Pogo pins power clarification - reading schematics
02-14-2021, 05:20 PM
(02-14-2021, 04:21 PM)dsimic Wrote: You're right, R8 actually isn't populated in the picture of an actual PineEye board. However, the documentation or the schematic of the PineEye should provide a clear description of the resistors used as power source selectors, or anyone actually making a PineEye risks damaging their PinePhone.
Aha! So in that picture, USB-5V is used, which makes sense. DCIN would only be available when a charger is attached or when the Pinephone is acting as a USB host.
Totally agree. This should be documented clearly but doesn't seem to be. And the BOM seems to be incorrect by showing both R7 and R8 as being populated at the same time. There should be a BOM that matches the picture. Or at the very least, the BOM should explain that you pick one or the other, but not both at the same time.
I guess many people who went and actually got that PCB printed and soldered components on themselves, would figure this out. But if you follow the design blindly, it's too easy to make that mistake.
(02-14-2021, 04:21 PM)dsimic Wrote: So far, it seems that we're on the right track when it comes to decyphering the purpose of the pogo pins.
Yeah, it's encouraging to find more evidence like this that keeps building up confidence in how we're reading the schematics!
The author of the PineEye may have had the same dilemma that we did: hmm what do these pogo pins actually do, which should I use? So designed in the choice of either. And the author seems to have ultimately chosen to use the same pogo pin that I would have chosen in this case: pogo pin #5, USB-5V.
