rp2040 internal GPIO pullup/pulldown resistors

[midnightelf]

I have searched through the rp2040 datasheet (dated 2021-06-23) and I cannot find any mention of the values of the GPIO pullup/pulldown resistors. I note there are some resistor values mentioned for the USB interface, I'm *not* referring to those.

Could the RP2040 designers either point me at the doc reference that I've missed and or please let me know the values (and mark it for inclusion in future manuals).

thanks muchly

[Milliways]

I have searched through the rp2040 datasheet (dated 2021-06-23) and I cannot find any mention of the values of the GPIO pullup/pulldown resistors. I note there are some resistor values mentioned for the USB interface, I'm *not* referring to those.

Could the RP2040 designers either point me at the doc reference that I've missed and or please let me know the values (and mark it for inclusion in future manuals).

thanks muchly

If you are relying on the value of pullup resistors you are doing the wrong thing. They are OK for pulling unconnected GPIO to HIGH, but the actual value varies.

If you are REALLY interested it is simple to measure; connect a 50kΩ resistor to ground then measure the voltage, and a simple calculation will give you the value.

[yeahimthatguy]

It is in the datasheet, page 634

min|max

[midnightelf]

@milliways - sure I can measure a sample of one, but that's not the same as being told what the design spec/range is. I think most other EE product designers would want to know the expected values/range to ensure a product design is well thought out. The resistors are there to be used and "relied upon" within appropriate limits.

@yeahimthatguy - thanks! I searched for "pullup" and "resister" as those terms are used elsewhere in the text, but I didn't search for "pull-up" or "resistance" !

[jamesh]

We already have an issue to fix up inconsistent use of pull-up in the docs. https://github.com/raspberrypi/pico-feedback/issues/70