Power on the microusb port
So I am doing an octopi setup with a Pi Zero W. I know this is not the ideal board for OctoPi. But I am not using any camera functionality, and I already have it setup on the Zero and it works fine for remote printing.
My hope with this setup was to just have a single cable going to the Pi, backfeeding power in though the Zero's USB data port to eliminate extra cabling, another power brick for the Pi or using another USB cable to take power from the USB A port on the Mini. Also still keeping it free for USB thumbdrive printing. Yes backfeeding power though the Zero's data USB port does work and you can find info about it on the internet, and I have already successfully powered my Zero though the USB data port.
The issue I have discovered is that the microusb port on the Mini does not supply power. When the Zero is plugged into that port with the short microusb male to male OTG cable that I have it will not power up. Also confirmed no power with another microusb to USB A OTG cable and plugging a USB power meter in.
Looking at the USB section, Pg10 of the schematic https://github.com/prusa3d/Buddy-board-MINI-PCB/blob/master/rev.1.0.0/BUDDY_v1.0.0.pdf I see that there is a JP1 that ties the microusb +5v line to +5v. Can anyone confirm that the actual purpose of JP1 is to make the microusb port powered?
So I got impatient and popped open the electronics box. I don't see a JP1 anywhere on the board. There is a J1 next to the tab you have to break for a custom firmware. My understanding is that has to be jumpered after breaking the tab for a custom firmware. The only other set of headers I see is next to the micro-controller, I assume a JTAG for programming.
Unless JP1 is some solder pads on the bottom of the board that need to be bridged? I didn't feel like pulling out all the wiring to pull out the board to look under it. Also noticed my board is a different revision than that schematic. I have 1.0.5. I can't find a schematic for that revision.
Searched all though google images and couldn't find any pictures of the bottom of the board. Tried ebay and found some listings of the clone boards with pictures of the bottom. Sure enough JP1 is a set of solder pads to be bridged on the bottom. Guess I am going to be pulling the whole thing apart now. Think I am still going to wait and see if anyone can confirm that is what those pads are for before I attempt bridging them.
So I bit the bullet and bridged the JP1 pads on the bottom of the board. It does indeed provide 5v to the Micro USB port. I have successfully powered my Pi Zero W by back feeding power though it's USB data port. So only a single connection is needed between the Mini and the Pi using a male to male OTG Micro USB cable.