STM32F0 SPI receive interrupt not firing - c

Question

I have a simple project, created using CubeMX for the peripheral initialisation.
SPI is in slave mode, and appears to be initialised correctly, but when I clock 8 bits of data, the interrupt doesn't get called.
Here's the code
/* SPI1 init function */
static void MX_SPI1_Init(void)
{
hspi1.Instance = SPI1;
hspi1.Init.Mode = SPI_MODE_SLAVE;
hspi1.Init.Direction = SPI_DIRECTION_2LINES;
hspi1.Init.DataSize = SPI_DATASIZE_8BIT;
hspi1.Init.CLKPolarity = SPI_POLARITY_LOW;
hspi1.Init.CLKPhase = SPI_PHASE_1EDGE;
hspi1.Init.NSS = SPI_NSS_SOFT;
hspi1.Init.FirstBit = SPI_FIRSTBIT_MSB;
hspi1.Init.TIMode = SPI_TIMODE_DISABLE;
hspi1.Init.CRCCalculation = SPI_CRCCALCULATION_DISABLE;
hspi1.Init.CRCPolynomial = 7;
hspi1.Init.CRCLength = SPI_CRC_LENGTH_DATASIZE;
hspi1.Init.NSSPMode = SPI_NSS_PULSE_DISABLE;
if (HAL_SPI_Init(&hspi1) != HAL_OK)
{
Error_Handler();
}
}
void HAL_SPI_MspInit(SPI_HandleTypeDef* hspi)
{
GPIO_InitTypeDef GPIO_InitStruct;
if(hspi->Instance==SPI1)
{
/* USER CODE BEGIN SPI1_MspInit 0 */
/* USER CODE END SPI1_MspInit 0 */
/* Peripheral clock enable */
__HAL_RCC_SPI1_CLK_ENABLE();
/**SPI1 GPIO Configuration
PA5 ------> SPI1_SCK
PA6 ------> SPI1_MISO
PA7 ------> SPI1_MOSI
*/
GPIO_InitStruct.Pin = GPIO_PIN_5|GPIO_PIN_6|GPIO_PIN_7;
GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
GPIO_InitStruct.Pull = GPIO_NOPULL;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;
GPIO_InitStruct.Alternate = GPIO_AF0_SPI1;
HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
/* Peripheral interrupt init */
HAL_NVIC_SetPriority(SPI1_IRQn, 0, 0);
HAL_NVIC_EnableIRQ(SPI1_IRQn);
/* USER CODE BEGIN SPI1_MspInit 1 */
/* USER CODE END SPI1_MspInit 1 */
}
}
void SPI1_IRQHandler(void)
{
/* USER CODE BEGIN SPI1_IRQn 0 */
/* USER CODE END SPI1_IRQn 0 */
HAL_SPI_IRQHandler(&hspi1);
/* USER CODE BEGIN SPI1_IRQn 1 */
spi_interrupt();
/* USER CODE END SPI1_IRQn 1 */
}
The spi_interrupt() is my specific code for the interrupt actions, and a breakpoint in there never fires.
I've got a scope on the CLKIN pin, and its definitely got the 8 clocks.

Answer 1

ST's HAL library won't enable the actual peripheral interrupts in the initialization function.
For almost all of the peripherals an additional function has to be called which always has the following name structure HAL_<peripheral>_<action>_IT so in case of SPI RX it is called HAL_SPI_Receive_IT.
This enables actually the SPI RX interrupt by setting the correct bit with a macro called: __HAL_SPI_ENABLE_IT(hspi, (SPI_IT_RXNE | SPI_IT_ERR)).
Note that if the number of expected bytes (this value is passed in the HAL_SPI_Receive_IT by the user) is reached then the HAL_SPI_IRQHandler will disable the SPI RX interrupt again, thus a repeated HAL_SPI_Receive_IT call is needed in case of a new reception.