Pull up/down on GPIO

I cannot setup the GPIO Input Digital with a pull down / pull up or none. The setting doesn’t appear on UI.


FX30S Octave - Firmware 3.1.0
Romuald

Hi,

The IO pins on the rear panel of the FX30 operate differently than those on the IoT slot. The IO1, 2, 3 pins are buffered and protected. They use separate GPIO to control the pull resistors. In the case of IO2, the signal which controls the pull up is EXT_IO2_PU.

This is documented in the FX30 user guide :
https://source.sierrawireless.com/-/media/support_downloads/airlink/fastrack/41110030_fx30-user-guide_r6.ashx

Thanks,
Ian

Thank you for your answer.

The documentation said that a pull up is connected to the GPIO when EXT_IO2_PU = false.

Could you confirm when the EXT_IO2_PU is true, a internal pull down is connected to the GPIO ?
Thank you,

Romuald

Hi Romuald,

I can confirm that setting EXT_IO2_PU to true will enable the pull up on IO2. This is in line with with Table D-1 or the FX30 User Guide, where the corresponding GPIO must be high (asserted) to enble the pull up.

Where did you see the documentation which says “pull up is connected to the GPIO when EXT_IO2_PU = false” ? We will correct it.

Thanks,
Ian

Hi Ian,

Sorry, I was wrong.

My configuration is :
I didn’t connect anything on IO2.
When I set EXT_IO2_PU to true (pull up), I detect a false value on EXT_IO2_DI.
When I set EXT_IO2_PU to false, I detect a true value on EXT_IO2_DI : is the GPIO connected internally to the ground via a pull down ? If yes, what’s is the impedance of the pull down ?

Thanks,
Romuald

Hi Romuald,

Yes. There is an internal pull down network on the input of IO2. Please see the attached sketch.

Thanks,
Ian

Thank you Ian for your detailed answer.