Undocumented: Fastrack XTreme GPIO Current Ratings?


#1

Like the Supreme before it, the Xtreme has two GPIOs available in the Molex Microfit connector.

Unlike the Supreme, the voltage range of these is controlled by Vref (15V max).

But I can’t see anything in the User Guide that says what the current capability of these pins is :question:


#2

Supplementary question:

Is Vref purely a reference, or does it also have to supply any current sourced by the GPIOs?


#3

My understanding is the GPIO’s on the power connector are open drain and Vref is the pull for the open drain.


#4

Thanks - but where did you gain that understanding?
I haven’t seen it documented any where. :angry:

Do you know what the pullup value is?

Or the current rating (sink) of the drivers?


#5

Note that this is still undocumented in Rev 2 of the User Guide. :angry:

My understanding is that they aren’t - there is an active voltage level translator between the pins of the Q26 and the pins of the Molex connector.


#6

This appears to have been addressed in Rev-003 of the guide:

WA_DEV_FEX20_UGD_002
003
October 12, 2010

Note that the pin assignments are confused: https://forum.sierrawireless.com/t/airlink-fxt-series-user-guide-gpio-pins/4921/1