It just tries to boot repeatedly with the same sequence.
The zephyr.bin file is 408 kB. It looks different to the previous files I built for the STM Swan. It is not a pure binary file and has error messages and stuff in it. I’m not sure if I’m using the correct file.
I know it’s a very old ESP32C3 chip. I am getting some more next week.
I tried flashing some basic firmware, generated using the Ardiuno IDE, with esptool. After several attempts I found that, for the ESP32C3, the address must be entered as 0x00000000. Entering it as 0x0000 or any other way does not work.
I then flashed a bin file, generated by West, with esptool. That worked with the same settings.
I tried to make a binpack using the changed address, in full, and it worked.
So, if anyone needs it, full instructions for using DTU with the Xiao ESP32C3 are:
Connect RX and TX according to the instructions.
Connect Aux4 of the Notecard to the EN pad on the bottom of the Xiao.
Connect Aux3 of the Notecard GPIO9.
Invert Aux1 of the Notecard so it provides a high output during firmware update. I used an Arduino for this exercise but will use a FET in my product. I then connected the inverted output to GPIO2 and GPIO8 using 2 x 5k resistors.
Build the binpack using:
notecard -binpack esp32 0x00000000:zephyr.bin
Replace zephyr.bin with the name of your bin file. The Arduino bin file worked too.
The documentation for ESP32 hosts on the Notecard Outboard Firmware Update page shows the address as 0x10000, which is not correct for the ESP32C3.