topic Re: UART3 overrun error occurs RT1020 in i.MX RT Crossover MCUs

UART3 overrun error occurs RT1020

hanmant — Mon, 21 Oct 2024 12:07:02 GMT

Hi,

I'm using uart3 interrupt of RT1020 ,i'm using uart3 for rs-485 communication and its speed is 3MBps.

Also, I'm using LPSPI4 CMSIS driver handler for other communication .

Individually uart3 works fine but after adding spi handler , it will start occurring Overrun.

Still im clearing overrun flag but why this flag is getting set .

Also ,one query when this flag set ,in this case will i receive all data or lost

Re: UART3 overrun error occurs RT1020

mayliu1 — Tue, 22 Oct 2024 07:58:09 GMT

Hi @hanmant

Thank you so much for your interest in our products and for using our community.

Usually, there are various causes of UART overrun errors, and it is necessary to consider various aspects such as data processing speed and interrupt processing.

In order to better help you solve the problem, please reply to the question below.
First, Please tell me which DMA_UART interface function you call to receive UART data
Second, Please tell me where and when you call DMA_UART interface function.

I have a few suggestions for you.
1: Set the DMA_UART interrupt priority to be higher than other modules.
2: Use ping pong buffer to receive UART data.

Wish it helps you.
If you still have question about it, please kindly let me know.

Wish you a nice day!

Best Regards

mayliu

Re: UART3 overrun error occurs RT1020

hanmant — Tue, 22 Oct 2024 08:46:17 GMT

Hi @mayliu1 ,

Thanks for reply.

Currently im using DMA uart. I'm using uart interrupt.

Please see below code snippet.

Re: UART3 overrun error occurs RT1020

hanmant — Tue, 22 Oct 2024 08:56:29 GMT

Hi @mayliu1 ,

Please Note Currently im not using DMA uart. I'm using uart interrupt.

Re: UART3 overrun error occurs RT1020

mayliu1 — Tue, 22 Oct 2024 09:13:11 GMT

Hi @hanmant

Thanks for your update information.

If you use UART interrupt to send and receive UART data, every UART byte will trigger a UART interrupt.

Your UART baud rate is very high(3MBps) and will cause frequent entry UART interrupt, which is unreasonable.

I don't recommend you to use the UART interrupt when the UART baud rate is so high.

Best Regards

mayliu

Re: UART3 overrun error occurs RT1020

hanmant — Tue, 22 Oct 2024 09:18:35 GMT

Thanks for reply .
This overrun problem is coming after inclusion of spi cmsis handler.

Re: UART3 overrun error occurs RT1020

mayliu1 — Tue, 22 Oct 2024 09:33:19 GMT

Hi @hanmant

Question: This overrun problem is coming after inclusion of spi cmsis handler.

Answer: Due to the addition of spi cmsis handler, the entry of UART interrupt will be delayed and the UART data cannot be received in time.

mayliu

Re: UART3 overrun error occurs RT1020

hanmant — Tue, 22 Oct 2024 09:43:10 GMT

So , I have to implement DMA uart then?

Re: UART3 overrun error occurs RT1020

mayliu1 — Tue, 22 Oct 2024 09:48:33 GMT

Hi @hanmant

I highly recommend you using the DMA UART , especially when UART baud rate is particularly high.

mayliu

Re: UART3 overrun error occurs RT1020

hanmant — Tue, 22 Oct 2024 12:12:40 GMT

Hi @mayliu1 ,

As per your suggestion i configured uart in DMA but still see the losses.

I can see clear losses at receiver side(my receiver is another device comport).

Re: UART3 overrun error occurs RT1020

mayliu1 — Wed, 23 Oct 2024 04:01:22 GMT

Hi @hanmant

Thank you for your updated information.

Can you tell me when and where you call the DMA UART receive function interface?

"In the source files(lpuart_edma_transfer.c) you sent, I didn't see any calls to the DMA UART data receive interface."

Please try to verify it according to the steps shown below.
1: Set the DMA_UART interrupt priority to be higher than other modules.
2: Use ping pong buffer to receive UART data.

Wish it helps you.
If you still have question about it, please kindly let me know.

Best Regards

mayliu

Re: UART3 overrun error occurs RT1020

hanmant — Wed, 23 Oct 2024 06:00:44 GMT

Thanks for reply.
In this project i only send the data using DMA uart .
So the my receiver is Ti processor device.
I think priority does not matter in this example because here only DMA Uart is running.
I have tried to send 2 bytes of data but still same issue .
Give me solid solution to work this because this simple uart DMA transmission .

Re: UART3 overrun error occurs RT1020

mayliu1 — Wed, 23 Oct 2024 06:13:33 GMT

Hi @hanmant

Thank you for your updated information.

As you said, if you only send UART data, why you ask me UART overrun error happened.

UART overrun error is related with UART receive.

and if you want to send UART data, It is very simple, just call LPUART_SendEDMA.

mayliu

Re: UART3 overrun error occurs RT1020

hanmant — Wed, 23 Oct 2024 06:20:46 GMT

Hi @mayliu1 ,

Thanks for reply.
As of now im not using uart receiver .
whatever i shared with is only uart transmit only (size 52 buffer)but i dont receive correct data on my Ti board using dma.

Re: UART3 overrun error occurs RT1020

mayliu1 — Wed, 23 Oct 2024 07:12:32 GMT

Hi @hanmant

I think I know the reason of the problem.

Continuous data transmission in your program can cause Ti board UART receiver overrun, resulting in abnormal data transfer.

I suggest adding a delay after sending 52 bytes UART data, Please try it.

I have tested and verified this 100 times on my end, and the data sending and receiving are consistent.

Wish it helps you.
If you still have question about it, please kindly let me know.

Re: UART3 overrun error occurs RT1020

hanmant — Wed, 23 Oct 2024 09:42:13 GMT

Thanks for reply.
Can you please share your source code files.

Re: UART3 overrun error occurs RT1020

mayliu1 — Wed, 23 Oct 2024 10:06:49 GMT

Hi @hanmant

Just add a delay function, I have shown to you.

SDK_DelayAtLeastUs(100000, CLOCK_GetFreq(kCLOCK_CpuClk));

1：In addition, I suggest you check whether the data format for UART sending and receiving is consistent.

2：Please confirm whether your NXP development board and TI development board share a common ground.

3：Please confirm whether the connection between UART transmission and reception is secure.

mayliu

Re: UART3 overrun error occurs RT1020

hanmant — Wed, 30 Oct 2024 06:47:21 GMT

Hi @mayliu,

Can you please tell me how to set Highest the Priority to DMA controller over CPU.
Also in DMA i want set the highest priority to UART receive and TX than SPI.
Please tell me the process and API's or any examples.

Re: UART3 overrun error occurs RT1020

mayliu1 — Thu, 31 Oct 2024 03:25:06 GMT

Hi @hanmant ，

Thank you for your updated information.

I suggest you can use NVIC_SetPriority(IRQn_Type IRQn, uint32_t priority)function.

1: The first parameter is IRQn_Type:

It depends on your design, if UART3 using DMA channel 0(#define LPUART_TX_DMA_CHANNEL 0U), then the first parameter is DMA0_DMA16_IRQn.

2:The second parameter is priority, The lower value, the greater the priority of the corresponding interrupt.

Best Regards

mayliu

Re: UART3 overrun error occurs RT1020

hanmant — Thu, 31 Oct 2024 05:17:23 GMT

Hi @mayliu,
I'm thinking add this way,
const edma_channel_Preemption_config_t Channel_preemption_config = {
.enableChannelPreemption = false,
.enablePreemptAbility = true,
.channelPriority = 14U
};
const edma_channel_Preemption_config_t Channel14_preemption_config = {
.enableChannelPreemption = false,
.enablePreemptAbility = true,
.channelPriority = 15U
};

EDMA_SetChannelPreemptionConfig(EXAMPLE_LPUART_DMA_BASEADDR,LPUART_TX_DMA_CHANNEL, &Channel_preemption_config);
EDMA_SetChannelPreemptionConfig(EXAMPLE_LPUART_DMA_BASEADDR, LPUART_RX_DMA_CHANNEL, &Channel14_preemption_config);
is it correct or not.
please confirm