topic Re: MQX 4.2 Kinetis Serial DMA in MQX Software Solutions

MQX 4.2 Kinetis Serial DMA

kfranz — Mon, 14 Mar 2022 18:51:47 GMT

In MQX 4.2 there is a file named serl_dma_kuart.c

Freescale_MQX_4_2\mqx\source\io\serial\dma\serl_dma_kuart.c

Are there any examples that use DMA for the UART? I would like to change from the interrupt driven driver to one that uses DMA so that I can run at a higher baud rate.

Will using DMA reduce or eliminate serial port interrupts?

Re: MQX 4.2 Kinetis Serial DMA

kfranz — Mon, 14 Mar 2022 20:17:48 GMT

I am using the K65. In:

C:\Freescale\Freescale_MQX_4_2\mqx\source\bsp\twrk65f180m\initbsp.c for ittya, I made the changes below:

#if BSPCFG_ENABLE_ITTYA
//_kuart_int_install("ittya:", &_bsp_sci0_init, _bsp_sci0_init.QUEUE_SIZE);
_kuart_dma_install("ittya:", &_bsp_sci0_init, _bsp_sci0_init.QUEUE_SIZE);
#endif

It seems to be working okay. I assume I am now using DMA?

Re: MQX 4.2 Kinetis Serial DMA

kfranz — Mon, 14 Mar 2022 23:34:43 GMT

No, UART DMA is not working.

Does anyone have any suggestions?

Re: MQX 4.2 Kinetis Serial DMA

danielchen — Sat, 19 Mar 2022 12:21:01 GMT

Hi kfranz:

The checked this, and the UART DMA is not documented. It looks like the files were added for future release. But now MQX 4.x is replaced by MQX v5. Please refer to below link for more details.

https://www.nxp.com/design/software/embedded-software/mqx-software-solutions/mqx-v5-software-solutions:MQX-V5

I would suggest you do more test on your side.

Regards

Daniel