Reset GPIO & Serial on Original Omega2+...
I have a very old Omega2+...probably first rev or thereabouts. It mostly works, and the pins mostly line up with the current pinout diagrams, but on a MiniDock (also probably first rev) the Reset GPIO and the UART Rx pins are messed up.
Using the USB-UART chip on the MiniDock, I can see boot messages, but I can't type anything. If I use a separate TTL USB cable connected to RX0/TX0 (GPIO12-13) I can talk to the Omega2+ (the same output goes through the USB-UART chip too.)
And my current critical problem: the reset button on the MiniDock is not recognized during the UBoot startup. (I broke my kernel so I need to do a USB re-flash, but I can't interrupt the boot process to tell it to do that.) I've also tried grounding the FW-RST pin (GPIO38, right next to TX0) but that doesn't do it either.
I know this Omega2+ can be boot-interrupted because I have a Power Dock that does it, but I'm on a biz trip and only have the MiniDock with me. So I need to find a pinout of the early Omega2+ to figure out which pin to ground to interrupt the boot process.
Got it! FW-RST/GPIO38 is active HIGH! I had just enough jumpers to hook up my separate UART-TX so I could type, and also pull FW-RST high during boot. I'm flashing omega2.bin from USB right now, and will be able to get my own (fixed!) firmware installed shortly. Phew!
@Dave-M The hardware design guide is very helpful in designing these circuits.
https://github.com/OnionIoT/Omega2/blob/master/Documents/Omega2S Hardware Design Guide.pdf
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