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App Note (Bluetooth LE-CAN and Bluetooth LE-LIN Bridges on KW36/KW35) Configured Baud Rate different that observed

Question asked by Brendan Johnston on Mar 14, 2019
Latest reply on Apr 15, 2019 by Estephania Martinez

Hi,

I was following the below app note and seem to have encountered a small issue:

https://www.nxp.com/docs/en/application-note/AN12273.pdf

Note: I am using the FRDM-KW36

I followed all the appropriate steps and had the app note up and running properly. I also disabled CAN FD by editing line 26 in the flexcan_interrupt_transfer.c file.

I then tried to detect the CAN messages by attaching another CAN enabled device to the CAN bus and it seemed that the messages I was reading were not valid (I know they are encrypted but this was an actual error). I hooked it up to an oscilloscope and measured the baud rate of the messages to be about 1250000, whereas it seems the example is configured for 1000000 as seen in the fsl_flexcan.c file.

I tried to reconfigure the baudrates and was getting the same issues. Below is a table

Programmed Baud RateActual Baud Rate (Scope)
125000126000
250000270000
500000625000
700000769000
8000001111000
10000001250000

 

I configured the baudrate via the fsl_flexcan.c file (line 612). When I tried adjusting my other CAN enabled device to read the CAN message at the baudrate measured at the oscilloscope the message is successfully read.

 

I'm wondering if there is anything else that I need to configure such that the programmed baud rate is the same as the actual output baud rate. Thank you.

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