STM G4 FIFO and DMA questions

[MartinK]

- Use MCU :  STM32G473VET

- Use connectivity : SPI 3 

 -> Mode : Full-Duplex Slave

1. It it possible to clear Tx FIFO??

"FTLVL" It's not '0' value. how to make '0'?

The code used is :

1)

if(spi3_cs_low == true){

HAL_SPI_Transmit_DMA(&hspi3, aTxBuffer, 11);
HAL_DMA_STATE_CHANGE(&hspi3);
HAL_SPI_Receive_DMA(&hspi3, aRxBuffer, 11);
HAL_DMA_STATE_CHANGE(&hspi3);

}

or

2)

if(spi3_cs_low == true){

 HAL_SPI_TransmitReceive_DMA(&hspi3, (uint8_t *)aTxBuffer, (uint8_t *)aRxBuffer, 11);

}

-- Send data when CS is low and receive the same data many times.

-- Is there a code to add?

2. Do I have no choice but to receive Data to update DMA Tx data ?

I want to send.

SLAVE FIFO buffer update continues. and

I would like to send last SLAVE FIFO buffer when I request MASTER writing.

Is that possible??

Thank you. I need your help!!

[Saket_Om]

Hello @MartinK 

1. It it possible to clear Tx FIFO??

There is no possibility to clear these bits by software. these bits are fully managed by hardware. Please take a look at the description provided in the reference manual below. 

2. Do I have no choice but to receive Data to update DMA Tx data?

To answer your question, we need to know what the slave device is you are communicating with. If I understand correctly, your application is designed to send and receive data in a loopback configuration.