2 layers231.8 × 158.1 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.
123 parts326
2 layers245.1 × 160 mm
8-Bit CPU 32k
slu4coder/Minimal-64x4-Home-Computer326My DIY TTL home computer with VGA and PS/2 and 4x the processing power of a Commodore C64 or Apple II.
- Size
- 245.1 × 160 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 139
- Nets
- 317
- Pads
- 1,396
- Tracks, vias
- 5,224, 42
- Pours
- 1
- Routed
- Yes
- KiCad
- KiCad 8.0 (file 20240108)
- Created
- 29 Mar 2024
- Updated
- 30 Jul 2026
Overview
8-Bit CPU 32k is an open-source printed circuit board by slu4coder, from the slu4coder/Minimal-64x4-Home-Computer repository on GitHub. It is a 2-layer board of 245.1 × 160 mm with 139 parts on 317 nets, routed with 5,224 tracks and 42 vias.
It is built around the 74HC245D, 74HC161S and 74HC32D, with the 74HC157D, 74HC377D and 74HC00D among its other parts. Its parts include 67 ICs, 33 capacitors, 27 resistors, 5 connectors and 1 switch. It belongs with the retro computing and games boards of this library.
Main components
12
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 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 Flops74HC00D
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 Gates74HC574D
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 Flops74HC02
-- Logic Gates ROHSonsemiLogic Gates74HC08D
SOP-14-40℃~+125℃ 1.5V~4.2V 1.9V、3.7V、5.2V 100mV、400mV 2 27ns@4.5V,50pF 2V~6V 2uA 4 5.2mA 5.2mA 500mV~1.8V 74HC Series AND Gate SOIC-14 Logic Gates ROHSNexperiaLogic Gates74HC165D
SO-16-40℃~+125℃ 1 28ns@6V,50pF 2V~6V 35MHz 500mW 74HC 8 Parallel or Serial to Serial SOIC-16 Shift Registers ROHSNexperiaShift Registers74HC193D
SO-16-40℃~+125℃ 1 18ns@6V 2V~6V 4 49MHz 500mW 74HC Asynchronous Divide-by-2 Reset function、Synchronous counting、Asynchronous parallel load、Multi-mode counting Rising Edge Synchronous Up Counter、Down Counter SO-16 Counters, Dividers ROHSNexperiaCounters / Dividers
74HC283P-E
-- Specialty Logic ROHSRenesas ElectronicsSpecialty Logic
README
README.mdMinimal 64x4 Redux Home Computer
Here is my latest take on 1980's home computer magic: The most computer from the least logic or the shortest way from TTL to Space Invaders.
This is a free and non-commercial project. I am in no way associated with any activies selling the Minimal 64x4 as a product. Any such activity represents a license violation. Individual licenses apply for hardware and software parts. Please refer to the applicable documentations for detailed licensing information.
Introductory video: https://www.youtube.com/watch?v=L1oECH6rPvs
Online emulator (sorry, no Redux): https://editor.p5js.org/slu4coder/sketches/lRq1gyYR2
Reference manual: https://docs.google.com/document/d/1-nDv_8WEG1FrlO3kEK0icoYo-Z-jlhpCMiCstxGOCjQ/edit?usp=sharing
Visit my YouTube channel: https://www.youtube.com/channel/UCXYQcMpUBT3aaQKfmAVJNow
Take a look at these repositories of fellow Minimal 64x4 enthusiasts for more games and fascinating projects:
https://github.com/hans61/Minimal-64x4-Games
https://github.com/hans61/Minimal-64x4-Expansion
https://github.com/michaelkamprath/minimal-64x4-expansion-cards
https://github.com/michaelkamprath/extended-min
FEATURES
● Only 57 74HCxx logic ICs, 2x 6C1008 SRAM, 4x 39SF0x0 FLASH, NO MICROCONTROLLER!
● Textbook 'Von-Neumann' architecture, 8-bit data bus, 16-bit address bus, 24 control signals
● 64KB RAM, 512KB FLASH SSD with file system (format, load, save, dir, delete)
● Monochrome VGA output 400 x 240 pixels, PS/2, expansion port and serial UART interface
● 8MHz CPU clockrate, 1.8Mips - that's more than 4x the commonly quoted Mips value of a 6502 running at 1MHz like in a Commodore C64 or Apple II
● 256 instructions including conditional branching, subroutines, stack, word, long and zero-page operations
● 2 data registers A & B, ALU supporting ADD, SUBTRACT, AND, OR with 3 flags (negative, carry and zero)
● Full native tool-chain: MinOS, text editor, assembler, fast Python-like interpreter 'MIN'
● Cycle-exact emulator, cross-assembler (both for Windows and Linux) and classic games (TETRIS clone, Space Invaders clone, 3D Maze)
If you like this project and want to give something back, you can do so via PayPal. Thanks!
https://paypal.me/CarstenHerting
Have fun!
See "CHANGE LOG" for a brief summary of the recent updates.
Parts
139| Qty | Value | Footprint | References |
|---|---|---|---|
| 29 | 100nF | Capacitor_THT:C_Disc_D3.4mm_W2.1mm_P2.50mm | C1, C2, C10, C11, C12, C13, C14, C15, C16, C17, C18, C19, C20, C21, C22, C23 +13 |
| 16 | 470 | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R2, R9, R10, R11, R12, R13, R14, R15, R16, R17, R18, R19, R20, R21, R22, R23 |
| 14 | 74HC161 | Package_DIP:DIP-16_W7.62mm_Socket | U11, U15, U19, U24, U26, U27, U28, U29, U30, U32, U48, U49, U52, U53 |
| 8 | 74HC245 | Package_DIP:DIP-20_W7.62mm_Socket | U42, U44, U46, U50, U56, U64, U65, U66 |
| 6 | 74HC32 | Package_DIP:DIP-14_W7.62mm_Socket | U2, U7, U33, U58, U60, U62 |
| 4 | 22pF | Capacitor_THT:C_Disc_D3.4mm_W2.1mm_P2.50mm | C30, C31, C32, C33 |
| 4 | 4.7k | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R1, R3, R4, R5 |
| 4 | 74HC157 | Package_DIP:DIP-16_W7.62mm_Socket | U22, U43, U47, U51 |
| 4 | 74HC377 | Package_DIP:DIP-20_W7.62mm_Socket | U5, U10, U20, U45 |
| 4 | M2 | MountingHole:MountingHole_2.2mm_M2 | H1, H2, H3, H4 |
| 3 | 74HC00 | Package_DIP:DIP-14_W7.62mm_Socket | U3, U4, U8 |
| 3 | 74HC574 | Package_DIP:DIP-20_W7.62mm_Socket | U38, U40, U41 |
| 2 | 150 | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R6, R26 |
| 2 | 68 | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R7, R8 |
| 2 | 74HC02 | Package_DIP:DIP-14_W7.62mm_Socket | U1, U6 |
| 2 | 74HC08 | Package_DIP:DIP-14_W7.62mm_Socket | U61, U63 |
| 2 | 74HC165 | Package_DIP:DIP-16_W7.62mm_Socket | U12, U13 |
| 2 | 74HC193 | Package_DIP:DIP-16_W7.62mm_Socket | U14, U18 |
| 2 | 74HC283 | Package_DIP:DIP-16_W7.62mm_Socket | U55, U59 |
| 2 | 74HC590 | Package_DIP:DIP-16_W7.62mm_Socket | U37, U39 |
| 2 | 74HC595 | Package_DIP:DIP-16_W7.62mm_Socket | U16, U17 |
| 2 | 74HC86 | Package_DIP:DIP-14_W7.62mm_Socket | U54, U57 |
| 1 | 0 | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R27 |
| 1 | 100 | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R25 |
| 1 | 16MHz | Oscillator:Oscillator_DIP-14 | X1 |
| 1 | 200 | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R24 |
| 1 | 74HC166 | Package_DIP:DIP-16_W7.62mm_Socket | U35 |
| 1 | 74HC4002 | Package_DIP:DIP-14_W7.62mm_Socket | U67 |
| 1 | 74HCT132 | Package_DIP:DIP-14_W7.62mm_Socket | U9 |
| 1 | AS6C1008 SRAM | Package_DIP:DIP-32_W15.24mm_Socket | U34 |
| 1 | AS6C62256 or AS6C1008 VRAM | Package_DIP:DIP-32_W15.24mm_Socket | U36 |
| 1 | EXPANSION PORT | Connector_PinSocket_2.54mm:PinSocket_2x16_P2.54mm_Vertical | J3 |
| 1 | LOGO | logo:logo | G*** |
| 1 | POWER | Connector_PinSocket_2.54mm:PinSocket_2x03_P2.54mm_Vertical | J5 |
| 1 | PS/2 | ArduinoPC:FP_MINI_DIN_6_PS2 | J2 |
| 1 | RESET | Button_Switch_THT:SW_PUSH_6mm | SW1 |
| 1 | SST39SF010..040 HSB | Package_DIP:DIP-32_W15.24mm_Socket | U21 |
| 1 | SST39SF010..040 LSB | Package_DIP:DIP-32_W15.24mm_Socket | U25 |
| 1 | SST39SF010..040 MSB | Package_DIP:DIP-32_W15.24mm_Socket | U23 |
| 1 | SST39SF040 512KB SSD | Package_DIP:DIP-32_W15.24mm_Socket | U31 |
| 1 | UART | Connector_PinSocket_2.54mm:PinSocket_1x06_P2.54mm_Vertical | J1 |
| 1 | VGA | ArduinoPC:VGA DSUB15HD_female | J4 |
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Questions
How big is the 8-Bit CPU 32k PCB?
It measures 245.1 × 160 mm and has 2 copper layers, 1.6 mm thick.
What parts does the 8-Bit CPU 32k use?
139 parts, built around the 74HC245D, 74HC161S, 74HC32D and 74HC157D. 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 8-Bit CPU 32k KiCad files?
From the slu4coder/Minimal-64x4-Home-Computer repository on GitHub, at the commit this page was made from: the board is Revision 1.1/KiCAD8/8-Bit CPU 32k.kicad_pcb and its schematic Revision 1.1/KiCAD/8-Bit CPU 32k.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the 8-Bit CPU 32k design in my own project?
Its repository states no licence, so its author keeps all rights: ask slu4coder before reusing the design.