小松的STM32教程（13）—— 驱动外部内存24C02

预备

学习目标

概述

24cxx.c

#include "24cxx.h" 
#include "delay.h"
#include "delay.h"


void IIC_Init(void)
{
	GPIO_InitTypeDef GPIO_InitStructure;
	//RCC->APB2ENR|=1<<4;//��ʹ������IO PORTCʱ��
	RCC_APB2PeriphClockCmd(	RCC_APB2Periph_GPIOC, ENABLE );

	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_12|GPIO_Pin_11;
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP ;   //�������
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
	GPIO_Init(GPIOC, &GPIO_InitStructure);

	IIC_SCL=1;
	IIC_SDA=1;

}
//����IIC��ʼ�ź�
void IIC_Start(void)
{
	SDA_OUT();     //sda�����
	IIC_SDA=1;
	IIC_SCL=1;
	delay_us(4);
 	IIC_SDA=0;//START:when CLK is high,DATA change form high to low
	delay_us(4);
	IIC_SCL=0;//ǯסI2C���ߣ�׼�����ͻ��������
}
//����IICֹͣ�ź�
void IIC_Stop(void)
{
	SDA_OUT();//sda�����
	IIC_SCL=0;
	IIC_SDA=0;//STOP:when CLK is high DATA change form low to high
 	delay_us(4);
	IIC_SCL=1;
	IIC_SDA=1;//����I2C���߽����ź�
	delay_us(4);
}
//�ȴ�Ӧ���źŵ���
//����ֵ��1������Ӧ��ʧ��
//        0������Ӧ��ɹ�
u8 IIC_Wait_Ack(void)
{
	u8 ucErrTime=0;
	SDA_IN();      //SDA��������
	IIC_SDA=1;delay_us(1);
	IIC_SCL=1;delay_us(1);
	while(READ_SDA)
	{
		ucErrTime++;
		if(ucErrTime>250)
		{
			IIC_Stop();
			return 1;
		}
	}
	IIC_SCL=0;//ʱ�����0
	return 0;
}
//����ACKӦ��
void IIC_Ack(void)
{
	IIC_SCL=0;
	SDA_OUT();
	IIC_SDA=0;
	delay_us(2);
	IIC_SCL=1;
	delay_us(2);
	IIC_SCL=0;
}
//������ACKӦ��
void IIC_NAck(void)
{
	IIC_SCL=0;
	SDA_OUT();
	IIC_SDA=1;
	delay_us(2);
	IIC_SCL=1;
	delay_us(2);
	IIC_SCL=0;
}
//IIC����һ���ֽ�
//���شӻ�����Ӧ��
//1����Ӧ��
//0����Ӧ��
void IIC_Send_Byte(u8 txd)
{
    u8 t;
	SDA_OUT();
    IIC_SCL=0;//����ʱ�ӿ�ʼ���ݴ���
    for(t=0;t<8;t++)
    {
        IIC_SDA=(txd&0x80)>>7;
        txd<<=1;
		delay_us(2);   //��TEA5767��������ʱ���DZ����
		IIC_SCL=1;
		delay_us(2);
		IIC_SCL=0;
		delay_us(2);
    }
}
//��1���ֽڣ�ack=1ʱ������ACK��ack=0������nACK
u8 IIC_Read_Byte(unsigned char ack)
{
	unsigned char i,receive=0;
	SDA_IN();//SDA��������
    for(i=0;i<8;i++ )
	{
        IIC_SCL=0;
        delay_us(2);
		IIC_SCL=1;
        receive<<=1;
        if(READ_SDA)receive++;
		delay_us(1);
    }
    if (!ack)
        IIC_NAck();//����nACK
    else
        IIC_Ack(); //����ACK
    return receive;
}

void AT24CXX_Init(void)
{
	IIC_Init();
}

u8 AT24CXX_ReadOneByte(u16 ReadAddr)
{				  
	u8 temp=0;		  	    																 
    IIC_Start();  
	if(EE_TYPE>AT24C16)
	{
		IIC_Send_Byte(0XA0);	   //�������
		IIC_Wait_Ack();
		IIC_Send_Byte(ReadAddr>>8);//���͸ߵ�ַ
		IIC_Wait_Ack();		 
	}else IIC_Send_Byte(0XA0+((ReadAddr/256)<<1));   //����������ַ0XA0,д���� 	 

	IIC_Wait_Ack(); 
    IIC_Send_Byte(ReadAddr%256);   //���͵͵�ַ
	IIC_Wait_Ack();	    
	IIC_Start();  	 	   
	IIC_Send_Byte(0XA1);           //�������ģʽ			   
	IIC_Wait_Ack();	 
    temp=IIC_Read_Byte(0);		   
    IIC_Stop();//����һ��ֹͣ����	    
	return temp;
}

void AT24CXX_WriteOneByte(u16 WriteAddr,u8 DataToWrite)
{				   	  	    																 
    IIC_Start();  
	if(EE_TYPE>AT24C16)
	{
		IIC_Send_Byte(0XA0);	    //�������
		IIC_Wait_Ack();
		IIC_Send_Byte(WriteAddr>>8);//���͸ߵ�ַ
 	}else
	{
		IIC_Send_Byte(0XA0+((WriteAddr/256)<<1));   //����������ַ0XA0,д���� 
	}	 
	IIC_Wait_Ack();	   
    IIC_Send_Byte(WriteAddr%256);   //���͵͵�ַ
	IIC_Wait_Ack(); 	 										  		   
	IIC_Send_Byte(DataToWrite);     //�����ֽ�							   
	IIC_Wait_Ack();  		    	   
    IIC_Stop();//����һ��ֹͣ���� 
	delay_ms(10);	 
}

void AT24CXX_WriteLenByte(u16 WriteAddr,u32 DataToWrite,u8 Len)
{  	
	u8 t;
	for(t=0;t<Len;t++)
	{
		AT24CXX_WriteOneByte(WriteAddr+t,(DataToWrite>>(8*t))&0xff);
	}												    
}


u32 AT24CXX_ReadLenByte(u16 ReadAddr,u8 Len)
{  	
	u8 t;
	u32 temp=0;
	for(t=0;t<Len;t++)
	{
		temp<<=8;
		temp+=AT24CXX_ReadOneByte(ReadAddr+Len-t-1); 	 				   
	}
	return temp;												    
}

u8 AT24CXX_Check(void)
{
	u8 temp;
	temp=AT24CXX_ReadOneByte(255);//����ÿ�ο�����дAT24CXX			   
	if(temp==0X55)return 0;		   
	else//�ų���һ�γ�ʼ�������
	{
		AT24CXX_WriteOneByte(255,0X55);
	    temp=AT24CXX_ReadOneByte(255);	  
		if(temp==0X55)return 0;
	}
	return 1;											  
}


void AT24CXX_Read(u16 ReadAddr,u8 *pBuffer,u16 NumToRead)
{
	while(NumToRead)
	{
		*pBuffer++=AT24CXX_ReadOneByte(ReadAddr++);	
		NumToRead--;
	}
}  

void AT24CXX_Write(u16 WriteAddr,u8 *pBuffer,u16 NumToWrite)
{
	while(NumToWrite--)
	{
		AT24CXX_WriteOneByte(WriteAddr,*pBuffer);
		WriteAddr++;
		pBuffer++;
	}
}

24cxx.h

#ifndef __24CXX_H
#define __24CXX_H
#include "myiic.h"   
#include "sys.h"

#define AT24C01		127
#define AT24C02		255
#define AT24C04		511
#define AT24C08		1023
#define AT24C16		2047
#define AT24C32		4095
#define AT24C64	    8191
#define AT24C128	16383
#define AT24C256	32767

#define SDA_IN()  {GPIOC->CRH&=0XFFFF0FFF;GPIOC->CRH|=8<<12;}
#define SDA_OUT() {GPIOC->CRH&=0XFFFF0FFF;GPIOC->CRH|=3<<12;}

#define IIC_SCL    PCout(12) //SCL
#define IIC_SDA    PCout(11) //SDA
#define READ_SDA   PCin(11)  //����SDA
#define EE_TYPE AT24C02

void IIC_Init(void);                //��ʼ��IIC��IO��
void IIC_Start(void);				//����IIC��ʼ�ź�
void IIC_Stop(void);	  			//����IICֹͣ�ź�
void IIC_Send_Byte(u8 txd);			//IIC����һ���ֽ�
u8 IIC_Read_Byte(unsigned char ack);//IIC��ȡһ���ֽ�
u8 IIC_Wait_Ack(void); 				//IIC�ȴ�ACK�ź�
void IIC_Ack(void);					//IIC����ACK�ź�
void IIC_NAck(void);				//IIC������ACK�ź�
void IIC_Write_One_Byte(u8 daddr,u8 addr,u8 data);
u8 IIC_Read_One_Byte(u8 daddr,u8 addr);

u8 AT24CXX_ReadOneByte(u16 ReadAddr);							//ָ����ַ��ȡһ���ֽ�
void AT24CXX_WriteOneByte(u16 WriteAddr,u8 DataToWrite);		//ָ����ַд��һ���ֽ�
void AT24CXX_WriteLenByte(u16 WriteAddr,u32 DataToWrite,u8 Len);//ָ����ַ��ʼд��ָ�����ȵ�����
u32 AT24CXX_ReadLenByte(u16 ReadAddr,u8 Len);					//ָ����ַ��ʼ��ȡָ����������
void AT24CXX_Write(u16 WriteAddr,u8 *pBuffer,u16 NumToWrite);	//��ָ����ַ��ʼд��ָ�����ȵ�����
void AT24CXX_Read(u16 ReadAddr,u8 *pBuffer,u16 NumToRead);   	//��ָ����ַ��ʼ����ָ�����ȵ�����
u8 AT24CXX_Check(void);  //�������
void AT24CXX_Init(void); //��ʼ��IIC

#endif

主函数调用

#include "delay.h"
#include "sys.h"
#include "oled.h"
#include "key.h"
#include "24cxx.h"

const u8 TEXT_Buffer[]="Kafen Wong EDIL";
#define SIZE sizeof(TEXT_Buffer)

 int main(void)
 {
	delay_init();
	OLED_Init();//显示屏初始化
	u8 datatemp[SIZE];
	NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);// 设置中断优先级分组2
	KEY_Init();				//按键初始化
	AT24CXX_Init();			//芯片初始化

 	while(AT24CXX_Check())//检测不到24c02
	{
 		OLED_Refresh();
		OLED_ShowString(0,0,"CANT OPEN",16,1);
	}

 	OLED_ShowString(0,0,"OK!",16,1);
 	static int ii=0;

	while(1)
	{
		OLED_Refresh();
		if(KEY_Scan())//WK_UP 按下,写入24C02
		{
			ii++;
			if(ii%2){
				OLED_Clear();
				OLED_Refresh();
				OLED_ShowString(0,0,"Start Write",16,1);
				AT24CXX_Write(0,(u8*)TEXT_Buffer,SIZE);
				OLED_ShowString(0,16,"Finished",16,1);
			}
			else{
				OLED_Clear();
				OLED_Refresh();
				OLED_ShowString(0,0,"Start Read",16,1);
				AT24CXX_Read(0,datatemp,SIZE);
				OLED_ShowString(0,16,"Data is",16,1);
				OLED_ShowString(0,32,datatemp,16,1);
			}
		}
	}
}

作业

1. 尝试把库中IIC的部分独立出来，并且将OLED库的IIC函数删去，使用独立出来的IIC库