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The GPIO126 on omap37XX

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Posted by Eric Texley

on Jul 27 2012 08:00 AM

Intellectual260 points

Dear E2E Community,

I am trying to use the GPIO-126 on OMAP37XX as Pulled Up GPIO.

Various references tell me (including the TRM) tell me that “further” configuration is needed for “special” GPIOs 120-129 namely PBIASLITEPWRDNZ1 from CONTROL_PBIAS_LITE, PBIASLITEVMODE1 from CONTROL_PBIAS_LITE (to selected 1.8 or 3.0 volt swing) together with setting the GPIO_IO_PWRDNZ from CONTROL_WKUP_CNTL. { http://processors.wiki.ti.com/index.php/Additional_Configuration_for_GPIO120-129_on_OMAP35x }

I performed these initializations. But I still have a problem. Now I test the input with a meter, and I find that Pulled Up this input is only at .03 volts, and pulled down, the input is at 0.0 volts.

Another source suggests that I must draw power for these GPIOs from some other source….specifically “VIO” for the GPIOs. But where is VIO defined?

“

If the device is associated with the power IC, before using an extended-drain I/O interface, the software

must program the power IC to enable the VMMC1 (for the MMC/SD/SDIO1 module or muxed GPIO I/Os )

or VIO for (gpio126, gpio127, and gpio129 I/Os), and the LDO and to provide a 1.8-V/3.0-V voltage. This

is done by software through the inter-integrated circuit (I2C™) interface that links the device and power IC

“

Where is the input named "VIO" on the OMAP?

Regards,

Eric Texley

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Posted by Eric Texley

on Aug 02 2012 09:06 AM

Intellectual260 points

One further piece of information...this is a CUS package of OMAP 37XX which I am working with. The pin which I am MUXING for GPIO126 is "N22" Again when I change pull up/pull down on the PAD, the voltage (read with a meter) on this pad goes from .03 to 0 volts...so I am hitting the right pad.

Posted by Eric Texley

on Nov 08 2012 15:23 PM

Verified Answer

Verified by Eric Texley

Intellectual260 points

We found the answer. VDD_X. We connected it to VDD_MMC1 so GPIO126 could work