Mbed forum

Nucleo CAN on MBED online


(IUT HAGUENAU) #1

Hello we have to realize a project under MBED.
For this purpose, we have a NUCLEO-F446RE card.

We have already managed to communicate in SPI connection and read on the PC but currently we are blocking on the CAN connection.

We have a system that sends frames and has been validated as well as a module to transform CAN LOW and CAN HIGH into TX and RX using an MCP2551 module. This system has been tested and we are sure it works since we can display the output frames on an oscilloscope. However, we want to display on the PC using our NUCLEO and a program under MBED but our display does not work. We use the example program suggested by MBED in its CAN function via the mbed library.
We also looked at the oscilloscope at the output of our board and noticed that the TX influences the RX. Is that normal? Because this seems unlikely to us.

Are there any basic things to know that are not explicit and that block our program?
We have tried to do some tests but we are currently blocking.

Also, we are French so please forgive our approximate English.
Thanks for your answer.


(Desmond Chen) #2

We may need the following information for better addressing this issue.

Could you attach the waveform of TX influencing RX, and the source code if possible.

Which version of mbed-os are you using? You can use “mbed releases” to get the mbed-os version.


(IUT HAGUENAU) #3

Hi ,
Thanks for the answer. Sorry with the Christmas Holidays, we didn’t see the answer.
Our waveform are on a specific oscilloscope so we can’t send them before monday.
For the mbed, we use the online one ( https://ide.mbed.com/compiler/#nav:/; )


(IUT HAGUENAU) #4

Up


(Desmond Chen) #5

Hope you are doing well.

Here is a topic related to CAN, if you put CAN read in ISR, that may cause some problems, could you check if you hit the same problem?