I have a project running on a Pico W where sometimes I have a USB connection for programming/debugging with Thonny, but it is meant to run just via a power connection to Vsys. I have the dual power feeds connected more or less as described in section 4.4 of the datasheet, except that I am using a normal rectifier diode (1N4007) rather than a schottky one.
When both power feeds are conencted everything works, but with just the Vsys connection, the software starts, but then stalls.
I have various LED blink patterns set up at different stages, which indicate that boot.py runs (which could be omitted as all it does is blink to show something started), then main.py runs with its starting blink pattern showing. It then should connect to the WiFi, but the blink pattern which is triggered after that never appears.
Is the use of a non-Schottky diode likely to be the cause? I can understand that using the WiFi could increase the power requirements, but the iN4007 is a high current capable, low voltage drop diode so I don't under why that might be the cause (but neither am I an electronic engineer). Or should I be checking for problems elsewhere?
With both power connections attached or just the USB one, a voltmeter shows 5.00V on Vbus and 4.80V on Vsys. With just the Vsys power, Vsys shows 4.70V, but Vbus only 1.15V. This seems odd.
When both power feeds are conencted everything works, but with just the Vsys connection, the software starts, but then stalls.
I have various LED blink patterns set up at different stages, which indicate that boot.py runs (which could be omitted as all it does is blink to show something started), then main.py runs with its starting blink pattern showing. It then should connect to the WiFi, but the blink pattern which is triggered after that never appears.
Is the use of a non-Schottky diode likely to be the cause? I can understand that using the WiFi could increase the power requirements, but the iN4007 is a high current capable, low voltage drop diode so I don't under why that might be the cause (but neither am I an electronic engineer). Or should I be checking for problems elsewhere?
With both power connections attached or just the USB one, a voltmeter shows 5.00V on Vbus and 4.80V on Vsys. With just the Vsys power, Vsys shows 4.70V, but Vbus only 1.15V. This seems odd.
Statistics: Posted by IanS — Sat Sep 07, 2024 2:56 pm — Replies 3 — Views 72