RT1176 transfer data through usart at baudrate 921600

[wangfan_1987]

Hi:
I have a large mount of data to transfer through usart,so I need a high speed baudrate.But I meet some problem when change the baudrate.

1. In the baudrate 115200 and 460800,the usart work well,I got the "hello world".
2. When I try to change the baudrate in BOARD_InitDebugConsole() defined by the macro BOARD_DEBUG_UART_BAUDRATE to 921600,I got a garbled code.

I want to know how much is the top baudrate of the usart?Can I do some changes to make the usart work normally.

[Padi-2023 · Accepted solution]

After reading NXP data for an afternoon, please refer to LPC55S1x/LPC551x User manual "UM11295.pdf", I tried to use 1000000bps, RT1176 development board can work normally.

[wangfan_1987]

Since the core frequency of IMXRT1176 is relatively high, configuring it with a baud rate of 921600 should not be a problem. If there are no issues at a baud rate of 1M, then the hardware communication on the circuit board should also be fine. This is a peculiar phenomenon. Nevertheless, thank you for your solution.

[Miguel04]

Hi @wangfan_1987 

I did the testing myself and it works correclty, I only changed the macro value just like you did.

Can you help me sharing the value of the BAUD register?

You can access it while debugging, on the peripherals.

Best Regards, Miguel.

[wangfan_1987]

Thanks for your reply!

My Test board is MIMXRT1176-EVK REVA1,used a USB cable connect the board to PC to transfer usart1 data.

My test program is D:\wangfan\NXP\MIMIX1176\SDK_2_12_0_MIMXRT1170-EVK\boards\evkmimxrt1170\rtos_examples\freertos_hello\cm7

when run the program I want to get "48 65 6C 6C 6F 20 77 6F 72 6C 64 2E" ,which mean "hello world",while I get  "62 AC 3B B8 3E AC 3B 09 FF ".But in baudrate 115200,it was right.

The register value as following:

[Miguel04]

Hi @wangfan_1987 

Can you share with me your IDE version? Your SDK version is 2.12, correct?

I'll look into it and let you know what I found.

Best Regards, Miguel.

[wangfan_1987]

Thanks for your reply! 

My IDE version is KEIL 5.33.0,My compiler is V6.15::ARMCLANG.The SDK pack  name is SDK_2_12_0_MIMXRT1170-EVK.zip,So I think it is the version.I am very thankful for your help!

[Padi-2023]

hi! I also encountered the same problem, so long you should have solved it! May I ask how it is solved? thanks.

[wangfan_1987]

Not sloved,just use a lower baudrate.Maybe core clock problem,if I have enough time,I will tyr to slove.:(

[Padi-2023]

I searched the NXP official website forum and found no solution, I think it is not supported to this piece, 24000000/921600=26.04166666667, 24000000\26=923076.923076, (923076.923076-921600) /921600*100%=0.16%, in fact, the error rate is 0.16%, according to this error rate can be used, even if the interface clock of kCLOCK_Root_Lpuart1 is raised, it may not be solved.

[Padi-2023]

Why do I think this is not supported by this piece? Since the RT685 I am using here is also set with this baud rate, no problems have been found so far

[Miguel04]

Hi @wangfan_1987 

Thank you for the information, however you are using an outdated SDK version and another ide.

I'm using MCUXpresso IDE and this is recommended by NXP to use our platforms, I did not face any issue while using this IDE.

Best Regards, Miguel.