5 Replies Latest reply: Oct 31, 2011 1:30 PM by Don Don RSS

additional serial port on iMX25PDK

aditya gawand Level 1

Hello Everyone,

 

I need to know how to access the additional serial port on iMX25PDK (personality board). There is a male DB9 connector given on the main personality board. I am guessing it is the "/dev/ttymxc1" port. The "/dev/ttymxc0" is on the debug board which is being used for console. I need a serial port other than console. I tried "cat /dev/ttymxc1" on the console, shorted the rx-tx to see if what I type is reflected, but nothing comes.

I have also written a program to open and write the serial port using termios , it is successfully opening and wrtiting it, but nothing comes on the actual hardware. I have tested this program on ubuntu desktop, and it works perfectly. Is there any jumper setting I am not aware of ? ALso, I know the iMX25 has 5 UARTs, is there any way to bring them out on the board if possible ?

 

Thanks,

Aditya
  • Re: additional serial port on iMX25PDK
    Fabio Estevam Employee

    If you are using a mainline kernel you should register the serial port as follows:

    imx25_add_imx_uartX(&uart_pdata);  (where X is 0 for UART1, 1 for UART2, etc).

     

    If you are using a FSL kernel, then you need to open arch/arm/mach-mx25/serial.c and make sure that

    UART3_ENABLED is enabled (supposing you want to enable UART3 in this example).

     

    Regards,

     

    Fabio Estevam

  • Re: additional serial port on iMX25PDK
    aditya gawand Level 1

    ok, got it.

    But the question is that how do I bring them out for access. Because, the only serial port is on debug board, which is my shell console. The male DB9 connector is a CAN device (found out from the schematics.

    There is another DB9 connector footprint on the debug board, but no actual connector. Now I am starting to think that _this_ is the /dev/ttymxc1 device, and not the one on main board. Also I have observed that the iMX25PDK will not boot without the debug board, is this supposed to happen ?

    Anyway, I am working on it, will post a solution when I find it. Thanks for the reply Fabio,...appreciate it.

  • Re: additional serial port on iMX25PDK
    Fabio Estevam Employee

    MX25PDK can boot without the debug board. In order to do so you need to pass “remove_dbg" into the kernel command line.

     

    This is documented in the MX25 Linux Release Notes document.

     

    Regards,

     

    Fabio Estevam

  • Re: additional serial port on iMX25PDK
    aditya gawand Level 1

    Damn it, don't know how did I miss that.

    Thanks a lot man...

    But how do I get a console on the main  then. Because only CAN is available on the main board, no UART. I also need to bring out another serial port for my serial peripheral.

  • Re: additional serial port on iMX25PDK
    Don Don Level 1
    I think some people have had luck with CN13 on the personality board, but you will need a ribbon cable, etc to get to the that UART.