *)Str,"Data = %d",Dat);
	EEWrite(0x01, (++Dat));
	
	LCD_DisplayStringLine(Line5,Str);
	while(1);
}

IIC.h:

#ifndef IIC_H_
#define IIC_H_

void IICInit(void);
void delay1(unsigned int n);

void I2CStart(void);
void I2CStop(void);
void I2CSendAck(void);
void I2CSendNotAck(void);
unsigned char I2CWaitAck(void);

void I2CSendByte(unsigned char cSendByte);
unsigned char I2CReceiveByte(void);

//For EEPROM
void EEWrite(u8 Addr,u8 Dat);
u8	 EERead(u8 Addr);

#endif

IIC.c:

#include "HeadFile.h"


/** I2C 总线接口 */
#define I2C_PORT GPIOB
#define SDA_Pin	GPIO_Pin_7
#define SCL_Pin GPIO_Pin_6

#define FAILURE 0
#define SUCCESS 1

//配置SDA信号线为输入模式
void SDA_Input_Mode()
{
	GPIO_InitTypeDef GPIO_InitStructure;

	GPIO_InitStructure.GPIO_Pin = SDA_Pin;
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_2MHz;
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPD;	 

	GPIO_Init(I2C_PORT, &GPIO_InitStructure);
}

//配置SDA信号线为输出模式
void SDA_Output_Mode()
{
	GPIO_InitTypeDef GPIO_InitStructure;

	GPIO_InitStructure.GPIO_Pin = SDA_Pin;
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_2MHz;
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;

	GPIO_Init(I2C_PORT, &GPIO_InitStructure);
}

//
void SDA_Output( uint16_t val )
{
	if ( val ) {
		GPIO_SetBits(I2C_PORT,SDA_Pin);
	} else {
		GPIO_ResetBits(I2C_PORT,SDA_Pin);
	}
}

//
void SCL_Output( uint16_t val )
{
	if ( val ) {
		GPIO_SetBits(I2C_PORT,SCL_Pin);
	} else {
		GPIO_ResetBits(I2C_PORT,SCL_Pin);
	}
}

//
uint8_t SDA_Input()
{
	return GPIO_ReadInputDataBit( I2C_PORT, SDA_Pin);
}

//延时程序
void delay1(unsigned int n)
{
	unsigned int i;
	for ( i=0;i<n;++i);
}

//I2C总线启动
void I2CStart(void)
{
	SDA_Output(1);delay1(500);
	SCL_Output(1);delay1(500);
	SDA_Output(0);delay1(500);
	SCL_Output(0);delay1(500);
}

//I2C总线停止
void I2CStop(void)
{
	SCL_Output(0); delay1(500);
	SDA_Output(0); delay1(500);
	SCL_Output(1); delay1(500);
	SDA_Output(1); delay1(500);

}

//等待应答
unsigned char I2CWaitAck(void)
{
	unsigned short cErrTime = 5;
	SDA_Input_Mode(); 
	delay1(500);
	SCL_Output(1);delay1(500);
	while(SDA_Input())
	{
		cErrTime--;
		delay1(500);
		if (0 == cErrTime)
		{
			SDA_Output_Mode();
			I2CStop();
			return FAILURE;
		}
	}
	SDA_Output_Mode();
	SCL_Output(0);delay1(500); 
	return SUCCESS;
}

//发送应答位
void I2CSendAck(void)
{
	SDA_Output(0);delay1(500);
	delay1(500);
	SCL_Output(1); delay1(500);
	SCL_Output(0); delay1(500);

}

//
void I2CSendNotAck(void)
{
	SDA_Output(1);
	delay1(500);
	SCL_Output(1); delay1(500);
	SCL_Output(0); delay1(500);

}

//通过I2C总线发送一个字节数据
void I2CSendByte(unsigned char cSendByte)
{
	unsigned char  i = 8;
	while (i--)
	{
		SCL_Output(0);delay1(500); 
		SDA_Output(cSendByte & 0x80); delay1(500);
		cSendByte += cSendByte;
		delay1(500); 
		SCL_Output(1);delay1(500); 
	}
	SCL_Output(0);delay1(500); 
}

//从I2C总线接收一个字节数据
unsigned char I2CReceiveByte(void)
{
	unsigned char i = 8;
	unsigned char cR_Byte = 0;
	SDA_Input_Mode(); 
	while (i--)
	{
		cR_Byte += cR_Byte;
		SCL_Output(0);delay1(500); 
		delay1(500); 
		SCL_Output(1);delay1(500); 
		cR_Byte |=  SDA_Input(); 
	}
	SCL_Output(0);delay1(500); 
	SDA_Output_Mode();
	return cR_Byte;
}

//I2C总线初始化
void IICInit()
{
	GPIO_InitTypeDef GPIO_InitStructure;

	RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);

	GPIO_InitStructure.GPIO_Pin = SDA_Pin | SCL_Pin;
  	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_2MHz;
  	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;	 // **

  	GPIO_Init(I2C_PORT, &GPIO_InitStructure);

}

//For EEPROM

void EEWrite(u8 Addr,u8 Dat)
{
	I2CStart();
	I2CSendByte(0xA0);//器件地址
	I2CWaitAck();
	I2CSendByte(Addr);//内存地址
	I2CWaitAck();
	I2CSendByte(Dat);
	I2CWaitAck();
	I2CStop();
	
}

u8 EERead(u8 Addr)
{
	u8 temp = 0;
	
	I2CStart();
	I2CSendByte(0xA0);//器件地址
	I2CWaitAck();
	I2CSendByte(Addr);//内存地址
	I2CWaitAck();
	
	I2CStart();
	I2CSendByte(0xA1);//发送读指令
	I2CWaitAck();
	temp = I2CReceiveByte();
	I2CSendNotAck();
	I2CStop();
	
	return temp;
}