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TCAN4550EVM: Trouble interfacing with MCU

Part Number: TCAN4550EVM
Other Parts Discussed in Thread: TCAN4550

Hello;

I am attempting to interface the TCAN4550 EVM with a non TI MCU and am running into some issues. I am using the example project and changed the AHB functions to fit the SPI library of my chip. 

The SPI appears to be working when watching it with a scope however, no CAN messages are ever sent. When I reset and wake the board manually the nINT and nWKRQ lights are on but after configuration those lights turn off and the INH light turns on. 

My connections are as follows: 

J9: 

VBAT: 12V+ 

GND: SRC GND

J16:

VIO: 3v3 from MCU board (s1 in 3v3 position)

SCLK: MCU SCLK

SDI: MCU MOSI

SDO: MCU MISO

nCS: MCU CS

  • Hi RJ,

    Have you modified the main.c sequence in the demo code? The demo code configures that transceiver and automatically sends a CAN message during start up. It also re-sends a message when a certain button is pressed. Is this the same sequence followed in your setup with your MCU?

    Do you have any way of reading the interrupt register from the TCAN4550? If so, please read the status and interrupt registers to see if there are any problems being reported by the device. This could be done before and after configuration to get the best picture. If you need help with the error meanings, please share your findings with us and we can elaborate. If your setup has a debug mode, it may be helpful to step through each SPI command and see how the transceiver reacts (i.e., when does nINT clear, does CAN react when the transmit command is sent, etc.).

    Because the nINT light turns off, it seems that the interrupts are successfully cleared and the configuration may have gone through correctly. How are you verifying there is no CAN data? Do you have a scope connected to the CANH and CANL lines, or are you trying to interface with another CAN device?

    Regards,
    Eric Schott