MSPM0L1306: Enable UART RTFG timeout interrupt for DMA transfers

Munan Xu

Part Number: MSPM0L1306

Tool/software:

Hello,

I have a customer who's trying to receive an arbitrary length UART transmission with DMA.

He's got the dma transfer configured for single byte transfer, with a MAX length transfer, expecting at some point the transmitter will stop sending data and the time out interrupt will get asserted to actually end the UART transfer.

However, this only works for a single byte UART packet, if he sends more data than that, the UART never times out, but the data does get transferred into SRAM.

I did see that the RTFG only gets asserted if there's data "left over" in the FIFO or the RX register, but if the DMA is configured correctly this would never happen, so how are you supposed to use the DMA in the timeout feature in this case?

Munan

6 months ago

0 Cash Hao11 6 months ago

TI__Mastermind 45685 points

Hi Munan,

My colleague will reply into this thread in a short time. Thanks for understanding!

Best regards,

Cash Hao

0 Yuhao Zhao 6 months ago in reply to Cash Hao11

TI__Genius 9780 points

What you observed follows the spec. The FIFO will be transfer immediately via DMA. In fact DMA is suitable for certain length comms.

0 Munan Xu 6 months ago in reply to Yuhao Zhao

TI__Expert 4940 points

Hi Yuhao,

Yes but that is not the behavior that the customer wants. They would like to be able to use DMA with UART transfers of unknown length. So what they would like is to be able to use the RTFG to indicate that the UART has not received any data in the last x number of BRCLK.

I'm asking for you to provide a suggestion on how it might be possible to receive a UART transfer of unknown length while still using DMA.

Munan

0 Yuhao Zhao 6 months ago in reply to Munan Xu

TI__Genius 9780 points

Here is one solution using UART+ 2DMA + TIMER.

(4) [FAQ] UART RX ms-level timeout realization based on Event for MSPM0 - MSP low-power microcontroller forum - MSP low-power microcontrollers - TI E2E support forums

0 Munan Xu 5 months ago in reply to Yuhao Zhao

TI__Expert 4940 points

Hi Yuhao,

Thanks for sharing, I'll send to the customer, but this is a very resource heavy implementation for such function. Just note that our competition has this type of functionality based on basically an RX timeout counter in the UART peripheral.

Munan

0 Yuhao Zhao 5 months ago in reply to Munan Xu

TI__Genius 9780 points

Thanks for the comments, I will send the feedback to our System.

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MSPM0L1306: Enable UART RTFG timeout interrupt for DMA transfers