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I2C on STM32F4 gets stuck while checking EV6 flag

Question asked by schilling.robert on May 26, 2012
Latest reply on Sep 1, 2013 by moshiri.ramin
Hi guys,

I'm working on a STM32F4 Discovery board and trying send over I2C. Therefore I'm using the functions from the Standard Peripheral Library. Unfortunately the device stucks after sending the address while checking the I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED

Here is my initialization:
#define IMU_I2C                          I2C1
#define IMU_I2C_CLK                      RCC_APB1Periph_I2C1
#define IMU_I2C_SCL_PIN                  GPIO_Pin_6         
#define IMU_I2C_SCL_GPIO_PORT            GPIOB                 
#define IMU_I2C_SCL_GPIO_CLK             RCC_AHB1Periph_GPIOB
#define IMU_I2C_SCL_SOURCE               GPIO_PinSource6
#define IMU_I2C_SCL_AF                   GPIO_AF_I2C1
#define IMU_I2C_SDA_PIN                  GPIO_Pin_9                 
#define IMU_I2C_SDA_GPIO_PORT            GPIOB                      
#define IMU_I2C_SDA_GPIO_CLK             RCC_AHB1Periph_GPIOB
#define IMU_I2C_SDA_SOURCE               GPIO_PinSource9
#define IMU_I2C_SDA_AF                   GPIO_AF_I2C1
void i2c_init(void)
  GPIO_InitTypeDef GPIO_InitStructure;
  I2C_InitTypeDef I2C_InitStructure;
  // Enable Clk
  RCC_APB1PeriphClockCmd(IMU_I2C_CLK, ENABLE);
  // Performing a Reset
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_SYSCFG, ENABLE);
  RCC_APB1PeriphResetCmd(IMU_I2C_CLK, ENABLE);
  // Remap Pins
  // Initialize SCL
  GPIO_InitStructure.GPIO_Pin = IMU_I2C_SCL_PIN;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_InitStructure.GPIO_OType = GPIO_OType_OD;
  GPIO_InitStructure.GPIO_PuPd  = GPIO_PuPd_NOPULL;
  GPIO_Init(IMU_I2C_SCL_GPIO_PORT, &GPIO_InitStructure);
  // Initialize SDA
  GPIO_InitStructure.GPIO_Pin = IMU_I2C_SDA_PIN;
  GPIO_Init(IMU_I2C_SDA_GPIO_PORT, &GPIO_InitStructure);
  // I2C configuration
  I2C_InitStructure.I2C_Mode        = I2C_Mode_I2C;
  I2C_InitStructure.I2C_DutyCycle   = I2C_DutyCycle_2;
  I2C_InitStructure.I2C_OwnAddress1 = 0;
  I2C_InitStructure.I2C_Ack         = I2C_Ack_Enable;
  I2C_InitStructure.I2C_AcknowledgedAddress = I2C_AcknowledgedAddress_7bit;
  I2C_InitStructure.I2C_ClockSpeed = 100000;
  I2C_Init(IMU_I2C, &I2C_InitStructure);

My sending function is like the examples from ST but it stucks after sending the address while checking the EV6 flag.

void i2c_write_buf(uint8_t address, uint8_t* buf, int32_t len)
  while(I2C_GetFlagStatus(I2C1, I2C_FLAG_BUSY));
  /* 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 slave Address for write */
  I2C_Send7bitAddress(I2C1, address, I2C_Direction_Transmitter);
  /* Test on I2C1 EV6 and clear it */
  while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED)); //I2C stucks here!!!
    /* Send I2C1 slave register address */
    I2C_SendData(I2C1, *buf++);
    /* Test on I2C1 EV8_2 and clear it */
    while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_TRANSMITTED));
  /* Send I2C1 STOP Condition */
  I2C_GenerateSTOP(I2C1, ENABLE); 

For initialization and sending I followed the examples from ST. On the I2C pins the is a magnetometer with external pullups. 

Does anyone know where there is a mistake??

Thanks, Robert