topic Re: UART4 DMA on K66 in Kinetis Software Development Kit

UART4 DMA on K66

biafra — Mon, 04 Oct 2021 10:41:17 GMT

Hi everyone,

I'm using a custom board with K66.

I'm using UART4 to handle modbus protocol (half duplex) and I'd want to handle it with DMA.

UART4 has a shared request for tx and rx DMA: in this post it's written that it's not possible to use UART4 DMA to handle full duplex tx and rx.

Is it possible to use UART4 DMA for half duplex communication?

If so, how can I configure the DMA to hanlde this situation?

Many thanks

Biafra

Re: UART4 DMA on K66

jingpan — Mon, 11 Oct 2021 07:11:51 GMT

Hi @biafra

Yes, of course you can use UART4 DMA for half duplex communication. But software has to do lots of work to switch DMA work mode. I think it's no good than interrupt mode.

Regards,

Jing

Re: UART4 DMA on K66

biafra — Mon, 11 Oct 2021 07:28:57 GMT

Hi @jingpan,

Many thanks for yor answer.

My problem is the speed: at higher bps it's a little bit hard to receive correctly all the packets (UART4 has only 1 byte FIFO), so the solution seems to use DMA.

Is there any example to configure the UART4 and DMA in such situation?

Many thanks

Biafra

Re: UART4 DMA on K66

jingpan — Wed, 13 Oct 2021 07:25:08 GMT

Hi,

No, there isn't.

Regards,

Jing