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I2C EEPROM Transmittiong and Receiving

Question asked by hosS on Mar 21, 2013
Latest reply on Mar 27, 2013 by hosS
Hi,

I am trying to send Datas to a 24C128 EEPROM via I2C interface of an STM32F4 Discovery. 
The problem is that I am not receiving the same value I am writing into the EEPROM. I am trying to write 0x05 into 0x00 address but when I run the program I get 0xA1 instead. And if I debug the code step by step I get 0xFF on reception. Couldnt find out what's wrong. Here is my code.

#include "stm32F4xx.h"
#include "stm32f4xx_gpio.h"
#include "stm32f4xx_i2c.h"


#define I2C1_SLAVE_ADDRESS7     0xA0   // EEPROM I2C Address
#define ClockSpeed              200000 // 200 KHz


uint8_t     a=0;


void I2CInit(void);
void I2C1_WriteDeviceRegister(uint8_t , uint8_t , uint8_t );
uint8_t I2C_ReadDeviceRegister(uint8_t , uint8_t );




int main(void)
{  


  I2CInit();


  /*----- Transmission Phase -----*/
  I2C1_WriteDeviceRegister(0xA0 , 0x00 , 0x05);


  /*----- Reception Phase -----*/
  a=I2C_ReadDeviceRegister(0xA0 , 0x00);


  while(1); 


}


void I2CInit(void)
{


  GPIO_InitTypeDef GPIO_InitStructure;
  I2C_InitTypeDef I2C_InitStructure;


  /* Enable GPIO clock */
  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOB, ENABLE);
     
  /* Enable UART clock */
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_I2C1, ENABLE);
     
  GPIO_PinAFConfig(GPIOB, GPIO_PinSource6, GPIO_AF_I2C1);
  GPIO_PinAFConfig(GPIOB, GPIO_PinSource9, GPIO_AF_I2C1);


     
  GPIO_InitStructure.GPIO_OType = GPIO_OType_OD;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_9;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_Init(GPIOB, &GPIO_InitStructure);
  


  I2C_InitStructure.I2C_ClockSpeed = ClockSpeed;
  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;


  /* Enable I2C */
  I2C_Cmd(I2C1, ENABLE);
  I2C_Init(I2C1, &I2C_InitStructure);
}




/*************************/


void I2C1_WriteDeviceRegister(uint8_t DeviceAddr, uint8_t RegisterAddr, uint8_t RegisterValue)
{
/* Send I2C1 START condition */
  I2C_GenerateSTART(I2C1, ENABLE);


  /* Test on I2C1 EV5 and clear it */
 while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_MODE_SELECT));


  /* Send EEPROM slave Address for write */
  I2C_Send7bitAddress(I2C1, DeviceAddr, I2C_Direction_Transmitter);


  /* Test on I2C1 EV6 and clear it */
  while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED));


  /* Send I2C1 EEPROM internal address */
  I2C_SendData(I2C1, RegisterAddr);


  /* Test on I2C1 EV8 and clear it */
  while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_TRANSMITTED));


  /* Send I2C1 EEPROM data */
  I2C_SendData(I2C1, RegisterValue);


  /* Test on I2C1 EV8 and clear it */
  while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_TRANSMITTED));


  /* Send I2C1 STOP Condition */
  I2C_GenerateSTOP(I2C1, ENABLE);
}


/****************************/
uint8_t I2C_ReadDeviceRegister(uint8_t DeviceAddr, uint8_t RegisterAddr)

  uint8_t tmp;


     /* Send I2C1 START condition */
  I2C_GenerateSTART(I2C1, ENABLE);


  /* Test on I2C1 EV5 and clear it */
  while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_MODE_SELECT));


  /* Send EEPROM slave Address for write */
  I2C_Send7bitAddress(I2C1, DeviceAddr, I2C_Direction_Transmitter);


  /* Test on I2C1 EV6 and clear it */
  while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED));


  /* Send I2C1 EEPROM internal address */
  I2C_SendData(I2C1, RegisterAddr);


  /* Test on I2C1 EV8 and clear it */
  while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_TRANSMITTED));


  /* Regenerate a start condition */
  I2C_GenerateSTART(I2C1, ENABLE);
  
  /* Test on I2C1 EV5 and clear it */
  while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_MODE_SELECT));


  /* Transmit the slave address and enable writing operation */
  I2C_Send7bitAddress(I2C1, DeviceAddr, I2C_Direction_Receiver);
  
  /* Test on I2C1 EV6 and clear it */
  while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_RECEIVER_MODE_SELECTED));


  /* End the configuration sequence */
  I2C_GenerateSTOP(I2C1, ENABLE);
  
  /* Load the register value */
  tmp = I2C_ReceiveData(I2C1);


  /* Return the read value */
  return (tmp);
}




#ifdef  USE_FULL_ASSERT
/**
  * @brief  Reports the name of the source file and the source line number
  *         where the assert_param error has occurred.
  * @param  file: pointer to the source file name
  * @param  line: assert_param error line source number
  * @retval None
  */
void assert_failed(uint8_t* file, uint32_t line)
{
  /* User can add his own implementation to report the file name and line number,
     ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */


  /* Infinite loop */
  while (1)
  {
  }
}
#endif

 

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