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Problem reading GPIO 99/100

Andreas Naumann
Prodigy 80 points

Hi, I'm trying to read form GPIO 99, 100 and 101. I have configured the Padconf accordingly (Inputenable=1, Mux=4), but only GPIO101 works as expected. On 99 and 100 I always read 1 even when I measure 0.0 Volts on the line... Do you have any suggestions regarding this? Thanks.

 

best regards, Andi

  • 0
    Expert 1130 points

    Hello,

    Check PINMUX register's configuration. You need to have 0x8 in correesponding bit field in order to use it as GPIO.

    Regards
    Arye

    P.S. I am not sure that reading a certain pin value is a good indication for correct pin configuration.

     Oh, there is also an issue with KICK registers:

        sysRegs->KICK0R = KICK0_ENABLE_KEY;
        sysRegs->KICK1R = KICK1_ENABLE_KEY;   

    You have to enable them. You can find it in PSPIOM GPIO example.

  • 0
    Intellectual 270 points

    Andi

    GPIO 99 and 100 (and also 112-115) are powered off the VDDS_CSI2 power input to the processor.  You should check to make sure the power rail that feeds that pin is turned on.  This is a different power rail than feeds GPIO 101, so that is why 101 works.

    Nate

  • 0 in reply to Nathan Kro
    Prodigy 80 points

    Hi Nathan and Arye, thanks for your replies! I measured the VDDS_CSI2 and it is OFF. As to turn it on, I have to figure out the way to command the twl4030 to do it for me. Or is that what Arye is suggesting with

    sysRegs->KICK0R = KICK0_ENABLE_KEY;
    sysRegs->KICK1R = KICK1_ENABLE_KEY;

    ? Doesnt really sound like it...

     

    regards, Andi

     

     

  • 0 in reply to Andreas Naumann
    Prodigy 40 points

    gpio_99  gpio_100 cam_d0 cam_d1

     

    Adding the signal names as listed in the docs in hopes that the next guy won't google as long as I did!