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Ampersand

calvin-mcd·ampersand-ec·Project/ampersand.kicad_pcb

Ampersand PCB layout, top view — open source STM32 board by calvin-mcd

About the Ampersand PCB

Ampersand is an open source STM32 PCB design by calvin-mcd, published on GitHub under the GPL-3.0 license. It is a 2-layer board measuring 257.2 × 76.2 mm, with 40 components from 13 distinct parts.

Its main chip is the STM32F072CBT6, from the STM32 family. Other key parts include the XC6206PXXXMR-REGULATOR_LINEAR, 74HC4051 and OPA354. By type, the board carries 20 resistors, 14 capacitors, 5 ICs and 1 connector.

From the project

ampersand ec pcb

This an open-source 2-layer EC pcb for the Ampersand keyboard designed by whitefacemountain. Ampersand is a gummyworm mounted 13.5u keyboard with minimum 40s support needed.

The firmware has been adapted by whitefacemountain and pi and is based on cipulot's Menhir firmware.

As the Ampersand case is designed for a MX pcb using an oring, this EC pcb requires the use of EC naevies switches. Other EC switches might only work with heavy modifications of the outer housings.

Ampersand, from the project README
From the project README

Main components on the Ampersand

STM32F072CBT6XC6206PXXXMR-REGULATOR_LINEAR74HC4051OPA354

Ampersand bill of materials (BOM)

40 components, 13 distinct parts — part numbers from the project's BOM.

QtyPartRefs
1
STM32F072CBT6
U1
1
XC6206PXXXMR-REGULATOR_LINEAR
XC6206PxxxMR-Regulator_Linear
U2
2
74HC4051
U3, U5
1
OPA354
U4
1
C160404
JST SH
J1
9
100NF
100nF
C1, C2, C3, C4, C6, C8, C11, C12 +1
1
10UF
10uF
C5
3
1UF
1uF
C7, C9, C10
1
C1530
220pF NP0
C13
4
100
R1, R2, R3, R4
1
10K
10k
R5
14
100K
100k
R6, R7, R8, R9, R10, R11, R14, R15 +6
1
1k
R12

Ampersand design files

The KiCad project lives in the calvin-mcd/ampersand-ec repository on GitHub; these links point at the commit this page was built from.

Ampersand: common questions

What microcontroller does the Ampersand use?

The Ampersand is built around the STM32F072CBT6, from the STM32 family.

How big is the Ampersand PCB?

The Ampersand measures 257.2 × 76.2 mm, has 2 copper layers and is 1.6 mm thick.

How many components are on the Ampersand?

40 components, from 13 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 Ampersand design files?

From the calvin-mcd/ampersand-ec repository on GitHub, which has the KiCad layout, the schematic and the BOM; the links under Design files point to each one.

Can I use the Ampersand design in my own project?

Yes, under the terms of its GPL-3.0 license, which calvin-mcd chose for the repository.

Can I test firmware for the Ampersand without the hardware?

Yes. HardLabs builds a simulation of the board from its netlist and BOM, so you can run and debug STM32 firmware against it before you order a PCB.

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