Minus one
About the Minus one PCB
Minus one is an open source PCB design by google, published on GitHub under the Apache-2.0 license. It is a 2-layer board measuring 100 × 100 mm, with 43 components from 7 distinct parts.
It belongs with the retro computing designs in this gallery.
From the project
Phillip Pearson's retro hardware projects for the Acorn Electron
This is a simple Electron expansion that provides three cartridge slots, with the same pinout as the cartridge slots on the Plus 1 (except for the nROMSTB line, which is unimplemented) using a CPLD for address translation.
I made this after my Plus 1 broke, and it works very well in initial testing.
- Dave Hitchins (Retro Hardware) Mega Games Cartridge
- My 32kbflashcartridge (original and standard)
Minus one bill of materials (BOM)
43 components, 7 distinct parts — part numbers from the project's BOM.
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 3 | cartridge port | acorn_electron_cartridge_socket | CART0, CART2, CART4 |
| 2 | — | via_zigzag_1x44_2.54mm | staple1, staple2 |
| 33 | — | via_single | staple_single1, staple_single2, staple_single3, staple_single4, staple_single5, staple_single6, staple_single7, staple_single8 +25 |
| 2 | C28323 100n | C_0805_HandSoldering | C1, C2 |
| 1 | C49678 100n | C_0805_HandSoldering | C3 |
| 1 | C49678 1u | C_0805_HandSoldering | C4 |
| 1 | C28323 1u | C_0805_HandSoldering | C5 |
Minus one design files
The KiCad project lives in the google/myelin-acorn-electron-hardware repository on GitHub; these links point at the commit this page was built from.
Minus one: common questions
How big is the Minus one PCB?
The Minus one measures 100 × 100 mm, has 2 copper layers and is 1.6 mm thick.
How many components are on the Minus one?
43 components, from 7 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 Minus one design files?
From the google/myelin-acorn-electron-hardware repository on GitHub, which has the KiCad layout and the BOM; the links under Design files point to each one.
Can I use the Minus one design in my own project?
Yes, under the terms of its Apache-2.0 license, which google chose for the repository.
More boards in myelin-acorn-electron-hardware
Post box usb
92.9 × 45 mm102 parts4LApache-2.059
A3000 ram buffer
167 × 49.4 mm69 parts2LApache-2.059
Econet standalone
48.5 × 48 mm67 parts2LApache-2.059
Cpu socket expansion
42.6 × 74.7 mm52 parts2LApache-2.059
Raspberry PiFx2 tube cartridge adapter
66.5 × 85.5 mm51 parts2LApache-2.059
Xc9500xl 44 breakout
39.1 × 44.3 mm29 parts2LApache-2.059
Bga in two layers
25.4 × 35.6 mm23 parts2LApache-2.059
Acorn electron expansion
100 × 100 mm21 parts2LApache-2.059
Econet hub
70.7 × 36.6 mm20 parts2LApache-2.059
Master updateable megarom
36 × 49 mm18 parts2LApache-2.059
Archimedes bus scope
149.9 × 99.1 mm4 parts4LApache-2.059
Similar boards
OpenTendo
Redherring32
196.3 × 118.7 mm93 parts2LTAPR-OHL-1.0850
24pin flex interposer
Wren6991
29 × 32 mm3 parts2LNo license508
Sram dev board
50 × 50 mm12 parts2LNo license508
GB-BRK-SLOT-A
Gekkio
81 × 80 mm20 parts2LCC-BY-4.0376
GB-BRK-SLOT-B
81 × 80 mm20 parts2LCC-BY-4.0376
GB-BRK-CPU-G2
80 × 80 mm12 parts2LCC-BY-4.0376