i.MX RT Crossover MCUsのトピックRe: use EDMA realize a infinite loop circle queue

use EDMA realize a infinite loop circle queue

wangfan_1987 — Thu, 14 Dec 2023 10:29:20 GMT

Hi,

I have a lot of USART data to receive and continue processing. I want to receive the data in a circular queue in RAM, which is mapped to a DMA receiving area.

I can successfully receive the data and use the EDMA_SetModulo function to let the data "circle" in the RAM. But if the received data counter exceeds the number I set, it stops. I think I can use a DMA interrupt to reset the received data counter, but I worry about the interrupt causing me to miss some incoming data. I want to know if there is another way to tell the DMA to reload the received data counter automatically so that I can receive the data without any interrupt.

Re: use EDMA realize a infinite loop circle queue

wangfan_1987 — Fri, 15 Dec 2023 02:04:21 GMT

I found something strange,when I installed a callback with EDMA_SetCallback，Even through I do nothing in this callback function(just a __NOP() in it),the DMA receive circle queue can continue circle as I need.Maybe there is something I need to config?

Re: use EDMA realize a infinite loop circle queue

_Leo_ — Mon, 18 Dec 2023 15:53:46 GMT

Could you please tell us which device are you using please?

Re: use EDMA realize a infinite loop circle queue

wangfan_1987 — Tue, 19 Dec 2023 09:12:21 GMT

sorry,I missed such important info.

I used IMXRT1176's USART3 as recieving port.If I use EDMA_SetCallback(&lpuart3_Rxdmahandle, lpuart3_dma_receive_callback, NULL) set a function for recieving DMA callback,then the receive can circle.Just comment out it,the DMA is finished if DMA receive counter is reached.

Re: use EDMA realize a infinite loop circle queue

nxf77486 — Fri, 22 Dec 2023 22:07:11 GMT

Hello,

Thank you in advance for contacting NXP support.

Thank you for the information I think the following community post have the information you require for your application.

Please let me know if there is anything else I can do for you.