morganFew things are worse than bugs that just don't make sense. I went over and over my schematic, I went over the CP2102N Errata, I went over my soldering and simply nothing was wrong. And after building up my second board (and most of a third) to get the same issue I was getting really frustrated.
One thing I hadn't tried was..... another computer. So the phantom USB issue I've been battling for weeks was actually an issue with my desktop. Fuuuuuuuuun.
The good news here is that I'm now not in a rush for a second revision. The only major changed planned was breaking out the few remaining pins. So as is, these will be acceptable for being deployed as relay nodes but until another revision is done additional sensors won't be possible. This is great!
The last remaining test I have is the battery charge circuit. Though I'm not sure if this will get used as I'm likely going to power these early nodes from an OrangePi Zero USB port that will be powered from LiFePO4 batteries charged by a #LiFePO4wered/Solar1 module.
Look at that! Three of them and they all work! Hopefully the next update will be these, in enclosures with antennas and everything! woot!
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I'd love to, but at 6-12 Mb/s download and 3 in upload depending on weather. Mts. Noire, S W France! Beautiful calm.... laughable internet. Love it here!
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Hooray, glad you got this working better!
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Yyyyeah, it's still not ideal and I've identified another problem. The lack of pull-down resistors on the LoRa reset line is causing SPI and driver init issues. I cannot think of a solid reason this would contribute to the boot issue though.
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Could it be that IO12 isn't reliably pulled low during ESP32 boot? Sorry if that's what you are saying already.![]()
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I was not suggesting that, but it was also on my mind as the only (albeit unlikely) thing I can think of. This would mean the SX1276 fires off random interrupts on boot, which feel unlikely. I'm going to test this theory this afternoon on a different board.
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Bah! I popped a 1k pull-down resistor on IO12 but the USB still isn't resetting. Really at a loss to what's going on.
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Any use for a comparison and confirmation of the signal logic needed? https://forums.adafruit.com/viewtopic.php?f=8&t=167333
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oh! OOOooooh! I'm using N-Channel MOSFETs when the design calls for using NPN Transistors.
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Does this mean rev 2 is a higher priority than anticipated? Or can you fix the boards you have?
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I just don't even know at this point. I replaced the MOSFETs with NPN transistors and it still behaves the same. And with some suggestions from @Patrick Van Oosterwijck (thanks) I dug a bit further to test wether the ESP32 is booting after the flash... and it is. This solidly puts the blame on the CP2102N as I suspect.
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