STM32 I2C Stop Condition wird nicht bearbeitet

uint8_t i2c_read(uint8_t slave_addr, uint8_t register_addr)

{

  volatile uint32_t temp;

  uint8_t buffer;

  I2C_TypeDef *I2Cx = I2C1;

  // Generate START condition and wait for EV5

  while (I2C_GetFlagStatus(I2Cx, I2C_FLAG_BUSY));

  I2C_GenerateSTART(I2Cx, ENABLE);

  while (!I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_MODE_SELECT));

  // Send slave address and wait for EV6

  slave_addr <<= (uint8_t) 1;

  I2C_Send7bitAddress(I2Cx, slave_addr, I2C_Direction_Transmitter);

  while (!I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED));

  while (I2C_GetFlagStatus(I2C1, I2C_FLAG_ADDR));

  // Wait for EV8_1

  while (!I2C_GetFlagStatus(I2Cx, I2C_FLAG_TXE));

  // Send register address and wait for EV8_2

  I2C_SendData(I2Cx, register_addr);

  while (!I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_BYTE_TRANSMITTED));

   // Generate (re)start condition and wait for EV5

  I2C_GenerateSTART(I2Cx, ENABLE);

  // Send slave address and wait until ADDR = 1

  slave_addr |= (uint8_t) 0x01;

  I2C_Send7bitAddress(I2C1, slave_addr, I2C_Direction_Receiver);

  while (!I2C_GetFlagStatus(I2C1, I2C_FLAG_ADDR));

  // clear ACK bit

  I2Cx->CR1 &= (uint16_t) ~I2C_CR1_ACK;

  temp = I2Cx->SR1;

  temp = I2Cx->SR2;

  while (I2C_GetFlagStatus(I2C1, I2C_FLAG_ADDR));

  I2Cx->CR1 |= I2C_CR1_STOP;

  // Wait until data has been received in DR register (RXNE = 1) -> EV7

  while (!I2C_GetFlagStatus(I2Cx, I2C_FLAG_RXNE));

  // Read the data

  buffer = I2C_ReceiveData(I2Cx);

  // Make sure that the STOP bit is cleared by Hardware before CR1 write access

  while (I2Cx->CR1 & I2C_CR1_STOP);

  // Enable Acknowledgement to be ready for another reception

  I2Cx->CR1 |= I2C_CR1_ACK;

  return buffer;

}