STM32F4 SPI Receive interrupt not working

Question

I am working on a project where I am using two boards to communicate via SPI. The master board (TMS320F28377S) is sending data successfully via SPI, I'm attaching a screenshot of the scope with CLK, MOSI, and SS pins. master data

Now, my receiver board is running on a STM32F439 processor, I'm relatively new to this micro. I configured it as a a Receiver Only using CubeMX, rest of settings are show below,

hspi2.Instance = SPI2;
hspi2.Init.Mode = SPI_MODE_SLAVE;
hspi2.Init.Direction = SPI_DIRECTION_2LINES_RXONLY;
hspi2.Init.DataSize = SPI_DATASIZE_8BIT;
hspi2.Init.CLKPolarity = SPI_POLARITY_LOW;
hspi2.Init.CLKPhase = SPI_PHASE_1EDGE; 
hspi2.Init.NSS = SPI_NSS_HARD_INPUT; //??
//hspi2.Init.NSS = SPI_NSS_SOFT; 
hspi2.Init.FirstBit = SPI_FIRSTBIT_MSB;
hspi2.Init.TIMode = SPI_TIMODE_DISABLE;
hspi2.Init.CRCCalculation = SPI_CRCCALCULATION_DISABLE;
hspi2.Init.CRCPolynomial = 10;

As it can be seen on scope, CPHA and CPOL settings are matched for both boards (low clk when idle, and sample on leading edge).

Once the code is ready for receiving, I call the following,

if(HAL_SPI_Receive_IT(&hspi2, (uint8_t *)GEU_RX_Buffer, 2) != HAL_OK)
{
    Error_Handler();    
}
                
while(1){}

I'm placing a breakpoint in the, setting a variable and calling receive interrupt again

void HAL_SPI_RxCpltCallback(SPI_HandleTypeDef *hspi)
{
    Sys_Mode = DIAGNOSTIC_MODE;

    // Trigger interrupt again to keep receiving datas
    HAL_SPI_Receive_IT(&hspi2, (uint8_t *)rx_buffer, 2);
}

When I make a transfer from master, I'm watching rx_buffer variable and no data is being received, also RXNE flag is not being set.

Is there something I'm missing here? All I want is to be able to receive data on another platform in non-blocking mode using interrupt. Also, should I have the NSS pin physically connected to an I/0 on the receiver micro?

Your help is appreciated in advance.

Thank you.

Gil

Simson · Accepted Answer · 2021-02-04 09:44:55Z

1

AFAIK HAL_SPI_RxCpltCallback is only triggered by an DMA interrupt. You should either try to change HAL_SPI_Receive_IT to HAL_SPI_Receive_DMA or implement the handler for HAL_SPI_Receive_IT in the xxx_it.c file.

From my point of view (with very little experience at this specific topic ...) it looks like you're waiting on the wrong interrupt.

edited Feb 4, 2021 at 9:44

Simson

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answered Jan 30, 2021 at 21:16

Chris_B

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1 Comment

GMAN_82 Over a year ago

I realized the NSS pin was pulled out wrong on my custom hardware. Thank you! Best, Gil

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