receive data uart with DMA

[LOnGr.1]

I am trying to receive data over usart using dma with LL. I'm stuck with this for one week. I need help please.

[waclawek.jan]

Which STM32?

What are the symptoms? Can you receive from the same pin using polling? Are clocks of DMA, USART, GPIO enabled in RCC?

Read out and check/post content of USART, DMA and relevant GPIO registers' content.

JW

[Pavel A.]

https://github.com/MaJerle/stm32-usart-uart-dma-rx-tx

[LOnGr.1]

Hi! Thank you for replying. I tried to send some text using the LL_USART_TransmitData8 and it works fine. Same for receiving with LL_USART_ReceiveData8.

As for the clocks, they're enabled in the clock file

[waclawek.jan]

Which STM32?

Read out and check/post content of USART, DMA and relevant GPIO registers' content.

JW

[LOnGr.1]

stm32 f407

I don't know if the image is clear, but all the registers are empty

[LOnGr.1]

I put the USART2_DMA_RX inside the while loop in the main file and now the red led (transfer complete interrupt) turns on but only when I reset or flash the microcontroller. I tried to do the same for transmission with DMA and it is working fine

[Tesla DeLorean]

Being all zero suggests the clocks aren't enabled when looking at them.

F​or RX make sure all noise, framing, parity errors etc are cleared first.

C​heck that polled RX works, has to be properly receiving.

[LOnGr.1]

Yes it works with polling and transmission with DMA also works. All the clocks are enabled, I checked. I even took the configuration of pins from a working code using registers and as always, TX works fine, RX does not

[waclawek.jan]

If all the UART registers are zero, Tx can't work. It means, you've read out the registers content while UART and DMA were not set up yet - just after reset, perhaps? That's not useful.

Read out the registers after they've been set up, and then again after some characters have been sent to Rx; check, compare, post.

JW