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General • Re: Battery-Powered Pico W and USB Type-C Connection Issue

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Can you measure VBUS on the Pico (W) pin? I am quite curious about what voltage is going into the CYW43439 GPIO pin. If I am using such a board, I wouldn't be able to get myself to depend on a high logic level of 2.3V (for my case of VBUS 4.6V) when VIH(min) is spec'ed at 2.0V. I think a Schmitt trigger would be best for that kind of input signal, but the CYW43439 DS does not provide such details. Suppose it is a rise time problem, then perhaps the rise time can be improved by holding down the GPIO and then releasing it occasionally to check for VBUS.
Thanks, The voltages on pins 40 (VBUS) and 38 (GND) of the Pico and Pico W were measured with a multimeter.

Standard Pico's case.
Power supplied VSYS and USB cable disconnected:
0.42V
Power supplied VSYS, USB cable connected to Pico and finally to host:
5.17V
Power supplied VSYS, USB cable connected to host and finally to Pico:
5.17V

Pico W's case.
Power supplied VSYS and USB cable disconnected:
1.36 V
Power supplied VSYS, USB cable connected to Pico W and finally to host:
0.97..1.09V (Multimeter readings are not stable)
Power supplied VSYS, USB cable connected to host and finally to Pico W:
5.16V

If I want to directly measure what voltage is input to WL_GPIO 2 of CYW43439, I need to open the shield... I'm stumped.

Statistics: Posted by 0yama — Wed May 08, 2024 6:19 am



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