STM32硬件IIC读写EEPROM
前面一篇写了软件模拟IIC读写EEPROM。
本篇介绍硬件IIC读写EEPROM。平台是STM32F103+AT24C04N。SDA和SCL接5K上拉电阻到3.3v。
首先介绍AT24C04N的基本特性。512byte。支持1.8v~5.5v供电。支持5种读写模式。BYTE WRITE（字节写），PAGE WRITE（按页写）。RANDOM READ（随机读），SEQUENTIAL READ（顺序读）和CURRENT ADDRESS READ .具体时序参考数据手册。
我用的是I2C1接口。
宏定义如下：
#define EEPROM_Block_ADDRESS 0xA0 /* Device Address */
#define I2C1_SLAVE_ADDRESS7 0xA0
#define I2C_PageSize 16
#define I2C_BUF_LEN 256
#define EEPROM_I2C I2C1
#define EEPROM_I2C_CLK RCC_APB1Periph_I2C1
#define EEPROM_I2C_SCL_PIN GPIO_Pin_6 /* PB.6 */
#define EEPROM_I2C_SCL_GPIO_PORT GPIOB /* GPIOB */
#define EEPROM_I2C_SCL_GPIO_CLK RCC_APB2Periph_GPIOB
#define EEPROM_I2C_SDA_PIN GPIO_Pin_7 /* PB.7 */
#define EEPROM_I2C_SDA_GPIO_PORT GPIOB /* GPIOB */
#define EEPROM_I2C_SDA_GPIO_CLK RCC_APB2Periph_GPIOB
#define I2C_SPEED 200000
extern uint8_t I2C_Buf[I2C_BUF_LEN];
配置和功能函数如下：
/* Includes ------------------------------------------------------------------*/
#include
/* Private macro -------------------------------------------------------------*/
#define TIMEOUT 1000
/* Private variables ---------------------------------------------------------*/
uint8_t EEPROM_ADDRESS = EEPROM_Block_ADDRESS;
u32 I2C_Timeout =1000;
static void delay_ms(u32 t)
{
u16 i = 8000;
while(t--)
{
i = 8000;
while(i--);
}
}
static void delay_us(u32 d)
{
while(d--) ;
}
/**
* @brief Configure the used I/O ports pin
* @param None
* @retval : None
*/
void GPIO_Configuration(void)
{
#if 1
GPIO_InitTypeDef GPIO_InitStructure;
RCC_APB2PeriphClockCmd( EEPROM_I2C_SCL_GPIO_CLK | EEPROM_I2C_SDA_GPIO_CLK, ENABLE );
/* Configure I2C1 pins: SCL and SDA */
GPIO_InitStructure.GPIO_Pin = EEPROM_I2C_SCL_PIN | EEPROM_I2C_SDA_PIN;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_OD;
//GPIO_Init(EEPROM_I2C_SCL_GPIO_PORT | EEPROM_I2C_SDA_GPIO_PORT, &GPIO_InitStructure);
GPIO_Init(EEPROM_I2C_SCL_GPIO_PORT, &GPIO_InitStructure);
#endif
}
/**
* @brief I2C Configuration
* @param None
* @retval : None
*/
void I2C_Configuration(void)
{
#if 1
I2C_InitTypeDef I2C_InitStructure;
RCC_APB1PeriphClockCmd( EEPROM_I2C_CLK, ENABLE );
/* I2C configuration */
I2C_InitStructure.I2C_Mode = I2C_Mode_I2C;
I2C_InitStructure.I2C_DutyCycle = I2C_DutyCycle_2;
//I2C_InitStructure.I2C_OwnAddress1 = I2C1_SLAVE_ADDRESS7;
I2C_InitStructure.I2C_Ack = I2C_Ack_Enable;
I2C_InitStructure.I2C_AcknowledgedAddress = I2C_AcknowledgedAddress_7bit;
I2C_InitStructure.I2C_ClockSpeed = I2C_SPEED;
/* Apply I2C configuration after enabling it */
I2C_Init(EEPROM_I2C, &I2C_InitStructure);
/* I2C Peripheral Enable */
I2C_Cmd(EEPROM_I2C, ENABLE);
#endif
}
/**
* @brief Initializes peripherals used by the I2C EEPROM driver.
* @param None
* @retval : None
*/
void I2C_EE_Init()
{
/* GPIO configuration */
GPIO_Configuration();
/* I2C configuration */
I2C_Configuration();
/* depending on the EEPROM Address selected in the i2c_ee.h file */
/* Select the EEPROM Block0 to write on */
EEPROM_ADDRESS = EEPROM_Block_ADDRESS;
}
/**
* @brief Writes one byte to the I2C EEPROM.
* @param pBuffer : pointer to the buffer containing the data to be
* written to the EEPROM.
* @param WriteAddr : EEPROM's internal address to write to.
* @retval : None
*/
void I2C_EE_ByteWrite(uint8_t* pBuffer, uint8_t WriteAddr)
{
/* While the bus is busy */
while(I2C_GetFlagStatus(EEPROM_I2C, I2C_FLAG_BUSY));
/* Send STRAT condition */
I2C_GenerateSTART(EEPROM_I2C, ENABLE);
I2C_Timeout = TIMEOUT;
/* Test on EV5 and clear it */
while(!I2C_CheckEvent(EEPROM_I2C, I2C_EVENT_MASTER_MODE_SELECT))
{
if(I2C_Timeout-- == 0) break;
}
/* Send EEPROM address for write */
I2C_Send7bitAddress(EEPROM_I2C, EEPROM_ADDRESS, I2C_Direction_Transmitter);
I2C_Timeout = TIMEOUT;
/* Test on EV6 and clear it */
while(!I2C_CheckEvent(EEPROM_I2C, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED))
{
if(I2C_Timeout-- == 0) break;
}
/* Send the EEPROM's internal address to write to */
I2C_SendData(EEPROM_I2C, WriteAddr);
I2C_Timeout = TIMEOUT;
/* Test on EV8 and clear it */
while(!I2C_CheckEvent(EEPROM_I2C, I2C_EVENT_MASTER_BYTE_TRANSMITTED))
{
if(I2C_Timeout-- == 0) break;
}
/* Send the byte to be written */
I2C_SendData(EEPROM_I2C, *pBuffer);
I2C_Timeout = TIMEOUT;
/* Test on EV8 and clear it */
while(!I2C_CheckEvent(EEPROM_I2C, I2C_EVENT_MASTER_BYTE_TRANSMITTED))
{
if(I2C_Timeout-- == 0) break;
}
/* Send STOP condition */
I2C_GenerateSTOP(EEPROM_I2C, ENABLE);
/* 延时不得小于5ms write cycle time*/
delay_ms(15);
}
/**
* @brief Writes more than one byte to the EEPROM with a single WRITE
* cycle. The number of byte can't exceed the EEPROM page size.
* @param pBuffer : pointer to the buffer containing the data to be
* written to the EEPROM.
* @param WriteAddr : EEPROM's internal address to write to.
* @param NumByteToWrite : number of bytes to write to the EEPROM.
* @retval : None
*/
void I2C_EE_PageWrite(uint8_t* pBuffer, uint8_t WriteAddr)
{
#if 1
uint8_t NumByteToWrite;
NumByteToWrite = I2C_PageSize;
/* While the bus is busy */
while(I2C_GetFlagStatus(EEPROM_I2C, I2C_FLAG_BUSY));
/* Send START condition */
I2C_GenerateSTART(EEPROM_I2C, ENABLE);
/* Test on EV5 and clear it */
while(!I2C_CheckEvent(EEPROM_I2C, I2C_EVENT_MASTER_MODE_SELECT));
/* Send EEPROM address for write */
I2C_Send7bitAddress(EEPROM_I2C, EEPROM_ADDRESS, I2C_Direction_Transmitter);
/* Test on EV6 and clear it */
while(!I2C_CheckEvent(EEPROM_I2C, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED));
/* Send the EEPROM's internal address to write to */
I2C_SendData(EEPROM_I2C, WriteAddr);
/* Test on EV8 and clear it */
while(! I2C_CheckEvent(EEPROM_I2C, I2C_EVENT_MASTER_BYTE_TRANSMITTED));
/* While there is data to be written */
while(NumByteToWrite--)
{
/* Send the current byte */
I2C_SendData(EEPROM_I2C, *pBuffer);
/* Point to the next byte to be written */
pBuffer++;
/* Test on EV8 and clear it */
while (!I2C_CheckEvent(EEPROM_I2C, I2C_EVENT_MASTER_BYTE_TRANSMITTED));
}
/* Send STOP condition */
I2C_GenerateSTOP(EEPROM_I2C, ENABLE);
/* 延时不得小于5ms write cycle time*/
delay_ms(20);
#endif
}
void I2C_EE_RandomrRead(uint8_t* pBuffer, uint8_t ReadAddr)
{
/* While the bus is busy */
while(I2C_GetFlagStatus(EEPROM_I2C, I2C_FLAG_BUSY));
/* step 1 Send START condition */
I2C_GenerateSTART(EEPROM_I2C, ENABLE);
I2C_Timeout = TIMEOUT;
/* Test on EV5 and clear it */
while(!I2C_CheckEvent(EEPROM_I2C, I2C_EVENT_MASTER_MODE_SELECT))
{
if(I2C_Timeout-- == 0) break;
}
/* step 2 Send EEPROM address for write */
I2C_Send7bitAddress(EEPROM_I2C, EEPROM_ADDRESS, I2C_Direction_Transmitter);
I2C_Timeout = TIMEOUT;
/* Test on EV6 and clear it */
while(!I2C_CheckEvent(EEPROM_I2C, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED))
{
if(I2C_Timeout-- == 0) break;
}
/* Clear EV6 by setting again the PE bit */
I2C_Cmd(EEPROM_I2C, ENABLE);
//printf("\r\nstep 3:IIC reg addr \r\n");
/* step 3 Send the EEPROM's internal address to write to */
I2C_SendData(EEPROM_I2C, ReadAddr);
I2C_Timeout = TIMEOUT;
/* Test on EV8 and clear it */
while(!I2C_CheckEvent(EEPROM_I2C, I2C_EVENT_MASTER_BYTE_TRANSMITTED))
{
if(I2C_Timeout-- == 0) break;
}
/* step 4 Send STRAT condition a second time */
I2C_GenerateSTART(EEPROM_I2C, ENABLE);
I2C_Timeout = TIMEOUT;
/* Test on EV5 and clear it */
while(!I2C_CheckEvent(EEPROM_I2C, I2C_EVENT_MASTER_MODE_SELECT))
{
if(I2C_Timeout-- == 0) break;
}
/*step 5 Send EEPROM address for read */
I2C_Send7bitAddress(EEPROM_I2C, EEPROM_ADDRESS, I2C_Direction_Receiver);
I2C_Timeout = TIMEOUT;
/* Test on EV6 and clear it */
while(!I2C_CheckEvent(EEPROM_I2C, I2C_EVENT_MASTER_RECEIVER_MODE_SELECTED))
{
if(I2C_Timeout-- == 0) break;
}
/*step 6 Disable Acknowledgement */
I2C_AcknowledgeConfig(EEPROM_I2C, DISABLE);
/*step 7 Send STOP Condition ,如果不在此处发stop信号， 而在接收数据后，会多收一个字节*/
I2C_GenerateSTOP(EEPROM_I2C, ENABLE);
I2C_Timeout = TIMEOUT;
while(I2C_GetFlagStatus(EEPROM_I2C,I2C_FLAG_RXNE) == RESET)
{
if(I2C_Timeout-- == 0) break;
}
*pBuffer = I2C_ReceiveData(EEPROM_I2C);
/*step 7 Send STOP Condition */
//I2C_GenerateSTOP(EEPROM_I2C, ENABLE);
//printf("\r\nIIC rec data 0x%x\r\n",*pBuffer);
}
uint8_t I2C_EE_CurrentRead(void)
{
uint8_t recdata = 0x0;
#if 1
/* While the bus is busy */
while(I2C_GetFlagStatus(EEPROM_I2C, I2C_FLAG_BUSY));
/* step 4 Send STRAT condition a second time */
I2C_GenerateSTART(EEPROM_I2C, ENABLE);
I2C_Timeout = TIMEOUT;
/* Test on EV5 and clear it */
while(!I2C_CheckEvent(EEPROM_I2C, I2C_EVENT_MASTER_MODE_SELECT))
{
if(I2C_Timeout-- == 0) break;
}
/*step 5 Send EEPROM address for read */
I2C_Send7bitAddress(EEPROM_I2C, EEPROM_ADDRESS, I2C_Direction_Receiver);
I2C_Timeout = TIMEOUT;
/* Test on EV6 and clear it */
while(!I2C_CheckEvent(EEPROM_I2C, I2C_EVENT_MASTER_RECEIVER_MODE_SELECTED))
{
if(I2C_Timeout-- == 0) break;
}
/*step 6 Disable Acknowledgement */
I2C_AcknowledgeConfig(EEPROM_I2C, DISABLE);
/*step 7 Send STOP Condition ,如果不在此处发stop信号， 而在接收数据后，会多收一个字节*/
I2C_GenerateSTOP(EEPROM_I2C, ENABLE);
I2C_Timeout = TIMEOUT;
while(I2C_GetFlagStatus(EEPROM_I2C,I2C_FLAG_RXNE) == RESET)
{
if(I2C_Timeout-- == 0) break;
}
recdata = I2C_ReceiveData(EEPROM_I2C);
/*step 7 Send STOP Condition */
//I2C_GenerateSTOP(EEPROM_I2C, ENABLE);
#endif
return recdata;
}
代码参考了普中科技的ARM板子例程。板子例程里有很多bug不太好用。如果有源码大家可以对比研究。我实现了随机读，顺序读，按字节写，按页写等4种标准操作。请注意注释部分，这些代码都经过平台验证，可以直接使用，因为我的板子A0~A2都接到GND上了，所以，我的代码支持前256字节操作。
实际波形如下：
作者：yilizhihu
