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TCAN4550EVM: cannot be changed to Normal mode.

Part Number: TCAN4550EVM
Other Parts Discussed in Thread: TCAN4550

Dear SIr,

My customer is programing register for below sequence. but It is not changed mode from Standby to Normal.

Could you advise me about this issue?

1. Check if the current mode of TCAN IC is Standby Mode. If it is not in Standby mode, change the value of 0x0800 [7: 6] to 1 through SPI Write.
2. Check the CCE, INIT values by reading the M_CAN CCCR value, and change it to 1 if it is not 1. Here, we confirm that the CSR value is also 1.
3. Since we do not use CAN_FD, we do not configure it.
4. Set the Watchdog Timer.
5. Set CAN timing.
6. Set the MRAM settings as shown in Table 7 on page 11 of the file sent as an attachment to the mail below.
7. To change the mode of TCAN IC to Normal mode, set 0x0800 [7: 6] to 2 and execute SPI Write. However, after sending the SPI Write command, the confirmation mode cannot be changed to Normal mode.

  • Hi Dexter,

    The sequence you describe sounds good. It appears that it should initialize TCAN4550 while it is in Standby mode before returning it to its operating Normal mode. 

    Could you please share more information about the state of the device before and after the write to return to Normal mode (step 7)?
    a) Is the controller receiving a response via SPI before or after the write to return to normal mode?
    b) When MODE_SEL (0x0800[7:6]) is read after step 7, does it still read 01 indicating the device is still in Standby mode?
    c) How much time elapses between the switching to Standby mode and the attempt to return to Normal mode? Order of seconds? Minutes?
    d) Can you confirm that the power supply for the device is stable during this time? Do you see any fluctuations on VccOut?

    Regards,
    Eric

  • Dear Sir,

    please refer to the below answer.

    a) Is the controller receiving a response via SPI before or after the write to return to normal mode?

    after th write to return to standby mode.


    b) When MODE_SEL (0x0800[7:6]) is read after step 7, does it still read 01 indicating the device is still in Standby mode?
    Yes, the device still in standby mode.

    c) How much time elapses between the switching to Standby mode and the attempt to return to Normal mode? Order of seconds? Minutes?

    i don't know How much time elapses. i think the device doesn't in standby mode.

    d) Can you confirm that the power supply for the device is stable during this time? Do you see any fluctuations on VccOut?
    There in no any fluctuations on VccOut.

  • Hi Dexter, 

    This does sound strange. After MODE_SEL has been received a write command to return the device to normal mode, it should read back the new device state. A case where this would not be true is if the device is in sleep mode with SPI disabled. This can occur if the device is left idle for a minute or so, but also disables the SPI interface so you would not be able to read the device mode using this method.

    Would you be able to share your code with me? If it is similar to the Demo code available on the store page you may share what significant changes you've made. If not, please include an overview of he program so I can best understand and follow the desired functionality. You may choose to share here on the public forum or email it to me directly. Find my email by clicking on my E2E name.

    Regards,
    Eric

  • Dear Eric,

    I will sent  you email directly.

    Thanks.