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Problem with k64f uart3 receiving bad data

Question asked by Thomas on May 24, 2018
Latest reply on May 24, 2018 by Thomas

Hi, I'm working on the frdm k64f board and i'm trying to initialize the uart3 and send data in and out. I have been trying to figure out this, debugging, researching, and trying different examples but still no success.

 

For uart0 which uses the micro USB interface just works straight from the demo apps. However, when I configure the uart3, I am getting data back but the data seems to be wrong and contains noise. Here is the first setup that I tried on uart3 PTC16/17.

 

 


My most recent attempt was following this example UART3  because it was confirmed successful by someone else (FRDM-K64F - UART3 Issues With KSDK 2.0). So data was coming back fine on uart1, here's the output:

ascii:
Uart functional API interrupt example
Board receives characters then sends them out
Now please input:

hex:
55 61 72 74 20 66 75 6E 63 74 69 6F 6E 61 6C 20 41 50 49 20 69 6E 74 65 72 72 75 70 74 20 65 78 61 6D 70 6C 65 0D 0A 42 6F 61 72 64 20 72 65 63 65 6 9 76 65 73 20 63 68 61 72 61 63 74 65 72 73 20 74 68 65 6E 20 73 65 6E 64 73 20 74 68 65 6D 20 6F 75 74 0D 0A 4E 6F 77 20 70 6C 65 61 73 65 20 69 6E 70 75 74 3A 0D 0A 00

 

When I initialized the uart3 (PTB10/11) and followed the example EXACTLY, I am getting back data, however just like the other times, it's not expected data, here's the output:

in ascii:
f3<?`?fó†ž<`?†žþžøž<àž˜`33˜˜†ž`?f<??f?Ÿ`?˜†üfÀfÏðÏfÃf€æž<?`<ÃfÃæàfÃf̆~3xóü`ÌàÌfÀ†øfÀæàófÆøæøÀæÌfÆž˜øfÆž`<?ÌÌfÃfÏÀÌžf?`?怘€ø˜þž~?ÀÏfÃfÀæøfÃÀ̘†žŸf?`?˜˜03`

in hex:
66 33 06 3C 18 3F 60 3F 00 18 0F 66 F3 86 9E 1E 3C 60 3F 86 9E FE 9E F8 9E 06 3C E0 9E 00 98 00 19 60 33 18 33 00 98 98 86 9E 60 3F 66 3C 18 3F 18 3F 66 06 F0 06 F3 06 60 CC C3 06 FC 66 C0 66 CF 06 F0 06 CF 66 C3 66 0F 0C 06 0C 80 E6 9E 06 3C 18 3F 60 3C 00 18 C3 66 C3 E6 E0 66 C3 66 CC 86 7E 33 78 F3 FC 06 60 CC E0 06 CC 66 C0 86 F8 66 C0 E6 E0 06 F3 66 C3 86 F8 E6 F8 06 C0 0C E6 06 CC 66 C3 86 9E 00 98 F8 66 C3 86 9E 60 3C 1E 3F 00 18 CC 06 CC 66 C3 66 CF 06 C0 CC 9E 66 3F 60 3F E6 80 98 80 F8 98 FE 9E 7E 3F 00 18 C0 06 CF 66 C3 66 C0 E6 F8 66 C3 06 C0 CC 98 86 9E 00 9F 66 3F 60 3F 98 98 1E 30 33 60 00

 

I also captured it on a Logic Analyzer and I am seeing these red F's, can anyone help explain? I am really scratching my head. Thank you.

 

Attached is also the full capture.

Any help is appreciated.

Thank you,

RT

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