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 difference 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.

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.

Programming and Debugging

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

	flash	debug

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;