Alu
About the Alu PCB
Alu is an open source PCB design by jes, published on GitHub under the Unlicense license. It is a 2-layer board measuring 237.5 × 102.9 mm, with 79 components from 14 distinct parts.
Other key parts include the 74LS377, 74LS244, 74LS32, 74LS02 and 74LS08. By type, the board carries 26 resistors, 23 ICs, 23 capacitors and 7 connectors.
From the project
A homebrew 16-bit CPU with a homebrew Unix-like-ish operating system.
SCAMP is my homebrew 16-bit CPU. It stands for something like "Simple Computing and Arithmetic Microcoded Processor".
The CPU is very primitive. It doesn't support interrupts, and has no MMU, and no concept of privilege levels. It currently runs at 1 MHz, above that the CompactFlash interface falls over. It runs a homebrew operating system, with a homebrew programming language and compiler, and can self-host the kernel and all of the system utilities. The environment tastes a bit like an early Unix, but works like CP/M. I used the computer to complete almost all of Advent of Code 2021.
Main components on the Alu
Alu bill of materials (BOM)
79 components, 14 distinct parts.
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 3 | 74LS377 | DIP-20_W7.62mm_Socket | U1, U2, U4 |
| 1 | 74LS244 | DIP-20_W7.62mm_Socket | U3 |
| 2 | 74LS32 | DIP-14_W7.62mm_Socket | U5, U10 |
| 1 | 74LS02 | DIP-14_W7.62mm_Socket | U6 |
| 6 | 74LS08 | DIP-14_W7.62mm_Socket | U7, U8, U9, U16, U17, U20 |
| 2 | 74LS283 | DIP-16_W7.62mm_Socket | U11, U21 |
| 2 | 74LS157 | DIP-16_W7.62mm_Socket | U12, U22 |
| 6 | 74LS86 | DIP-14_W7.62mm_Socket | U13, U14, U15, U18, U19, U23 |
| 1 | Conn_02x30_Counter_Clockwise | PinSocket_2x30_P2.54mm_Horizontal | J1 |
| 3 | Conn_01x09_Male | PinHeader_1x09_P2.54mm_Vertical | J2, J3, J4 |
| 2 | Conn_01x03_Male | PinHeader_1x03_P2.54mm_Vertical | J5, J6 |
| 1 | Conn_01x02_Male | PinHeader_1x02_P2.54mm_Vertical | J7 |
| 23 | C | C_Disc_D5.0mm_W2.5mm_P2.50mm | C1, C2, C3, C4, C5, C6, C7, C8 +15 |
| 26 | R | R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R1, R2, R3, R4, R5, R6, R7, R8 +18 |
Alu design files
The KiCad project lives in the jes/scamp-cpu repository on GitHub; these links point at the commit this page was built from.
- Layoutkicad/alu/alu.kicad_pcb
Alu: common questions
How big is the Alu PCB?
The Alu measures 237.5 × 102.9 mm, has 2 copper layers and is 1.6 mm thick.
How many components are on the Alu?
79 components, from 14 distinct parts. The full bill of materials is listed on this page.
Where can I download the Alu design files?
From the jes/scamp-cpu repository on GitHub, which has the KiCad layout; the links under Design files point to each one.
Can I use the Alu design in my own project?
Yes, under the terms of its Unlicense license, which jes chose for the repository.
