- First, a smoke test. This is where I plug in the power and check the outputs of the several voltages on board. If it fails (because of bad design, solder issue or something else), you know because it releases the magic smoke 😅Apr 14, 2025 14:06
- Fortunately there are no issues: 5.11V on the 5V output 3.32V on the 3.3V output 0.904V on the 0.9V output And the power LED lights up! In total, with the board powered but no code running we are consuming 27mA @ 6V input, or about 150mW
- The next test: check the default vendor bootloader. I installed the sunxi-fel tool from source. On Mac, it required a `brew install libusb dtc` then `make tools` built all of the host-side binaries without issue. github.com/linux-sunxi/...
- I plugged in USB-C to my computer, ran `./sunxi-fel --list`, and.... Nothing 😅 No USB device is showing up, so I guess that means I have some hardware debugging to do
- I think it comes down to one of several possibilities: - The reset pin is pulled low - The crystal oscillator load caps have the wrong value - The ESD diodes are interfering with the USB signal I'm thinking either option 1 or 2, because 27mA current draw seems low, even for the processor at idle
