found the solution for now: opkg update opkg install kmod-sdhci-mt7620 now i have another module listed: mtk_sd sd-cards are detected properly

@eblasband Here is the unit I use on my boards https://www.digikey.com.au/products/en?keywords=1276-6687-1-ND

@György-Farkas Thank you!

@Chris-Morgan said in Where can I find the Omega2+ schematics (model: OM-O2P)?: That's the same url I posted above Yes. As you know the Onion Omega2+ is (only a little bit more than two (2) year old device. So I just drew your attention to this important info: Updates will occur on a regular basis, stay tuned! / @Lazar-Demin/

@György-Farkas Thanks a bunch! I was stuck as I didn't have an oscilloscope at the time. I ordered one right away and received it the following week. Your response was already in hand. I "knew" there was the incompatibility as I knew (absolutely) the O2+ 3.3V system and many years of RS-232. However I couldn't find any specifics in the Omega docs of the actual device interface. Your answer confirmed what I knew. However your answer was much better as it provided a candidate solution to the incompatibility. thanks!! Bill

the docs for the MT7688 are pretty light for a MPU I would suspect that Mediatek thinks of it not as an MPU, but an SoC designed to be a wifi router or a few related types of media boxes. Crystals typically have two closely spaced but distinct resonances, and are intended and specified for use at one or the other in compatible type of circuit. The "Xin/Xout" style would likely be operating in a series resonance mode, while the one side grounded would be operating in parallel one. To get an accurate frequency you would need one cut for the resonance mode intended to be used. If you are designing your own board at more than "see if I can" level you probably need to be in contact with Mediatek - not only for details, but to arrange a supply of chips. For an experiment, just transplant the crystal along with the chip.

https://community.onion.io/topic/1524/would-someone-clarify-the-exact-function-of-these-omega2-pins/

Well, well, well look what we have here....... Thank you @WereCatf

@youlian-troyanov you're not missing anything. The confusion is in the specifics of my design. I using the Omega mini dock and powering the unit through it's mini USB port (5 vdc) eliminating a lot of custom wiring, cabling or converters :slight_smile:

Just noticed there is a new Wiki page (https://wiki.onion.io/Hardware-Specifications/Electrical-Characteristics) that has basic electrical specs for the GPIO pins and a link to the PDF file for the AR9331 as above. Note in particular that the AR9331 PDF document contains additional information relating to electrical specs in section 7 on page 305 Thanks to the Omega people for this - much appreciated

@Zheng-Han This makes a bit more sense. However: I note that the picture of the physical switch actually shows a fifth solder connection - between 1 & 2 in your picture - and I observe that this is soldered on my Expansion Dock I still don't understand just how this all works and how the switch is actually connected. @Lazar-Demin above says that the RESET_BTN is connected to ground when the button is NOT depressed. I still don't see how this works given the circuit diagram and your description of the button

@ramon-schepers Do you made the onion as part for eagle byself? If yes, can you share it? Or can I find the lib for eagle somewhere? If yes, where? I want to use for my own board. Thanks Ulrich

@Kit-Bishop No problem at all I wish we had more time and resources so we can get all the documentation and tutorials up for you guys.