Arduino-Pico

Raspberry Pi Pico Arduino core, for all RP2040 boards

This is a port of the RP2040 (Raspberry Pi Pico processor) to the Arduino ecosystem.

It uses a custom toolset with GCC 10.2 and Newlib 4.0.0, not depending on system-installed prerequisites. https://github.com/earlephilhower/pico-quick-toolchain

There is automated discovery of boards in bootloader mode, so they show up in the IDE, and the upload command works using the Microsoft UF2 tool (included).

Installing via Arduino Boards Manager

Open up the Arduino IDE and go to File->Preferences.

In the dialog that pops up, enter the following URL in the "Additional Boards Manager URLs" field:

https://github.com/earlephilhower/arduino-pico/releases/download/global/package_rp2040_index.json

Hit OK to close the dialog.

Go to Tools->Boards->Board Manager in the IDE

Type "pico" in the search box and select "Add":

Installing via GIT

To install via GIT (for latest and greatest versions):

mkdir -p ~/Arduino/hardware/pico
git clone https://github.com/earlephilhower/arduino-pico.git ~/Arduino/hardware/pico/rp2040
cd ~/Arduino/hardware/pico/rp2040
git submodule init
git submodule update
cd pico-sdk
git submodule init
git submodule update
cd ../tools
python3 ./get.py

Installing both Arduino and CMake

Tom's Hardware presented a very nice writeup on installing arduino-pico on both Windows and Linux, available at https://www.tomshardware.com/how-to/program-raspberry-pi-pico-with-arduino-ide

If you follow Les' step-by-step you will also have a fully functional CMake-based environment to build Pico apps on if you outgrow the Arduino ecosystem.

Uploading Sketches

To upload your first sketch, you will need to hold the BOOTSEL button down while plugging in the Pico to your computer. Then hit the upload button and the sketch should be transferred and start to run.

After the first upload, this should not be necessary as the arduino-pico core has auto-reset support. Select the appropriate serial port shown in the Arduino Tools->Port->Serial Port menu once (this setting will stick and does not need to be touched for multiple uploads). This selection allows the auto-reset tool to identify the proper device to reset. Them hit the upload button and your sketch should upload and run.

In some cases the Pico will encounter a hard hang and its USB port will not respond to the auto-reset request. Should this happen, just follow the initial procedure of holding the BOOTSEL button down while plugging in the Pico to enter the ROM bootloader.

Status of Port

Lots of things are working now!

• digitalWrite/Read (basic sanity tested)
• shiftIn/Out (tested using Nokia5110 https://github.com/ionpan/Nokia5110)
• SPI (tested using SdFat 2.0 https://github.com/greiman/SdFat ... note that the Pico voltage regulator can't reliably supply enough power for a SD Card so use external power, and adjust the USE_SIMPLE_LITTLE_ENDIAN define in src/sdfat.h to 0)
• analogWrite/PWM (tested using Fade.ino)
• tone/noTone (using IRQ generated waveform)
• Wire/I2C (tested using DS3231 https://github.com/rodan/ds3231)
• EEPROM (tested examples)
• USB Serial(ACM) w/automatic reboot-to-UF2 upload)
• Hardware UART
• Servo (basic waveform testing, disables/re-enables without any short pulses)
• printf (i.e. debug) output over USB serial

The RP2040 PIO state machines (SMs) are used to generate jitter-free:

• Servos
• Tones

Todo

Some major features I want to add are:

• Installable filesystem support (SD, LittleFS, etc.)
• Updated debug infrastructure
• I2S port from pico-extras

Contributing

If you want to contribute or have bugfixes, drop me a note at earlephilhower@yahoo.com or open an issue/PR here.

-Earle F. Philhower, III earlephilhower@yahoo.com