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AM62A7: UART boot issues

Radu Suma
Prodigy 10 points
Part Number: AM62A7


Tool/software:

Hi, 

  I'm using an AM62A7 on our custom board and i'm trying to get the board to set UART boot by toggling the soc boot pins. The hardware has been reworked to get to toggle the pins in different states. The hardware rework was checked twice and it has no issues. I have had the possibility to change the state of the pins last year but recently i cannot do it anymore. 

The only boot state where i can observe the target is getting past the boot hand is when i set it to serial NAND boot and i see that a pre-flashed program starts to blink an LED. But when i switch it to uart boot there should be "C" characters printed on one of the serial terminal, and after that i could send the binaries to the target. 

Any ideas on what to check or what could be the cause of this behavior is appreciated. 

  • 0
    TI__Guru 51768 points

    Hi Radu,

    Thanks for your query.

    How are you confirming that the EVM is in UART boot mode if no 'C' characters are printed on the UART console?

    Regards,

    Tushar

  • 0 in reply to Tushar Thakur
    Prodigy 10 points

    Hello , 

       The AM62 is now on our own board and i have reworked the board to connect the boot pins to an external switch. I have used that switch in the past to switch between boot modes and it worked in the past. I could see the "C" characters in uart mode but right now i can only see the board going into NAND boot when i set all 4 switches to off. I could see characters being printed on uart and an led was blinking on the board so what was originally flashed was booted. 

    I have rechecked the hardware rework 3 times with different colleagues so there is a minimal chance of something being wrong with it and seeing the board going into NAND boot shows that the switches are working.  

  • 0 in reply to Radu Suma
    TI__Guru 51768 points

    Hello Radu,

    Can you please try reading the DEVSTAT register to check whether the bootmode values are being updated properly or not?

    Please refer below image.

    Regards,

    Tushar

  • 0 in reply to Tushar Thakur
    Prodigy 10 points

    How can i attempt to read that register? All my teraterm windows are empty when i try to boot the board. All i can see is a "hello world" from the R5 when i set it to NAND boot. What is outputed must be a simple program pre-flashed. 

  • 0 in reply to Radu Suma
    TI__Guru 73271 points

    Hello,

    Have you made sure the Teraterm is connected to the UART0 with the right configuration for observing the C characters?

    Radu Suma said:
    All i can see is a "hello world" from the R5 when i set it to NAND boot.

    In this bootmode, you should also see the SBL logs on the UART0 port. Do you not see them?

    https://software-dl.ti.com/mcu-plus-sdk/esd/AM62AX/10_01_00_33/exports/docs/api_guide_am62ax/EVM_SETUP_PAGE.html#:~:text=You%20should%20see%20output%20like%20below%20on%20the%20UART%20terminal

    Regards,

    Prashant

  • 0 in reply to Prashant Shivhare
    Prodigy 10 points

    Hello ,

    I made some screen shots, i only see an output when setting to serial NAND booting. 

    This is over a few power cycles. 

    And when i set it to uart boot it doesn't display anything. 

    I also have a XDS110 debug probe. Can i use it to check the DEVSTAT register like you mentioned? If yes, are there any instructions on how to ?

  • 0 in reply to Radu Suma
    TI__Guru 51768 points

    Hi Radu,

    Apologies, but can you please summarize the issue.

    I can see you are now able to see the 'C' character on COM port when board is kept in UART boot mode which is expected behaviour.

    I can also see you are able to see hello world coming on COM ports when board is in OSPI NAND boot mode.

    Can you please tell what is issue that you are currently facing?

    Regards,

    Tushar

  • 0 in reply to Tushar Thakur
    Prodigy 10 points

    Hi,

     To summarize the issue, i cannot get into UART boot state, what you see above in the screens is when it is set to NAND boot. 

    When i set to uart boot, nothing happens, and it should print out "C" characters .

  • 0 in reply to Radu Suma
    TI__Guru 51768 points

    Hi Radu,

    I think there is some sort of confusion here.

    Can you please re-share the screenshots with Tags to identify which image belongs to which boot mode?

    Below is the expected behavior.

    In UART boot mode, you will only be able to see the 'C' characters along with some string getting printed on console.

    In OSPI boot mode, you will be able to see the output from flashed application.

    Please let me know if you observe anything different from what is explained above.

    Regards,

    Tushar