CAN0 H current in MPC5748G

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CAN0 H current in MPC5748G

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assidinedia2
Contributor I

Hey all,
We are trying to send data with CAN0 (using examples on S32 DS: flexcan_transmit and can_pal_mpc5748g) on MPC5748G Dev Kit.
We're testing CAN H and CAN L using Led and the current seems to be higher than the expected value in the datasheet (We tested the same frame using TJA1050 Shield and Raspberry Pi). We wanted to transmit and receive data using our devkit and other raspberry pi bords.
Could you help us, please?
Thanks in advance

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5 Replies

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assidinedia2
Contributor I

Hi,

Yes, there are errors as shown below that's why we couldn't receive the message sent by the Devkit to the raspberry pi.

Regards, 

Lark20200701-151608.png

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PetrS
NXP TechSupport
NXP TechSupport

Hi,

I can advice to check if DEVKIT is sending a message. Leave it unconnected from teh bus and send a message.

You should see message still on CANH/CANL lines as it is not ACKed and TXerror counter should be 0x80.

Then check a bit timing setting on all nodes, if same bitrate and sample point is selected.

BR, Petr

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assidinedia2
Contributor I

Thank you for replying.

So, we connected two raspberry pi boards and our devkit to a CAN bus, the communication between two raspberry boards (MCP2515 Shield and TJA1050) worked fine but when we add our devkit it just blocks. That's why we wanted to test signal output via LEDs.

Using the LED, the light intensity was weak when checking raspberry outputs but higher with our dev board.

We would appreciate it if you can help us connecting our board and raspberry board to transmit and receive data because that's our main issue.

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PetrS
NXP TechSupport
NXP TechSupport

Hi,

what does "it just blocks" mean after DEVKIT is connected to the bus? Do you see any CAN errors detected on MCP2515 or MPC5748G, check error counters and status registers.

Is the bus signals expected?

BR, Petr

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PetrS
NXP TechSupport
NXP TechSupport

Hi,

I do not understand the testing you did. Can you specify it more and describe the issue you have.

I do not expect any problems when connecting DEVKIT and other raspberry pi boards via CAN bus if the bus will be properly terminated and bitrate with sample point correctly set.

BR, Petr 

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