STM32F3 I2C read data

Question

I'm using the STM32F373 microcontroller and wrote a simple function to read data from a MPU6050 gyro+accel on i2c 1 (PB7 PB6). The problem is that when I try to read sensor register data - flag I2C_ISR_TXIS is always equal to RESET (not set). Why might this happen?

Here is some source code that demonstrates the problem.

void i2c1_init(void)
{
  GPIO_InitTypeDef GPIO_InitStructure;
  I2C_InitTypeDef  I2C_InitStructure;
    
  RCC_I2CCLKConfig(RCC_I2C1CLK_SYSCLK);  
  
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_I2C1, ENABLE);  
  RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOB, ENABLE);
  
  GPIO_PinAFConfig(GPIOB, GPIO_PinSource6, GPIO_AF_4);
  GPIO_PinAFConfig(GPIOB, GPIO_PinSource7, GPIO_AF_4);
  
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
  GPIO_InitStructure.GPIO_OType = GPIO_OType_OD;
  GPIO_InitStructure.GPIO_PuPd  = GPIO_PuPd_NOPULL;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6;
  GPIO_Init(GPIOB, &GPIO_InitStructure);
    
  GPIO_InitStructure.GPIO_Pin =  GPIO_Pin_7;
  GPIO_Init(GPIOB, &GPIO_InitStructure);
    
  I2C_DeInit(I2C1);
  I2C_InitStructure.I2C_Mode = I2C_Mode_I2C;  
  I2C_InitStructure.I2C_AnalogFilter = I2C_AnalogFilter_Enable;
  I2C_InitStructure.I2C_DigitalFilter = 0x00;
  I2C_InitStructure.I2C_Ack = I2C_Ack_Enable;
  I2C_InitStructure.I2C_AcknowledgedAddress = I2C_AcknowledgedAddress_7bit;
  I2C_InitStructure.I2C_Timing = 0xC062121F; 
  
  I2C_Init(I2C1, &I2C_InitStructure);  
  I2C_Cmd(I2C1, ENABLE);
}

uint8_t i2c_read(uint8_t DeviceAddr, uint8_t RegAddr, uint8_t* pBuffer, uint16_t len)
{    
  /* Test on BUSY Flag */
  uint32_t timeout = I2C_TIMEOUT;
  while(I2C_GetFlagStatus(I2C1, I2C_ISR_BUSY) != RESET)
  {
    if((timeout--) == 0) return 0;
  }    
  I2C_TransferHandling(I2C1, DeviceAddr, 1, I2C_SoftEnd_Mode, I2C_Generate_Start_Write);
  
  
  /* !!! Wait until TXIS flag is set !!! */
  timeout = I2C_TIMEOUT;
  while(I2C_GetFlagStatus(I2C1, I2C_ISR_TXIS) == RESET) // PROBLEM HERE!!!!!!!!!!!!!!!
  {
    if((timeout--) == 0) return 0;          
  }


  ....
  ....
}

Answer 1

OK,I found the problem. Flag I2C_ISR_TXIS did not get because the device on the i2c did not respond to the sent address. Need to convert the device address to 7 bits.

(DeviceAddr & 0x7f) << 1