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Dm8148 uart prompt "CCCC" not coming

debasish saha1
Intellectual 920 points

Hi ,


I am using a DM8148 custom board. The serial port of the custom board is connected to my PC. On power on I was expecting to see "CCCC" in my teraterm console. But nothing is coming. The settings of my teraterm console is as :

    Baud rate: 115,200
    Data bits: 8
   Parity: None
  Stop bits: 1
  Flow control: None

Please can you tell me why I am not getting "CCCC" in teraterm window?

Regards,
Debasish
  • 0
    TI__Guru**** 170625 points

    Hi Debasish,

    I am getting "CCCCCC" in the terminal window when I set the DM814x board for UART boot. So, did you set your sysboot pins for UART boot? If not, can you try that.

    Regards,
    Pavel

  • 0
    TI__Guru**** 170625 points

    Debasish,

    debasish saha1 said:
    I am using a DM8148 custom board.

    Are you using the same UART (UART0) for console as the DM814x EVM?

    If you are using different UART for console (different than UART0), refer to the below wiki page:

    http://processors.wiki.ti.com/index.php/TI81xx_PSP_Porting_Guide#Using_different_UART_than_the_default_EVM_configuration_as_console

    Best regards,
    Pavel

  • 0 in reply to Pavel Botev
    TI__Guru**** 170625 points

    Debasish,

    I could be also HW related issue, see the below e2e threads:

    http://e2e.ti.com/support/arm/sitara_arm/f/791/t/189506.aspx

    http://e2e.ti.com/support/arm/sitara_arm/f/791/t/195856.aspx

    http://e2e.ti.com/support/arm/sitara_arm/f/791/t/231011.aspx

    http://processors.wiki.ti.com/index.php/AM335x_board_bringup_tips#Is_the_device_alive

    If you have gone through the power sequencing check list above, there are a couple of things to try:

    • If you connect a UART cable to your debug port (which should be connected to UART0), you should see a steady stream of 'C' characters output on a terminal window (such as Teraterm). This means that the ROM is executing and is attempting to boot. If you see this you can move on to the next section. Note that you will only see this output if UART0 in in your boot sequence. If you don't have the ability to change the boot sequence, then try the JTAG method below.
    • If you don't see the 'C' output with UART0 in the boot sequence, you may have something wrong with your device. However, you may have an issue with the UART0 data path, or you may have a bad cable. Probe the UART0_TXD signal and see if you observe any toggling on the signal. If you do, there is most likely a problem with your UART transceiver or cable.

    Best regards,
    Pavel

  • 0 in reply to Pavel Botev
    Genius 3700 points

    Hi,

         Try with a serial crossover cable,

    -David

  • 0 in reply to David Soto - RidgeRun
    Intellectual 920 points

    Hi,

    I think the issue was with the boot mode pins. Changing the boot mode to UART first, I am getting the "CCCC" transmission in my serial port. Previous booting mode was for SPI first. Thanks all for your support.

    Regards,

    Debasish