2 layers245.1 × 160 mm
8-Bit CPU 32k
slu4coder/Minimal-64x4-Home-Computer
My DIY TTL home computer with VGA and PS/2 and 4x the processing power of a Commodore C64 or Apple II.
139 parts326
2 layers110 × 110 mm
Custom cpu
axelo/custom-cpuCutom CPU built from 7400-series integrated circuits (and FLASH roms)
- Size
- 110 × 110 mm
- Copper layers
- 2
- Thickness
- 1.67 mm
- Parts
- 47
- Nets
- 113
- Pads
- 498
- Tracks, vias
- 2,485, 99
- Pours
- 1
- Routed
- Yes
- KiCad
- KiCad 7 (file 20221018)
- Created
- 3 Mar 2024
- Updated
- 30 Jan 2025
Overview
Custom cpu is an open-source printed circuit board by axelo, from the axelo/custom-cpu repository on GitHub, published under the MIT licence. It is a 2-layer board of 110 × 110 mm with 47 parts on 113 nets, routed with 2,485 tracks and 99 vias.
It is built around the 74HC245D, 74HC161S and 74HC32D, with the 74HC00D, 74HC157D and 74HC377D among its other parts. Its parts include 24 ICs, 11 capacitors, 5 connectors, 1 resistor and 1 switch.
Main components
8
74HC245D
SO-20-300mil-40℃~+125℃ 1 160uA 2V~6V 7.8mA 7.8mA 74HC 8 9ns@4.5V,50pF Bidirectional Tri-State SOIC-20-300mil Buffers, Drivers, Receivers, Transceivers ROHSNexperiaBuffers, Drivers, Receivers, Transceivers
74HC161S
SOP-160℃~+70℃ 20MHz 2V~6V 4 500mW Asynchronous Hexadecimal Counter Rising Edge Synchronous Up Counter SOP-16 Counters, Dividers ROHSGRCounters, Dividers
74HC32D
SOP-14-40℃~+125℃ 1.5V~4.2V 1.9V、4.4V、5.9V 100mV、400mV、400mV 2 2V~6V 2uA 4 5.2mA 5.2mA 500mV~1.8V 6ns@6V,50pF 74HC Series OR Gate SOIC-14 Logic Gates ROHSNexperiaLogic Gates74HC00D
SOP-14-40℃~+125℃ 1.5V、3.15V、4.2V 1.9V、3.7V、5.9V 100mV、400mV、400mV 2 2V~6V 4 40uA 5.2mA 5.2mA 500mV~1.8V 74HC Series 7ns@6V,50pF NAND Gate SOIC-14 Logic Gates ROHSNexperiaLogic Gates
74HC157D
SO-16-40℃~+125℃ 10ns@6.0V,50pF 160uA 2V~6V 5.2mA 5.2mA 74HC 8/4 Multiplexer Single Supply SOIC-16 Signal Switches, Multiplexers, Decoders ROHSNexperiaSignal Switches / Encoders & Decoders / Multiplexers74HC377D
SO-20-300mil-40℃~+125℃ 1 12ns 16ns@4.5V,50pF 2V~6V 3.5pF 3ns 4mA 4mA 74HC Series 77MHz 8 8uA D-Type Enable Rising Edge SOIC-20-300mil Flip Flops ROHSNexperiaFlip Flops74HC574D
SOP-20L-40℃~+125℃ 1 13ns 15ns@6V,50pF 2.7V~6V 20uA 28MHz 5ns 6.5pF 7.8mA 7.8mA 74HC Series 8 D-Type Enable Rising Edge Tri-State SOP-20L Flip Flops ROHSMDDFlip Flops
MCP100-450DI/TO
TO-92-3-40℃~+85℃@(TA) 1 150ms 1V~5.5V 4.375V 45uA Active Low Push-pull Simple Reset/Power-On Reset TO-92-3 Supervisor and Reset ICs ROHSMicrochip TechnologySupervisor And Reset ICs
README
README.mdcustom-cpu
A custom CPU built from 7400-series integrated circuits.
Parts
47| Qty | Value | Footprint | References |
|---|---|---|---|
| 11 | 0.1 nF | Capacitor_THT:C_Disc_D5.0mm_W2.5mm_P5.00mm | C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11 |
| 7 | 74HC161 | Package_DIP:DIP-16_W7.62mm_Socket | U4, U6, U8, U9, U14, U16, U17 |
| 5 | 74HC32 | Package_DIP:DIP-14_W7.62mm_Socket | U3, U5, U7, U12, U24 |
| 4 | MountingHole | MountingHole:MountingHole_3.2mm_M3 | H1, H2, H3, H4 |
| 3 | 74HC00 | Package_DIP:DIP-14_W7.62mm_Socket | U21, U22, U23 |
| 2 | Conn_01x08 | Connector_PinSocket_2.54mm:PinSocket_1x08_P2.54mm_Vertical | J2, J5 |
| 2 | SST39SF010 | Package_DIP:DIP-32_W15.24mm_Socket | U1, U2 |
| 1 | 10 MHz | Oscillator:Oscillator_DIP-14 | X1 |
| 1 | 10K | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R1 |
| 1 | 628128 | Package_DIP:DIP-32_W15.24mm_Socket | U11 |
| 1 | 74HC157 | Package_DIP:DIP-16_W7.62mm_Socket | U10 |
| 1 | 74HC245 | Package_DIP:DIP-20_W7.62mm_Socket | U20 |
| 1 | 74HC377 | Package_DIP:DIP-20_W7.62mm_Socket | U15 |
| 1 | 74HC574 | Package_DIP:DIP-20_W7.62mm_Socket | U18 |
| 1 | Conn_01x02 | Connector_PinSocket_2.54mm:PinSocket_1x02_P2.54mm_Vertical | J3 |
| 1 | Conn_01x05 | Connector_PinSocket_2.54mm:PinSocket_1x05_P2.54mm_Vertical | J4 |
| 1 | Conn_02x04_Odd_Even | Connector_PinSocket_2.54mm:PinSocket_2x04_P2.54mm_Vertical | J1 |
| 1 | MCP100-450D | Connector_PinHeader_2.00mm:PinHeader_1x03_P2.00mm_Vertical | U19 |
| 1 | RESET | Button_Switch_THT:SW_PUSH_6mm | SW1 |
| 1 | SST39SF040 | Package_DIP:DIP-32_W15.24mm_Socket | U13 |
Questions
How big is the Custom cpu PCB?
It measures 110 × 110 mm and has 2 copper layers, 1.67 mm thick.
What parts does the Custom cpu use?
47 parts, built around the 74HC245D, 74HC161S, 74HC32D and 74HC00D. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
Where can I download the Custom cpu KiCad files?
From the axelo/custom-cpu repository on GitHub, at the commit this page was made from: the board is kicad/custom-cpu.kicad_pcb and its schematic kicad/custom-cpu.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Custom cpu design in my own project?
Its repository publishes it under the MIT licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).
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