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Trouble with internal pull ups on i.mx6

Question asked by Adam Garrison on Mar 25, 2015
Latest reply on Mar 25, 2015 by Adam Garrison

I’m seeing odd behavior with the internal pull-ups on the i.mx6.

 

When I configure a GPIO as in input and enable the pull-up, it yanks the input very strongly high.  If I tie a 100k pull-down externally, it doesn’t change the voltage at the input.  If I tie the input directly to ground, it sources ~95mA.  I’m positive it’s not configured as an output.  If I disable the pull-up through a register write, it no-longer does this behavior.

 

Any suggestions on what could be causing this?

 

FYI,

The particular register I’m using to control the pull-up is IOMUXC_SW_PAD_CTL_PAD_EIM_ADDR21.

 

I have it configured as a GPIO2_17 through the MUX_MODE bits in IOMUXC_SW_MUX_CTL_PAD_EIM_ADDR21

 

I have bit 17 in GPIOx_GDIR cleared (where x = 2).

 

Thank you,

Adam

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