I am looking at the Pico 2 power chain circuit diagram in Section 5.4 on page 16 of https://datasheets.raspberrypi.com/pico ... asheet.pdf
Am I correct in assuming that if I am not using the mico-USB connector as the power source then I could simply treat GPIO24 as a digital input and detect a 5v signal that is active-low? I am asking here because in all the discussions I've seen on squeezing extra GPIOs from a Pico (e.g. https://www.reddit.com/r/raspberry_pi/c ... y_pi_pico/ and https://www.hackster.io/news/this-raspb ... e23753281b ) I have not seen this mentioned as a possibility, even though it doesn't actually involve any soldering/desoldering/trace cutting: the signal is just sitting there on pin 40. The only trouble is that is goes through a voltage divider, so it doesn't behave the same way as a regular GPIO, certainly not for output, but for detecting active-low signals it should work, shouldn't it? (Yes, I am going to try it, and I will report back here, ...)
There is a further possibility of using other pins on the USB connector as GPIO if it's not actually required for USB, but that involves patching leads from TP2 and TP3. There is also TP5 which gives you GPIO25, albeit through a 470R resistor. These require soldering, but that's not as invasive as de-soldering/trace cutting.
Am I correct in assuming that if I am not using the mico-USB connector as the power source then I could simply treat GPIO24 as a digital input and detect a 5v signal that is active-low? I am asking here because in all the discussions I've seen on squeezing extra GPIOs from a Pico (e.g. https://www.reddit.com/r/raspberry_pi/c ... y_pi_pico/ and https://www.hackster.io/news/this-raspb ... e23753281b ) I have not seen this mentioned as a possibility, even though it doesn't actually involve any soldering/desoldering/trace cutting: the signal is just sitting there on pin 40. The only trouble is that is goes through a voltage divider, so it doesn't behave the same way as a regular GPIO, certainly not for output, but for detecting active-low signals it should work, shouldn't it? (Yes, I am going to try it, and I will report back here, ...)
There is a further possibility of using other pins on the USB connector as GPIO if it's not actually required for USB, but that involves patching leads from TP2 and TP3. There is also TP5 which gives you GPIO25, albeit through a 470R resistor. These require soldering, but that's not as invasive as de-soldering/trace cutting.
Statistics: Posted by ianangrant — Sun Jun 29, 2025 3:25 pm — Replies 2 — Views 98