RP2040-Keyboard-3

Overview

The Waveshare 3-Key Shortcut Keyboard Development Board [1] is based on the RP2040 microcontroller from Raspberry Pi Ltd. It has three keys with the default values “CTRL”, “C” and “V”. The board is equipped with two USB type C connectors. There are two versions of the keyboard, where the diffence is in the housing (plastic or metal). This board definition can be used with both versions.

Hardware

  • Microcontroller Raspberry Pi RP2040, with a max frequency of 133 MHz

  • Dual ARM Cortex M0+ cores

  • 264 kByte SRAM

  • 2 Mbyte QSPI flash

  • 3 user keys

  • 3 RGB LEDs (Neopixels); one in each user key

  • Dual USB type C connectors (use one at a time)

  • RESET and BOOT buttons

The RESET and BOOT buttons are located on the back side of the board, on separate long edges of the board. The BOOT button is located at the long edge with a USB connector, and the RESET is located at the other long edge of the board.

Default Zephyr Peripheral Mapping

  • Button CTRL (left) : GPIO14

  • Button C (center) : GPIO13

  • Button V (right) : GPIO12

  • RGB LEDs: GPIO18

Note that no serial port pins (RX or TX) are exposed. By default this board uses USB for terminal output.

See also Waveshare P2040-Keyboard-3 wiki [2] and schematic [3].

Supported Features

The rp2040_keyboard_3 board supports the hardware features listed below.

on-chip / on-board
Feature integrated in the SoC / present on the board.
2 / 2
Number of instances that are enabled / disabled.
Click on the label to see the first instance of this feature in the board/SoC DTS files.
vnd,foo
Compatible string for the Devicetree binding matching the feature.
Click on the link to view the binding documentation.

rp2040_keyboard_3/rp2040 target

Type

Location

Description

Compatible

CPU

on-chip

ARM Cortex-M0+ CPU2

arm,cortex-m0+

ADC

on-chip

Raspberry Pi Pico ADC1

raspberrypi,pico-adc

Clock control

on-chip

Raspberry Pi Pico clock controller node1

raspberrypi,pico-clock-controller

on-chip

The representation of Raspberry Pi Pico’s clock11 2

raspberrypi,pico-clock

on-chip

The representation of Raspberry Pi Pico’s PLL2

raspberrypi,pico-pll

on-chip

The representation of Raspberry Pi Pico ring oscillator1

raspberrypi,pico-rosc

on-chip

The representation of Raspberry Pi Pico external oscillator1

raspberrypi,pico-xosc

Counter

on-chip

Raspberry Pi Pico timer1

raspberrypi,pico-timer

DMA

on-chip

Raspberry Pi Pico DMA1

raspberrypi,pico-dma

Flash controller

on-chip

Raspberry Pi Pico flash controller1

raspberrypi,pico-flash-controller

GPIO & Headers

on-chip

Raspberry Pi Pico GPIO1

raspberrypi,pico-gpio

on-chip

Raspberry Pi Pico GPIO Port1

raspberrypi,pico-gpio-port

I2C

on-chip

Raspberry Pi Pico I2C2

raspberrypi,pico-i2c

Input

on-board

Group of GPIO-bound input keys1

gpio-keys

Interrupt controller

on-chip

ARMv6-M NVIC (Nested Vectored Interrupt Controller) controller1

arm,v6m-nvic

LED strip

on-board

The pio node configured for ws28121

worldsemi,ws2812-rpi_pico-pio

Miscellaneous

on-chip

Raspberry Pi Pico PIO1 1

raspberrypi,pico-pio

MTD

on-chip

Flash node1

soc-nv-flash

on-board

Fixed partitions of a flash (or other non-volatile storage) memory1

fixed-partitions

Pin control

on-chip

Raspberry Pi Pico Pin Controller1

raspberrypi,pico-pinctrl

PWM

on-chip

Raspberry Pi Pico PWM1

raspberrypi,pico-pwm

Regulator

on-chip

Raspberry Pi Pico core supply regurator1

raspberrypi,core-supply-regulator

Reset controller

on-chip

Raspberry Pi Pico Reset Controller1

raspberrypi,pico-reset

RTC

on-chip

Raspberry Pi Pico RTC1

raspberrypi,pico-rtc

Sensors

on-chip

Raspberry Pi Pico family temperature sensor node1

raspberrypi,pico-temp

Serial controller

on-chip

Raspberry Pi Pico UART2

raspberrypi,pico-uart

SPI

on-chip

Raspberry Pi Pico SPI2

raspberrypi,pico-spi

SRAM

on-chip

Generic on-chip SRAM1

mmio-sram

Timer

on-chip

ARMv6-M System Tick1

arm,armv6m-systick

USB

on-chip

Raspberry Pi Pico USB Device Controller1

raspberrypi,pico-usbd

Watchdog

on-chip

Raspberry Pi Pico Watchdog1

raspberrypi,pico-watchdog

Programming and Debugging

The rp2040_keyboard_3 board supports the runners and associated west commands listed below.

flash debug
uf2 ✅ (default)

The board does not expose the SWDIO and SWCLK pins, so programming must be done via the USB port. Press and hold the BOOT button, and then press the RESET button, and the device will appear as a USB mass storage unit. Building your application will result in a build/zephyr/zephyr.uf2 file. Drag and drop the file to the USB mass storage unit, and the board will be reprogrammed.

For more details on programming RP2040-based boards, see Raspberry Pi Pico and especially Programming and Debugging.

Flashing

To run the LED strip sample:

# From the root of the zephyr repository
west build -b rp2040_keyboard_3 samples/drivers/led/led_strip/
west flash

Try also the Dining Philosophers, Input dump and Button samples.

Samples where text is printed only just at startup, for example Hello World, are difficult to use as the text is already printed once you connect to the newly created USB console endpoint.

To run a program that acts as a keyboard (with the keys CTRL, C and V), use the USB HID keyboard sample with some modifications. First remove the line source "boards/common/usb/Kconfig.cdc_acm_serial.defconfig" from the boards/waveshare/rp2040_keyboard_3/Kconfig.defconfig file. Then do the modifications below to the samples/subsys/usb/hid-keyboard/src/main.c file.

Change:

case INPUT_KEY_0:
    if (kb_evt.value) {
        report[KB_KEY_CODE1] = HID_KEY_NUMLOCK;
    } else {
        report[KB_KEY_CODE1] = 0;
    }

    break;
case INPUT_KEY_1:
    if (kb_evt.value) {
        report[KB_KEY_CODE2] = HID_KEY_CAPSLOCK;
    } else {
        report[KB_KEY_CODE2] = 0;
    }

    break;
case INPUT_KEY_2:
    if (kb_evt.value) {
        report[KB_KEY_CODE3] = HID_KEY_SCROLLLOCK;
    } else {
        report[KB_KEY_CODE3] = 0;
    }

    break;

to:

case INPUT_KEY_LEFTCTRL:
    if (kb_evt.value) {
        report[KB_MOD_KEY] = HID_KBD_MODIFIER_LEFT_CTRL;
    } else {
        report[KB_MOD_KEY] = 0;
    }

    break;
case INPUT_KEY_C:
    if (kb_evt.value) {
        report[KB_KEY_CODE1] = HID_KEY_C;
    } else {
        report[KB_KEY_CODE1] = 0;
    }

    break;
case INPUT_KEY_V:
    if (kb_evt.value) {
        report[KB_KEY_CODE1] = HID_KEY_V;
    } else {
        report[KB_KEY_CODE1] = 0;
    }

    break;

References