STM32 spi receive procedure without hal - stm32

Question

Good afternoon,
I am a newbie in the programing of stm32. Just working on a project, where is a serious problem with timing. Trying to implement FOC on the PMSM motor where I need to do a calculation in 50us loop, which is fast to communicate with angle sensor via SPI and HAL. Let me explain the situation.
I tried to work with HAL, but as I read everywhere and explored by myself: if you need speed put it away. So my plan is to use CubeMX to configure all necessary registers and read data directly from the register DR. One small thing, that sensor communicates with a 16-bit frame.
Code that I produce:
__HAL_SPI_ENABLE(&hspi3);
HAL_GPIO_WritePin_Fast(GPIOD, GPIO_PIN_2, GPIO_PIN_RESET); //switch off the pin
hspi3.Instance->DR = 0;
while ((hspi3.Instance->SR & SPI_FLAG_RXNE) == 0){} //Wait for Data Ready to Read
RxData = hspi3.Instance->DR; //Read Data Register Directly
HAL_GPIO_WritePin_Fast(GPIOD, GPIO_PIN_2, GPIO_PIN_SET); // switch on the pin
__HAL_SPI_DISABLE(&hspi3);
Configuration of spi periphery:
/**
* #brief SPI3 Initialization Function
* #param None
* #retval None
*/
static void MX_SPI3_Init(void)
{
/* USER CODE BEGIN SPI3_Init 0 */
/* USER CODE END SPI3_Init 0 */
/* USER CODE BEGIN SPI3_Init 1 */
/* USER CODE END SPI3_Init 1 */
/* SPI3 parameter configuration*/
hspi3.Instance = SPI3;
hspi3.Init.Mode = SPI_MODE_MASTER;
hspi3.Init.Direction = SPI_DIRECTION_2LINES;
hspi3.Init.DataSize = SPI_DATASIZE_16BIT;
hspi3.Init.CLKPolarity = SPI_POLARITY_LOW;
hspi3.Init.CLKPhase = SPI_PHASE_2EDGE;
hspi3.Init.NSS = SPI_NSS_SOFT;
hspi3.Init.BaudRatePrescaler = SPI_BAUDRATEPRESCALER_8;
hspi3.Init.FirstBit = SPI_FIRSTBIT_MSB;
hspi3.Init.TIMode = SPI_TIMODE_DISABLE;
hspi3.Init.CRCCalculation = SPI_CRCCALCULATION_DISABLE;
hspi3.Init.CRCPolynomial = 7;
hspi3.Init.CRCLength = SPI_CRC_LENGTH_DATASIZE;
hspi3.Init.NSSPMode = SPI_NSS_PULSE_DISABLE;
if (HAL_SPI_Init(&hspi3) != HAL_OK)
{
Error_Handler();
}
/* USER CODE BEGIN SPI3_Init 2 */
/* USER CODE END SPI3_Init 2 */
}
In this state, it isn't working, has anyone idea how to solve this issue? Thank you

Answer 1

You have two mistakes:
First, you are reading the data register in the wait loop. You should have an empty loop that does nothing repeatedly until RXNE becomes 1, then read the data.
Second you don't do anything to trigger the clock. In master mode the clock starts when you write data for transmission. After driving the chip-select low, write something to DR:
HAL_GPIO_WritePin_Fast(GPIOD, GPIO_PIN_2, GPIO_PIN_RESET); //switch off the pin
hspi3.Instance->DR = 0; // output something on MOSI while reading MISO
while ((hspi3.Instance->SR & SPI_FLAG_RXNE) == 0){} //Wait for Data Ready to Read
RxByte[0] = hspi3.Instance->DR; //Read Data Register Directly
HAL_GPIO_WritePin_Fast(GPIOD, GPIO_PIN_2, GPIO_PIN_SET); // switch on the pin