Sonal Pinto
Published

Purple Owl, a 60% keyboard powered by Seeed XIAO RP2040

Purple Owl is a 60% hotswap mechanical keyboard with underglow RGB powered by a tiny Seeed XIAO RP2040 and KMK Firmware.

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Purple Owl, a 60% keyboard powered by Seeed XIAO RP2040

Things used in this project

Hardware components

Seeed XIAO RP2040
Seeed Studio Seeed XIAO RP2040
×1

Hand tools and fabrication machines

Seeed Studio Fusion PCB/PCBA
Seeed Studio Fusion PCB/PCBA

Story

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Schematics

Purple Owl v1.0 PCB Schematic

Code

Scan Chain bringup

Python
"""
Basic key test
"""

import time
import digitalio
import board

# Pinout
# dat - D9 / MISO
# clk - D8 / SCK
# ld  - D7 / RX
# rgb - D6 / TX

DAT = digitalio.DigitalInOut(board.D9)
DAT.switch_to_input()

CLK = digitalio.DigitalInOut(board.D8)
CLK.switch_to_output(value=False, drive_mode=digitalio.DriveMode.PUSH_PULL)

LD  = digitalio.DigitalInOut(board.D7)
LD.switch_to_output(value=True, drive_mode=digitalio.DriveMode.PUSH_PULL)

NUM_KEYS = 61

# SRC: https://sourcegraph.com/github.com/adafruit/circuitpython/-/blob/shared-module/keypad/ShiftRegisterKeys.c
while True:
    time.sleep(0.1)

    # Lock the scan chain
    LD.value = True
    
    # Shift in scan chain
    i = 0
    while i < NUM_KEYS:
        key = DAT.value
        
        CLK.value = True
        CLK.value = False
        
        if not key:
            print(i)
            
        i += 1
    
    # Unlock the scan chain 
    LD.value = False

KMK main.py

Python
"""
Purple Owl v1.0 KMK Build
"""

import board

from kmk.kmk_keyboard import KMKKeyboard
from kmk.scanners.keypad import ShiftRegisterKeys
from kmk.keys import KC
from kmk.modules.layers import Layers
from kmk.extensions.RGB import RGB, AnimationModes


# Pinout
PIN_DAT = board.D9
PIN_CLK = board.D8
PIN_LD  = board.D7
PIN_RGB = board.D6
NUM_KEYS = 61

class PurpleOwl(KMKKeyboard):
    def __init__(self):
        # =============================================================
        # Scanner: 74HC165 scan chain
        self.matrix = ShiftRegisterKeys(
            clock=PIN_CLK,
            data=PIN_DAT,
            latch=PIN_LD,
            key_count=NUM_KEYS,
            value_to_latch=True,
            value_when_pressed=False,
            interval=0.02,
            max_events=64
        )

        # =============================================================
        # Physical Layout
        self.coord_mapping = [
            0,  4,  8, 12, 16, 20, 24, 28, 32, 36, 40, 44, 48, 52,
            1,  5,  9, 13, 17, 21, 25, 29, 33, 37, 41, 45, 49, 53,
            2,  6, 10, 14, 18, 22, 26, 30, 34, 38, 42, 46, 50, 54,
            3,  7, 11, 15, 19, 23, 27, 31, 35, 39, 43, 47, 51, 55,
                       56, 57, 58, 59, 60,
        ]

        # =============================================================
        # Extensions
        layer_ext = Layers()
        rgb_ext = RGB(
            pixel_pin=PIN_RGB, 
            num_pixels=16,
            hue_step=13,
            sat_step=26,
            val_step=26,
            animation_speed=5,
            animation_mode=AnimationModes.SWIRL,
        )
        rgb_ext._rgb_tog()

        self.modules = [layer_ext, rgb_ext]

        # =============================================================
        # Keymap
        _______ = KC.TRNS
        XXXXXXX = KC.NO

        # RGB
        UG_TOG = KC.RGB_TOG                     # Toggles RGB
        UG_HUI = KC.RGB_HUI                     # Increase Hue
        UG_HUD = KC.RGB_HUD                     # Decrease Hue
        UG_SAI = KC.RGB_SAI                     # Increase Saturation
        UG_SAD = KC.RGB_SAD                     # Decrease Saturation
        UG_VAI = KC.RGB_VAI                     # Increase Value
        UG_VAD = KC.RGB_VAD                     # Decrease Value
        UG_ANI = KC.RGB_ANI                     # Increase animation speed
        UG_AND = KC.RGB_AND                     # Decrease animation speed
        UG_M0  = KC.RGB_MODE_PLAIN              # Static RGB
        UG_M1  = KC.RGB_MODE_BREATHE            # Breathing animation
        UG_M2  = KC.RGB_MODE_RAINBOW            # Rainbow animation
        UG_M3  = KC.RGB_MODE_BREATHE_RAINBOW    # Breathing rainbow animation
        UG_M4  = KC.RGB_MODE_KNIGHT             # Knight Rider animation
        UG_M5  = KC.RGB_MODE_SWIRL              # Swirl animation

        # Layers
        LOWER = KC.MO(1)
        RAISE = KC.MO(2)

        self.keymap = [
            [   # Base
                KC.ESC,   KC.N1,    KC.N2,    KC.N3,    KC.N4,    KC.N5,    KC.N6,    KC.N7,    KC.N8,    KC.N9,    KC.N0,    KC.MINUS,  KC.EQUAL,  KC.BSPC,  
                KC.TAB,   KC.Q,     KC.W,     KC.E,     KC.R,     KC.T,     KC.Y,     KC.U,     KC.I,     KC.O,     KC.P,     KC.LBRC,   KC.RBRC,   KC.BSLS,
                KC.LCTL,  KC.A,     KC.S,     KC.D,     KC.F,     KC.G,     KC.H,     KC.J,     KC.K,     KC.L,     KC.SCLN,  KC.QUOT,   KC.UP,     KC.ENT,
                KC.LSFT,  KC.Z,     KC.X,     KC.C,     KC.V,     KC.B,     KC.N,     KC.M,     KC.COMM,  KC.DOT,   KC.SLSH,  KC.LEFT,   KC.DOWN,   KC.RGHT,
                                              KC.LGUI,  LOWER,   KC.SPC,    RAISE,    KC.LALT,
            ],
            [   # Lower
                KC.GRV,   _______,  _______,  _______,  _______,  _______,  _______,  _______,  _______,  _______,  _______,  _______,  _______,  _______,
                _______,   UG_TOG,  UG_M0,    UG_M1,    UG_M2,    UG_M3,    UG_M4,    UG_M5,    _______,  _______,  _______,  _______,  _______,  _______,
                _______,   UG_HUI,  UG_SAI,   UG_VAI,   UG_ANI,   _______,  _______,  _______,  _______,  _______,  _______,  _______,  _______,  _______,
                _______,   UG_HUD,  UG_SAD,   UG_VAD,   UG_AND,   _______,  _______,  _______,  _______,  _______,  _______,  _______,  _______,  _______,
                                              _______,  _______,  _______,  _______,  _______,
            ],
            [   # Raise
                KC.TILD,  _______,  _______,  _______,  _______,  _______,  _______,  _______,  _______,  _______,  _______,  _______,  _______,  _______,
                _______,  _______,  _______,  _______,  _______,  _______,  _______,  _______,  _______,  _______,  _______,  _______,  _______,  _______,
                _______,  _______,  _______,  _______,  _______,  _______,  _______,  _______,  _______,  _______,  _______,  _______,  _______,  _______,
                _______,  _______,  _______,  _______,  _______,  _______,  _______,  _______,  _______,  _______,  _______,  _______,  _______,  _______,
                                              _______,  _______,  _______,  _______,  _______,
            ],
        ]


if __name__ == '__main__':
    keyboard = PurpleOwl()
    keyboard.go()

KMK boot.py

Python
import supervisor
import board
import digitalio
import storage
import usb_cdc
import usb_hid
import usb_midi


# =============================================================
# KMK base boot.py
supervisor.set_next_stack_limit(4096 + 4096)

# =============================================================
# Purple Owl Dev Mode entry
#
# Latch the chain and poll the first bit of the scan data.
# If the key was pressed, then enter CircuitPython Dev Mode
# Else, turn off all USB enumerations except HID
#

DAT = digitalio.DigitalInOut(board.D9)
DAT.switch_to_input()

LD  = digitalio.DigitalInOut(board.D7)
LD.switch_to_output(value=True, drive_mode=digitalio.DriveMode.PUSH_PULL)

if DAT.value:
    storage.disable_usb_drive()
    usb_cdc.disable()
    usb_midi.disable()
    usb_hid.enable(boot_device=1)

DAT.deinit()
LD.deinit()

Purple Owl

Credits

Sonal Pinto

Sonal Pinto

1 project • 3 followers

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