zephyr

zephyr

A Zephyr shell for SiliconRig boards, so a session can start on something interactive. Flash one and the board answers:

srig:~$ kernel version
Zephyr version 4.4.2
srig:~$ hwinfo devid
Length: 12
ID: 0x3839333133335117003e0019
srig:~$ device list
- serial@40004400 (READY)
  DT node labels: usart2

hwinfo devid returns the same chip id the demo shell prints, read off the silicon rather than compiled in.

Build

./build.sh setup     # west workspace plus the Zephyr SDK, several GB, once
./build.sh

board type	image	Zephyr board
stm32-h753	zephyr-stm32-h753.bin	nucleo_h753zi
stm32-f446	zephyr-stm32-f446.bin	nucleo_f446re
esp32-s3	zephyr-esp32-s3.bin	esp32s3_devkitc/esp32s3/procpu

The app is app/: prj.conf turns on the shell and the kernel, device and hwinfo commands, and main is empty because the shell runs on its own.

Why there is no rp2350 image yet

Two things stand between Zephyr and the Pico, and the second one is a hazard:

• Its console would have to be USB CDC, since Zephyr defaults to UART0 on pins nothing is wired to. The cdc-acm-console snippet covers that.
• Wiping the board at the end of a session needs a way back into BOOTSEL. picotool erase -f speaks a pico-sdk mechanism Zephyr does not implement, and the 1200 baud touch only works if the firmware acts on it. Zephyr can get there, CONFIG_RPI_PICO_ROM_BOOTLOADER plus the rp2-boot-mode-retention snippet plus a watcher on the CDC line rate, but until that is built and proven, flashing a Zephyr image to the Pico would leave a board that only physical access can recover.