HardLabs

Reference

doughnut923·Blossom·PCB files/blossom_pcb/reference.kicad_pcb

Reference PCB layout, top view — open source AVR/Arduino board by doughnut923

About the Reference PCB

Reference is an open source AVR/Arduino PCB design by doughnut923, published on GitHub under the MIT license. It is a 2-layer board measuring 339.1 × 118.7 mm, with 183 components from 34 distinct parts.

Its main chip is the ATMEGA32U4-AU, from the AVR/Arduino family. Other key parts include the USBLC6-2SC6. By type, the board carries 83 diodes, 67 switches, 15 connectors, 9 capacitors, 5 resistors and 2 ICs.

It belongs with the keyboards designs in this gallery.

From the project

Open-sourced Arisu-styled gasket-mounted keyboard

Key differences: - I removed the extra [B] key on the right half and shifted the [NM,.?] row to the left by 0.25U. - Shifted the 3 keys to the right and added arrow keys. - Tweaked the bottom so that the 1.5U keys doesn't protrude out a little.

Shifting the [NM,.?] row to the left by 0.25U required quite some work on the arrangement of keys for the right half. As a result, this does not give the same typing experience as Lyn's EM7 and TGR Alice. Lyn's EM7 and TGR Alice uses the home row as the center point to vertically align both halves while I used the number row instead. Due to the nature…

Reference, from the project README
From the project README

Main components on the Reference

USBLC6-2SC6ATMEGA32U4-AU

Reference bill of materials (BOM)

183 components, 34 distinct parts — part numbers from the project's BOM.

QtyPartRefs
1
USBLC6-2SC6
U1
1
ATMEGA32U4-AU
ATmega32U4-AU
U2
1
CRYSTAL_GND24
Crystal_GND24
Y1
1
USB_B_Micro
J1
1
MISO
J2
2
VCC
J3, J12
1
SCK
J4
1
MOSI
J5
1
RES
J6
2
GND
J7, J15
1
PF4
J8
1
PF5
J9
1
PF6
J10
1
PF7
J11
1
D+
J13
1
D-
J14
56
SW_Push
SW1, SW6, SW7, SW8, SW9, SW10, SW11, SW12 +48
5
SW_Push
SW2, SW5, SW14, SW46, SW60
2
SW_Push
SW3, SW54
1
SW_Push
SW4
Show 14 more
QtyPartRefs
1
SW_Push
SW23
1
SW_Push
SW37
1
SW_Push
SW57
1
SW_Push
SWR1
67
D
D1, D2, D3, D4, D5, D6, D7, D8 +59
16
WS2812B
D68, D69, D70, D71, D72, D73, D74, D75 +8
2
22PF
22pF
C1, C2
1
10UF
10uF
C3
1
1uF (±10%)
C4
1
1UF
1uF
C5
4
0.1UF
0.1uF
C6, C7, C8, C9
2
22
R1, R2
2
10K
R3, R4
1
500
R5

Reference design files

The KiCad project lives in the doughnut923/Blossom repository on GitHub; these links point at the commit this page was built from.

Reference: common questions

What microcontroller does the Reference use?

The Reference is built around the ATMEGA32U4-AU, from the AVR/Arduino family.

How big is the Reference PCB?

The Reference measures 339.1 × 118.7 mm, has 2 copper layers and is 1.6 mm thick.

How many components are on the Reference?

183 components, from 34 distinct parts, with part numbers taken from the project's own BOM. The full bill of materials is listed on this page.

Where can I download the Reference design files?

From the doughnut923/Blossom repository on GitHub, which has the KiCad layout and the BOM; the links under Design files point to each one.

Can I use the Reference design in my own project?

Yes, under the terms of its MIT license, which doughnut923 chose for the repository.

Can I test firmware for the Reference without the hardware?

Yes. HardLabs builds a simulation of the board from its netlist and BOM, so you can run and debug AVR/Arduino firmware against it before you order a PCB.

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