Pico Zephyr Project

This repo contains setup instructions and example for working with Zephyr on the Raspberry Pi Pico and Pico 2 boards.

The aim is to make it easy to get set up and going, with examples that point towards more complex applications.

Instructions

Installation

From a blank Raspberry Pi image, open a terminal, create a folder and go into it:

mkdir dev
cd dev

Clone this repository:

git clone https://github.com/raspberrypi/pico-zephyr.git

Run the setup script:

cd pico-zephyr
./scripts/minimal_setup.sh

This command will take a few minutes to run, as it is downloading and installing Zephyr dependencies.

While the command is running, plug your Pico board in via the Debug Probe:

Building and Flashing

Command Line

When the installation has finished, build the example image for your Pico:

# For Pico H and Pico WH using RP2040:
build_rp2040.sh
# For Pico 2 and Pico 2W using RP2350:
build_rp2350.sh

By default, this will use the UART serial port. To use the USB serial port which also powers the Pico, add usb_serial_port when building:

# For Pico H and Pico WH using RP2040:
build_rp2040.sh usb_serial_port
# For Pico 2 and Pico 2W using RP2350:
build_rp2350.sh usb_serial_port

Note that when switching between UART and USB serial, it may be necessary to delete the build directory for this change to take effect.

Flash the Pico:

. .venv/bin/activate
west flash

VSCode

Install VSCode with:

./scripts/vscode_setup.sh

This will install VSCode and the Cortex-Debug extension.

Open this folder in VSCode. You can run code . from the command line.

To build, press Ctrl+Shift+B and select either Zephyr Build RP2040 or Zephyr Build RP2350 for the chip you are targetting. Select app. Select between the UART or USB for serial output. Note that when switching between UART and USB serial, it may be necessary to delete the build directory for this change to take effect. Press Enter to confirm the OpenOCD path or change it to the directory where OpenOCD is installed.

To flash, press Ctrl+Shift+B and select Zephyr Flash.

View Output

View the output via serial port with:

minicom -D /dev/ttyACM0

You may need to change /dev/ttyACM0 to another value depending on the serial port the Debug Probe is recognised on. When the USB serial port is in use, it will may be found on a /dev/ttyACM1. Find the port using ls /dev/tty* while plugging and unplugging the debug probe or Pico board to see which values change.

Debugging

Command Line

Debug with gdb:

west debug
...
(gdb) break main
(gdb) run
Thread 1 "rp2350.dap.core0" hit Breakpoint 1, main () at /home/user/dev/pico-zephyr/app/src/main.c:8
8               printk("Zephyr Example Application for Pico\n");
(gdb) n
11                      printk("Running on %s...\n", CONFIG_BOARD);
(gdb) n
13                      k_sleep(K_MSEC(1000));
(gdb) n
10              while (1) {
(gdb) n
11                      printk("Running on %s...\n", CONFIG_BOARD);
(gdb) n
13                      k_sleep(K_MSEC(1000));
(gdb) n

VSCode

Install VSCode with:

./scripts/vscode_setup.sh

This will install VSCode and the Cortex-Debug extension.

Open this folder in VSCode. You can run code . from the command line.

To debug, press Ctrl+Shift+D to open the Run and Debug pane.

At the top, next to the Start Debugging button, you can select RP2040 Debug (Zephyr) or RP2350 Debug (Zephyr) for the chip you are targetting. Press Enter to confirm the OpenOCD path or change it to the directory where OpenOCD is installed.

VSCode will then enter the debugging view starting in main, where you can step over each instruction and inspect the source code. Further debugging instructions can be found here.

More Examples

Wifi Example

The wifi_example connects to a Wi-Fi network, pings 8.8.8.8, and performs HTTP GET and POST requests with JSON.

To begin, create a file in wifi_example/src/ called wifi_info.h and add the SSID and PSK for the Wi-Fi network:

Caution

NEVER COMMIT OR SHARE THIS FILE PUBLICLY - This could be a big security issue and is for demonstration purposes only

// wifi_example/src/wifi_info.h
#define WIFI_SSID "MySSID"
#define WIFI_PSK  "my_password"

Then build (currently only supports Pico W):

./build_rp2040_w.sh wifi_example

Or to build using VSCode, press Ctrl+Shift+B and select Zephyr Build RP2040_W, then enter wifi_example for the application option before continuing with the other steps.