1. If Edison is OFF and +5V USB is plugged in. That will turn ON Q1.1 and turn OFF Q2.1 resulting in logic high for PWRBTN# on Edison. Basically that will do nothing for Edison and it will stay OFF.
2. Note that since the Edison module is OFF, the gate of p-channel FET Q1.2 is 0 volts and the pin 2 of R4 is at VBAT while pin 1 of R4 is ground because Q1.1 is ON.
3. Now removing the +5V USB will make the gate of Q2.1 to VBAT thereby turning it ON. This will pull down PWRBTN# pin on Edison module.
4. Once Edison is turned on, net V3P3_Edison will become 3.3V turning OFF p-channel FET Q1.2. This will lead to the gate of Q2.1 pull down to GND by R5. This will bring back the PWRBTN# of Edison high.
5. Note that once Edison is turned on, if you insert +5V USB, nothing will happen.
Adafruit publishes a wide range of writing and video content, including interviews and reporting on the maker market and the wider technology world. Our standards page is intended as a guide to best practices that Adafruit uses, as well as an outline of the ethical standards Adafruit aspires to. While Adafruit is not an independent journalistic institution, Adafruit strives to be a fair, informative, and positive voice within the community – check it out here: adafruit.com/editorialstandards
Stop breadboarding and soldering – start making immediately! Adafruit’s Circuit Playground is jam-packed with LEDs, sensors, buttons, alligator clip pads and more. Build projects with Circuit Playground in a few minutes with the drag-and-drop MakeCode programming site, learn computer science using the CS Discoveries class on code.org, jump into CircuitPython to learn Python and hardware together, TinyGO, or even use the Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for CircuitPython, MakeCode, and Arduino. It has a powerful processor, 10 NeoPixels, mini speaker, InfraRed receive and transmit, two buttons, a switch, 14 alligator clip pads, and lots of sensors: capacitive touch, IR proximity, temperature, light, motion and sound. A whole wide world of electronics and coding is waiting for you, and it fits in the palm of your hand.
Have an amazing project to share? The Electronics Show and Tell is every Wednesday at 7:30pm ET! To join, head over to YouTube and check out the show’s live chat and our Discord!
Python for Microcontrollers – Adafruit Daily — Python on Microcontrollers Newsletter: CircuitPython 2025 Wraps, Focus on Using Python, Open Source and More! #CircuitPython #Python #micropython @ThePSF @Raspberry_Pi
EYE on NPI – Adafruit Daily — EYE on NPI Maxim’s Himalaya uSLIC Step-Down Power Module #EyeOnNPI @maximintegrated @digikey
