Model B V 1.1.
SoC: BMC2836
Model B V 1.2.
SoC: BCM2837
Serial from cat /proc/cpuinfo: 00000000c77ddb77
Some key specs:
  • SoC:
    • name: RP2040. Custom designed by Raspberry Pi Foundation, likely the first they make themselves rather than using a Broadcom chip. But the design still is closed source, likely wouldn't be easy to open source due to the usage of closed proprietary IP like the ARM
    • dual core ARM Cortex-M0+
    • frequency: 2 kHz to 133 MHz, 125 MHz by default
    • memory: 264KB on-chip SRAM
  • GPIO voltage: 3.3V
Figure 1. Source.
Has Serial wire debug debug. Why would you ever get one without unless you are a clueless newbie like Ciro Santilli?!?!
You can connect form an Ubuntu 22.04 host as:
screen /dev/ttyACM0 115200
When in screen, you can Ctrl + C to kill main.py, and then execution stops and you are left in a Python shell. From there:
  • Ctrl + D: reboots
  • Ctrl + A K: kills the GNU screen window. Execution continues normally
but be aware of: Raspberry Pi Pico W freezes a few seconds after after screen disconnects from UART.
The first/only way Ciro could find was with ampy: stackoverflow.com/questions/74150782/how-to-run-a-micropython-host-script-file-on-the-raspbery-pi-pico-from-the-host/74150783#74150783 That just worked and it worked perfectly!
python3 -m pip install --user adafruit-ampy
ampy --port /dev/ttyACM0 run blink.py
TODO: possible with rshell?
Install on Ubuntu 22.04:
python3 -m pip install --user adafruit-ampy
Ctrl + X. Documented by running help repl from the main shell.
Our examples at: rpi-pico-w/upython.
The examples can be run as described at Program Raspberry Pi Pico W with MicroPython.
Ubuntu 22.04 build just worked, nice! Much feels much cleaner than the Micro Bit C setup:
sudo apt install cmake gcc-arm-none-eabi libnewlib-arm-none-eabi libstdc++-arm-none-eabi-newlib

git clone https://github.com/raspberrypi/pico-sdk
cd pico-sdk
git checkout 2e6142b15b8a75c1227dd3edbe839193b2bf9041
cd ..

git clone https://github.com/raspberrypi/pico-examples
cd pico-examples
git checkout a7ad17156bf60842ee55c8f86cd39e9cd7427c1d
cd ..

export PICO_SDK_PATH="$(pwd)/pico-sdk"
cd pico-exampes
mkdir build
cd build
# Board selection.
# https://www.raspberrypi.com/documentation/microcontrollers/c_sdk.html also says you can give wifi ID and password here for W.
cmake -DPICO_BOARD=pico_w ..
make -j
Then we install the programs just like any other UF2 but plugging it in with BOOTSEL pressed and copying the UF2 over, e.g.:
cp pico_w/blink/picow_blink.uf2 /media/$USER/RPI-RP2/
Note that there is a separate example for the W and non W LED, for non-W it is:
cp blink/blink.uf2 /media/$USER/RPI-RP2/
Also tested the UART over USB example:
cp hello_world/usb/hello_usb.uf2 /media/$USER/RPI-RP2/
You can then see the UART messages with:
screen /dev/ttyACM0 115200
TODO understand the proper debug setup, and a flash setup that doesn't require us to plug out and replug the thing every two seconds. www.electronicshub.org/programming-raspberry-pi-pico-with-swd/ appears to describe it, with SWD to do both debug and flash. To do it, you seem need another board with GPIO, e.g. a Raspberry Pi, the laptop alone is not enough.