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AM5728: How to use vout data lines in non display setup

Jason Culver
Prodigy 40 points
Part Number: AM5728


I am using the am5728 processor module with linux and I am trying to use only a few of the vout1_dX lines to send signals to off-board devices.  I am not using the vout lines for a display, I just want to use individual lines.  I have updated mux_data.h to pull the signal high, as well as tried to update dts files to get the signal for the data lines high.  The actual signal stays lows no matter what I change.  I have checked the registers at the command line and saw they they were set to be pulled up.

How do I get the vout1_dX lines to pullup? Do I need to set the DSS a certain way to be able to control the data lines?

Thanks in advance.

Jason Culver

  • 0
    TI__Guru**** 479805 points

    Hi Jason

    " I have updated mux_data.h to pull the signal high, as well as tried to update dts files to get the signal for the data lines high"

    I did not get it, how do you put data lines to high? If you are these lines as vout1 data lines, you need to enable dss to drive those lines. 

    I think the other option is to use these pins as GPIO and then you could set the GPIO to be high to set high signal on these lines. 

    Regards,

    Brijesh

  • 0 in reply to Brijesh Jadav
    Prodigy 40 points

    Hi Brijesh,

    Thanks for your response.

    In mux_data.h I am setting the vout1_d0 pin to
    +    {VOUT1_D0, (M0 | PIN_OUTPUT_PULLUP | SLEWCONTROL | MANUAL_MODE)},    /* vout1_d0.vout1_d0 */

    Reading the register in linux outputs,

    devmem2 0x4a0035dc
    /dev/mem opened.
    Memory mapped at address 0xb6fa9000.
    Read at address  0x4A0035DC (0xb6fa95dc): 0x000A0100

    showing that the signal should be pulled up, correct?  The line is still low at this point.

    I also tried setting a dts file so the defaults were matching the above vout1_d0 changes.

    The dss is status = ok in the dtb file, is there something else I need to do to enable it to drive the line?

    I would rather use the pin as a GPIO.  What steps do I need to do to enable it that way?

    Regards,

    Jason

  • +1 in reply to Jason Culver
    TI__Guru**** 479805 points

    Hi Jason,

    It is pretty straight forward to use GPIO.

    1, Set the pinmux for this pin to be GPIO, i guess it is mode-7

    2, Use GPIO direction for this pin to be output

    3, Set the pin value to be high in the GPIO register.

    Any specific reason for setting these pins to be high?

    Regards,

    Brijesh

  • 0 in reply to Brijesh Jadav
    Prodigy 40 points

    Hi Brijesh,

    I was able to get the pin high by setting it to GPIO.  I am basically using this line a software version of a button push.

  • 0 in reply to Jason Culver
    TI__Guru**** 479805 points

    Hi Jason,

    ok, good to know.

    Please mark this thread as resolved, if your question is answered and start a new thread for new question.

    Thank you.

    Regards,

    Brijesh