Kinetis MicrocontrollersのトピックRe: FRDM KW36 - UART Rx Overrun issue in 1mbps BPS

FRDM KW36 - UART Rx Overrun issue in 1mbps BPS

dileep_divakara — Wed, 19 Jun 2019 08:49:00 GMT

Hi,

I am working on FRDM KW36 board. I am getting UART Rx overrun issue while receiving packets at baudrate more than 750kbps. It is woking fine upto 500 kbps baudrate.

Here is the code snippet for LPUART initialization

#define LPUART_BUFFER_LENGTH 1

#define BRIDGE_LPUART_BAUDRATE 1000000

CLOCK_SetLpuart1Clock(0x01U); //MCGFLLCLK - 40Mhz

LPUART_GetDefaultConfig(&config);
config.baudRate_Bps = BRIDGE_LPUART_BAUDRATE;
config.enableTx = true;
config.enableRx = true;

LPUART_Init(BRIDGE_LPUART, &config, BRIDGE_LPUART_CLK_FREQ);

LPUART_TransferCreateHandle(BRIDGE_LPUART, &g_lpuartHandle, __lpuart_driver_callback, NULL);

receiveXfer.data = g_rxBuffer;
receiveXfer.dataSize = LPUART_BUFFER_LENGTH;
LPUART_TransferReceiveNonBlocking(BRIDGE_LPUART, &g_lpuartHandle, &receiveXfer, NULL);

Please help me to figure out the issue. What is the maximum baud-rate that can be achieved in the FRDM KW36 board. Actually we are looking for 3mbps baudaret. please help me on this

Note :In release build, 1mbps baudrate is woking fine, But the same code gives UART rx overrun error in debug build.

Thanks in Advance

Re: FRDM KW36 - UART Rx Overrun issue in 1mbps BPS

mjbcswitzerland — Wed, 19 Jun 2019 17:55:57 GMT

At high baud rates you need to use DMA to ensure no overrun can take place. Interrupt or polling is likely to fail at some point and be generally unreliable due to the hard reaction delay requirements.

Regards

Mark

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Re: FRDM KW36 - UART Rx Overrun issue in 1mbps BPS

tangchaozheng — Wed, 26 Jun 2019 08:12:35 GMT

Excuse me, do you know to modify the data receiving buffer of FRDM KW36, that is, RX buffer, thank you very much for answering my question.

Re: FRDM KW36 - UART Rx Overrun issue in 1mbps BPS

tangchaozheng — Wed, 26 Jun 2019 08:13:58 GMT

Excuse me, do you know to modify the data receiving buffer of FRDM KW36, that is, RX buffer? thank you very much for answering my question.

Re: FRDM KW36 - UART Rx Overrun issue in 1mbps BPS

mario_castaneda — Thu, 27 Jun 2019 18:03:38 GMT

Hi Tang,

In the case of UART, you could take a look at the driver example for LPUART included in the SDK of the KW36. In that example, the size of the buffer can be changed, maybe it will be useful to you

Regards,

Mario

Re: FRDM KW36 - UART Rx Overrun issue in 1mbps BPS

tangchaozheng — Fri, 28 Jun 2019 00:41:21 GMT

First of all, thank you very much for answering my question. In the lpuart-related driver, I only saw a code that modifies the ring buffer. I don't know if this modification can work. After the modification, the LPUART_ReadBlocking function can be used to receive data when receiving data.

Re: FRDM KW36 - UART Rx Overrun issue in 1mbps BPS

mario_castaneda — Mon, 01 Jul 2019 17:18:32 GMT

Hi Tang,

I think you had posted this question.

https://community.nxp.com/thread/506293

Regards,

Mario

Re: FRDM KW36 - UART Rx Overrun issue in 1mbps BPS

tangchaozheng — Wed, 03 Jul 2019 01:07:19 GMT

Yes, I am asking for help from many people, of course I also thank you for answering my question.