本文主要是介绍STM32：I2C接口读写EEPROM(AT24C02)试验例程，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！
硬件平台：stm32f10xZET6开发环境：keil MDK uVisionv4.10
开发语言：C、ST_lib_3.5固件库
EEPROM：电可擦可编程只读存储器。
【stm32f10xZET6开发板的I2C外设物理层特点】
(1)两条串行总线：一条双向数据线(SDA)，一条时钟线(SCL)；
(2)从设备地址唯一；
(3)支持总线仲裁；
(4)三种速率传输模式：
标准模式100kbit/s
快速模式400kbit/s
高速模式3.4Mbit/s (目前大多I2C设备尚不支持高速模式)
(5)片上的滤波器可以滤去总线数据线上的毛刺波保证数据完整；
(6)连接到相同总线的IC数量受到总线的最大电容400pF限制；
【I2C接口特性】
(1) STM32 中和大容量型号芯片均有多达 2 个I2C总线接口；
(2) 能够工作于多主机或多从机模式，主从均可收发；
(3) 支持标准模式 100Kbit/s 和快速模式 400Kbit/s，不支持高
速模式；
(4) 支持 7 位或 10 位从设备地址寻址；
(5) 内置了硬件 CRC 发生器/ 校验器；
(6) I2C 的接收和发送都可以使用 DMA 操作；
(7) 支持系统管理总线(SMBus)总线 2.0 版；
typedef struct
{
uint32_t I2C_ClockSpeed; /*!< 指定时钟总线速率，100/400kHz */
uint16_t I2C_Mode; /*!< 指定为I2C通信模式 */
uint16_t I2C_DutyCycle; /*!< 指定I2C快速模式 */
uint16_t I2C_OwnAddress1; /*!< 指定从设备自身地址，7/10bit(地址0x0A对应宏) */
uint16_t I2C_Ack; /*!< 使能或禁止ack */
uint16_t I2C_AcknowledgedAddress; /*!< 指定7/10bit从设备地址下的ack */
} I2C_InitTypeDef;
在 stm32 如何建立与 EEPROM 的通讯步骤：
(1) 配置 I/O 端口，确定并配置 I2C 的模式，使能 GPIO 和 I2C
时钟。
(2) 写：
1) 检测 SDA 是否空闲；
2) 按 I2C 协议发出起始信号；
3) 发出 7 位器件地址和写模式；
4) 要写入的存储区首地址；
5) 用页写入方式或字节写入方式写入数据；
6) 发送 I2C 通讯结束讯信号
每个操作之后要检测“事件”确定是否成功。写完后检测 EEPROM 是否进
入 standby 状态。
(3) 读：
1) 检测 SDA 是否空闲；
2) 按 I2C 协议发出起始讯号；
3) 发出 7 位器件地址和写模式（伪写）；
4) 发出要读取的存储区首地址；
5) 重发起始讯号；第 260 页 共 729 页
6) 发出 7 位器件地址和读模式；
7) 接收数据；
类似写操作，每个操作之后要检测“事件”确定是否成功。
I2C_GenerateSTART(); // 产生 I2C 的通讯起始信号 S
I2C_Send7bitAddress(); // 发送7位从设备地址
I2C_SendData(); // 发送一个数据字节(8bit)
I2C_GenerateSTOP(); // 产生 I2C 的通讯停止信号 P
I2C_CheckEvent (); // I2C 传输时的事件监测
/* 代码演示 - mian.c */
/********************************************************************************* @file main.c* @author fire* @version V1.0* @date 2013-xx-xx* @brief I2C EEPROM(AT24C02)测试，测试信息通过USART1打印在电脑的超级终端*******************************************************************************/#include "stm32f10x.h"
#include "bsp_usart1.h"
#include "bsP_i2c_ee.h"
#include "bsP_led.h"
#include <string.h>#define EEP_Firstpage 0x00
u8 I2c_Buf_Write[256];
u8 I2c_Buf_Read[256];
void I2C_Test(void);/*** @brief 主函数* @param 无* @retval 无*/
int main(void)
{ /* 串口1初始化 */USART1_Config();printf("\r\n 这是一个I2C外设(AT24C02)读写测试例程 \r\n");//LED_GPIO_Config();/* I2C 外设初(AT24C02)始化 */I2C_EE_Init();printf("\r\n 这是一个I2C外设(AT24C02)读写测试例程 \r\n"); I2C_Test();while (1){ }
}/*** @brief I2C(AT24C02)读写测试* @param 无* @retval 无*/
void I2C_Test(void)
{u16 i;printf("写入的数据\n\r");for ( i=0; i<=255; i++ ) // 填充缓冲{ I2c_Buf_Write[i] = i;printf("0x%02X ", I2c_Buf_Write[i]);if(i%16 == 15) printf("\n\r"); }//将I2c_Buf_Write中顺序递增的数据写入EERPOM中 //LED1(ON);I2C_EE_BufferWrite (I2c_Buf_Write, EEP_Firstpage, 256);//LED1(OFF); printf("\n\r写成功\n\r");printf("\n\r读出的数据\n\r");//将EEPROM读出数据顺序保持到I2c_Buf_Read中//LED2(ON); I2C_EE_BufferRead(I2c_Buf_Read, EEP_Firstpage, 256); //LED2(OFF);//将I2c_Buf_Read中的数据通过串口打印for (i=0; i<256; i++){ if(I2c_Buf_Read[i] != I2c_Buf_Write[i]){printf("0x%02X ", I2c_Buf_Read[i]);printf("错误:I2C EEPROM写入与读出的数据不一致\n\r");return;}printf("0x%02X ", I2c_Buf_Read[i]);if(i%16 == 15) printf("\n\r");}printf("I2C(AT24C02)读写测试成功\n\r");
}/* 代码演示 - bsp_i2c_ee模块 */
#ifndef __I2C_EE_H
#define __I2C_EE_H#include "stm32f10x.h"/* * AT24C02 2kb = 2048bit = 2048/8 B = 256 B* 32 pages of 8 bytes each** Device Address* 1 0 1 0 A2 A1 A0 R/W* 1 0 1 0 0 0 0 0 = 0XA0* 1 0 1 0 0 0 0 1 = 0XA1 *//* EEPROM Addresses defines */
#define EEPROM_Block0_ADDRESS 0xA0 /* E2 = 0 */
//#define EEPROM_Block1_ADDRESS 0xA2 /* E2 = 0 */
//#define EEPROM_Block2_ADDRESS 0xA4 /* E2 = 0 */
//#define EEPROM_Block3_ADDRESS 0xA6 /* E2 = 0 */void I2C_EE_Init(void);
void I2C_EE_BufferWrite(u8* pBuffer, u8 WriteAddr, u16 NumByteToWrite);
void I2C_EE_ByteWrite(u8* pBuffer, u8 WriteAddr);
void I2C_EE_PageWrite(u8* pBuffer, u8 WriteAddr, u8 NumByteToWrite);
void I2C_EE_BufferRead(u8* pBuffer, u8 ReadAddr, u16 NumByteToRead);
void I2C_EE_WaitEepromStandbyState(void);#endif /* __I2C_EE_H *///--------------------------------------------------------
/********************************************************************************* @file bsp_i2c_ee.c* @author STMicroelectronics* @version V1.0* @date 2013-xx-xx* @brief i2c EEPROM(AT24C02)应用函数bsp*******************************************************************************/ #include "bsp_i2c_ee.h"/* STM32 I2C 快速模式 */
#define I2C_Speed 400000/* 这个地址只要与STM32外挂的I2C器件地址不一样即可 */
#define I2C1_OWN_ADDRESS7 0X0A /* AT24C01/02每页有8个字节 */
#define I2C_PageSize 8/* AT24C04/08A/16A每页有16个字节 */
//#define I2C_PageSize 16 uint16_t EEPROM_ADDRESS;/*** @brief I2C1 I/O配置* @param 无* @retval 无*/
static void I2C_GPIO_Config(void)
{GPIO_InitTypeDef GPIO_InitStructure; /* 使能与 I2C1 有关的时钟 */RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB,ENABLE);RCC_APB1PeriphClockCmd(RCC_APB1Periph_I2C1,ENABLE); /* PB6-I2C1_SCL、PB7-I2C1_SDA*/GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_7;GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_OD; // 开漏输出GPIO_Init(GPIOB, &GPIO_InitStructure);
}/*** @brief I2C 工作模式配置* @param 无* @retval 无*/
static void I2C_Mode_Configu(void)
{I2C_InitTypeDef I2C_InitStructure; /* I2C 配置 */I2C_InitStructure.I2C_Mode = I2C_Mode_I2C;/* 高电平数据稳定，低电平数据变化 SCL 时钟线的占空比 */I2C_InitStructure.I2C_DutyCycle = I2C_DutyCycle_2;I2C_InitStructure.I2C_OwnAddress1 = I2C1_OWN_ADDRESS7; I2C_InitStructure.I2C_Ack = I2C_Ack_Enable ;/* I2C的寻址模式 */I2C_InitStructure.I2C_AcknowledgedAddress = I2C_AcknowledgedAddress_7bit;/* 通信速率 */I2C_InitStructure.I2C_ClockSpeed = I2C_Speed;/* I2C1 初始化 */I2C_Init(I2C1, &I2C_InitStructure);/* 使能 I2C1 */I2C_Cmd(I2C1, ENABLE);
}/*** @brief I2C 外设(EEPROM)初始化* @param 无* @retval 无*/
void I2C_EE_Init(void)
{I2C_GPIO_Config(); I2C_Mode_Configu();/* 根据头文件i2c_ee.h中的定义来选择EEPROM要写入的地址 */
#ifdef EEPROM_Block0_ADDRESS/* 选择 EEPROM Block0 来写入 */EEPROM_ADDRESS = EEPROM_Block0_ADDRESS;
#endif#ifdef EEPROM_Block1_ADDRESS /* 选择 EEPROM Block1 来写入 */EEPROM_ADDRESS = EEPROM_Block1_ADDRESS;
#endif#ifdef EEPROM_Block2_ADDRESS /* 选择 EEPROM Block2 来写入 */EEPROM_ADDRESS = EEPROM_Block2_ADDRESS;
#endif#ifdef EEPROM_Block3_ADDRESS /* 选择 EEPROM Block3 来写入 */EEPROM_ADDRESS = EEPROM_Block3_ADDRESS;
#endif
}/*** @brief 将缓冲区中的数据写到I2C EEPROM中* @param * @arg pBuffer:缓冲区指针* @arg WriteAddr:写地址* @arg NumByteToWrite:写的字节数* @retval 无*/
void I2C_EE_BufferWrite(u8* pBuffer, u8 WriteAddr, u16 NumByteToWrite)
{u8 NumOfPage = 0, NumOfSingle = 0, Addr = 0, count = 0;Addr = WriteAddr % I2C_PageSize; // addr = 8bit % 8count = I2C_PageSize - Addr; // 8 - addrNumOfPage = NumByteToWrite / I2C_PageSize;NumOfSingle = NumByteToWrite % I2C_PageSize;/* If WriteAddr is I2C_PageSize aligned */if(Addr == 0) {/* If NumByteToWrite < I2C_PageSize */if(NumOfPage == 0) {I2C_EE_PageWrite(pBuffer, WriteAddr, NumOfSingle);I2C_EE_WaitEepromStandbyState();}/* If NumByteToWrite > I2C_PageSize */else {while(NumOfPage--){I2C_EE_PageWrite(pBuffer, WriteAddr, I2C_PageSize); I2C_EE_WaitEepromStandbyState();WriteAddr += I2C_PageSize;pBuffer += I2C_PageSize;}if(NumOfSingle!=0){I2C_EE_PageWrite(pBuffer, WriteAddr, NumOfSingle);I2C_EE_WaitEepromStandbyState();}}}/* If WriteAddr is not I2C_PageSize aligned */else {/* If NumByteToWrite < I2C_PageSize */if(NumOfPage== 0) {I2C_EE_PageWrite(pBuffer, WriteAddr, NumOfSingle);I2C_EE_WaitEepromStandbyState();}/* If NumByteToWrite > I2C_PageSize */else{NumByteToWrite -= count;NumOfPage = NumByteToWrite / I2C_PageSize;NumOfSingle = NumByteToWrite % I2C_PageSize; if(count != 0){ I2C_EE_PageWrite(pBuffer, WriteAddr, count);I2C_EE_WaitEepromStandbyState();WriteAddr += count;pBuffer += count;} while(NumOfPage--){I2C_EE_PageWrite(pBuffer, WriteAddr, I2C_PageSize);I2C_EE_WaitEepromStandbyState();WriteAddr += I2C_PageSize;pBuffer += I2C_PageSize; }if(NumOfSingle != 0){I2C_EE_PageWrite(pBuffer, WriteAddr, NumOfSingle); I2C_EE_WaitEepromStandbyState();}}}
}/*** @brief 写一个字节到I2C EEPROM中* @param * @arg pBuffer:缓冲区指针* @arg WriteAddr:写地址 * @retval 无*/
void I2C_EE_ByteWrite(u8* pBuffer, u8 WriteAddr)
{/* Send STRAT condition */I2C_GenerateSTART(I2C1, ENABLE);/* Test on EV5 and clear it */while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_MODE_SELECT)); /* Send EEPROM address for write */I2C_Send7bitAddress(I2C1, EEPROM_ADDRESS, I2C_Direction_Transmitter);/* Test on EV6 and clear it */while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED));/* Send the EEPROM's internal address to write to */I2C_SendData(I2C1, WriteAddr);/* Test on EV8 and clear it */while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_TRANSMITTED));/* Send the byte to be written */I2C_SendData(I2C1, *pBuffer); /* Test on EV8 and clear it */while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_TRANSMITTED));/* Send STOP condition */I2C_GenerateSTOP(I2C1, ENABLE);
}/*** @brief 在EEPROM的一个写循环中可以写多个字节，但一次写入的字节数* 不能超过EEPROM页的大小，AT24C02每页有8个字节* @param * @arg pBuffer:缓冲区指针* @arg WriteAddr:写地址* @arg NumByteToWrite:写的字节数* @retval 无*/
void I2C_EE_PageWrite(u8* pBuffer, u8 WriteAddr, u8 NumByteToWrite)
{while(I2C_GetFlagStatus(I2C1, I2C_FLAG_BUSY)); // Added by Najoua 27/08/2008/* 发送start信号 */I2C_GenerateSTART(I2C1, ENABLE);/* Test on EV5 and clear it */while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_MODE_SELECT)); /* Send EEPROM address for write */I2C_Send7bitAddress(I2C1, EEPROM_ADDRESS, I2C_Direction_Transmitter);/* Test on EV6 and clear it */while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED)); /* Send the EEPROM's internal address to write to */ I2C_SendData(I2C1, WriteAddr); /* Test on EV8 and clear it */while(! I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_TRANSMITTED));/* While there is data to be written */while(NumByteToWrite--) {/* Send the current byte */I2C_SendData(I2C1, *pBuffer); /* Point to the next byte to be written */pBuffer++; /* Test on EV8 and clear it */while (!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_TRANSMITTED));}/* Send STOP condition */I2C_GenerateSTOP(I2C1, ENABLE);
}/*** @brief 从EEPROM里面读取一块数据 * @param * @arg pBuffer:存放从EEPROM读取的数据的缓冲区指针* @arg WriteAddr:接收数据的EEPROM的地址* @arg NumByteToWrite:要从EEPROM读取的字节数* @retval 无*/
void I2C_EE_BufferRead(u8* pBuffer, u8 ReadAddr, u16 NumByteToRead)
{ //*((u8 *)0x4001080c) |=0x80; while(I2C_GetFlagStatus(I2C1, I2C_FLAG_BUSY)); // Added by Najoua 27/08/2008 /* Send START condition */I2C_GenerateSTART(I2C1, ENABLE);//*((u8 *)0x4001080c) &=~0x80;/* Test on EV5 and clear it */while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_MODE_SELECT));/* Send EEPROM address for write */I2C_Send7bitAddress(I2C1, EEPROM_ADDRESS, I2C_Direction_Transmitter);/* Test on EV6 and clear it */while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED));/* Clear EV6 by setting again the PE bit */I2C_Cmd(I2C1, ENABLE);/* Send the EEPROM's internal address to write to */I2C_SendData(I2C1, ReadAddr); /* Test on EV8 and clear it */while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_TRANSMITTED));/* Send STRAT condition a second time */ I2C_GenerateSTART(I2C1, ENABLE);/* Test on EV5 and clear it */while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_MODE_SELECT));/* Send EEPROM address for read */I2C_Send7bitAddress(I2C1, EEPROM_ADDRESS, I2C_Direction_Receiver);/* Test on EV6 and clear it */while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_RECEIVER_MODE_SELECTED));/* While there is data to be read */while(NumByteToRead) {if(NumByteToRead == 1){/* Disable Acknowledgement */I2C_AcknowledgeConfig(I2C1, DISABLE);/* Send STOP Condition */I2C_GenerateSTOP(I2C1, ENABLE);}/* Test on EV7 and clear it */if(I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_RECEIVED)) { /* Read a byte from the EEPROM */*pBuffer = I2C_ReceiveData(I2C1);/* Point to the next location where the byte read will be saved */pBuffer++; /* Decrement the read bytes counter */NumByteToRead--; } }/* Enable Acknowledgement to be ready for another reception */I2C_AcknowledgeConfig(I2C1, ENABLE);
}/*** @brief Wait for EEPROM Standby state * @param 无* @retval 无*/
void I2C_EE_WaitEepromStandbyState(void)
{vu16 SR1_Tmp = 0;do{/* Send START condition */I2C_GenerateSTART(I2C1, ENABLE);/* Read I2C1 SR1 register */SR1_Tmp = I2C_ReadRegister(I2C1, I2C_Register_SR1);/* Send EEPROM address for write */I2C_Send7bitAddress(I2C1, EEPROM_ADDRESS, I2C_Direction_Transmitter);}while(!(I2C_ReadRegister(I2C1, I2C_Register_SR1) & 0x0002));/* Clear AF flag */I2C_ClearFlag(I2C1, I2C_FLAG_AF);/* STOP condition */ I2C_GenerateSTOP(I2C1, ENABLE);
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