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 layers306.1 × 130.2 mm
8-Bit CPU 32k
slu4coder/Minimal-64-Home-Computer94Legacy: Full TTL-only home computer with VGA and PS/2 and twice the processing power of a Commodore 64
- Size
- 306.1 × 130.2 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 132
- Nets
- 303
- Pads
- 1,278
- Tracks, vias
- 6,667, 50
- Pours
- 1
- Routed
- Yes
- KiCad
- KiCad 6 (file 20211014)
- Created
- 16 Dec 2022
- Updated
- 9 Jun 2026
Overview
8-Bit CPU 32k is an open-source printed circuit board by slu4coder, from the slu4coder/Minimal-64-Home-Computer repository on GitHub. It is a 2-layer board of 306.1 × 130.2 mm with 132 parts on 303 nets, routed with 6,667 tracks and 50 vias.
It is built around the 74HC245D, 74HC161S and 74HC00D, with the 74HC32D, 74HC574D and 74HC08D among its other parts. Its parts include 61 ICs, 32 resistors, 27 capacitors, 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
74HC00D
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 Gates74HC32D
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 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 Flops74HC08D
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 Gates
74HC165D
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 Logic74HC590D
SO-16-40℃~+125℃ 1 15ns 2V~6V 61MHz 8 Asynchronous Divide-by-2 Rising Edge Up Counter SO-16 Counters, Dividers ROHSNexperiaCounters, Dividers74HC595
SOP-16-40℃~+85℃ 1 100ns@5V,50pF 10MHz 2V~6V 74HC 8 Serial-to-Serial or Parallel Tri-State SOP-16 Shift Registers ROHSGRShift Registers74HC86D
SO-14-40℃~+125℃ 1.5V~4.2V 20ns@6V,50pF 2V~6V 2uA 4 5.2mA 5.2mA 500mV~1.8V 74HC Series XOR Gate SOIC-14 Logic Gates ROHSNexperiaLogic Gates
README
README.mdLegacy: Minimal 64 Home Computer
See https://github.com/slu4coder/Minimal-64x4-Home-Computer for the most recent version.
This is a free and non-commercial project. I am in no way associated with any activies selling this as a product. Any such activity represents a license violation. Individual licenses apply for hardware and software parts. Please refer to appropriate documentations for detailed licensing information.
Here is my take on 80's home computer magic: The most computer from the least logic or the shortest way from TTL to Space Invaders.
Introductory videos: https://www.youtube.com/watch?v=3zGTsi4AYLw, https://www.youtube.com/watch?v=FJsnKu20ch8
Reference manual: https://docs.google.com/document/d/1e4hL9Z7BLIoUlErWgJOngnSMYLXjfnsZB9BtlwhTC6U/edit?usp=sharing
Visit my YouTube channel: https://www.youtube.com/channel/UCXYQcMpUBT3aaQKfmAVJNow
FEATURES
● Only 56 74HCxx logic ICs, 1x 6C1008 SRAM, 4x 39SF0x0 FLASH, BUT 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 slot and serial UART port
● 8MHz system clock, 6MHz CPU clock with 0.84Mips (2x Commodore 64)
● 128 instructions including conditional branching, subroutines, stack and word operations
● 2 data registers A, B plus two more "software" registers X, Y
● 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'
● Emulator, cross-assembler (Windows) and classic games (TETRIS clone, Space Invaders clone)
● Open-source emulators in JAVA/PROCESSING and JAVASCRIPT/p5.js https://editor.p5js.org/slu4coder/full/aOUivViNt
See "CHANGE LOG" for a brief summary of the relevant updates.
Have fun!
Parts
132| Qty | Value | Footprint | References |
|---|---|---|---|
| 26 | 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 +10 |
| 16 | 470 | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R5, R6, R7, R8, R9, R10, R11, R12, R13, R14, R15, R16, R17, R18, R19, R20 |
| 14 | 74HC161 | Package_DIP:DIP-16_W7.62mm | U3, U7, U8, U9, U10, U11, U14, U15, U17, U18, U33, U36, U37, U50 |
| 10 | 74HC245 | Package_DIP:DIP-20_W7.62mm | U12, U16, U19, U21, U23, U26, U46, U48, U60, U61 |
| 8 | 330 | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R25, R26, R27, R28, R29, R30, R31, R32 |
| 5 | 4.7k | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R2, R21, R22, R23, R24 |
| 4 | 74HC00 | Package_DIP:DIP-14_W7.62mm | U1, U40, U43, U55 |
| 4 | 74HC32 | Package_DIP:DIP-14_W7.62mm | U42, U49, U58, U59 |
| 4 | 74HC574 | Package_DIP:DIP-20_W7.62mm | U2, U20, U32, U53 |
| 4 | M2 | MountingHole:MountingHole_2.2mm_M2 | H1, H2, H3, H4 |
| 3 | 74HC08 | Package_DIP:DIP-14_W7.62mm | U22, U47, U56 |
| 2 | 74HC165 | Package_DIP:DIP-16_W7.62mm | U38, U39 |
| 2 | 74HC193 | Package_DIP:DIP-16_W7.62mm | U34, U52 |
| 2 | 74HC283 | Package_DIP:DIP-16_W7.62mm | U24, U25 |
| 2 | 74HC4078 | Package_DIP:DIP-14_W7.62mm | U29, U30 |
| 2 | 74HC590 | Package_DIP:DIP-16_W7.62mm | U41, U45 |
| 2 | 74HC595 | Package_DIP:DIP-16_W7.62mm | U35, U51 |
| 2 | 74HC86 | Package_DIP:DIP-14_W7.62mm | U27, U28 |
| 2 | 75 | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R1, R3 |
| 1 | 150 | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R4 |
| 1 | 16MHz | Oscillator:Oscillator_DIP-14 | X1 |
| 1 | 200pF | Capacitor_THT:C_Disc_D3.4mm_W2.1mm_P2.50mm | C6 |
| 1 | 5V* | Connector_PinSocket_2.54mm:PinSocket_2x03_P2.54mm_Vertical | J5 |
| 1 | 74HC04 | Package_DIP:DIP-14_W7.62mm | U31 |
| 1 | 74HC166 | Package_DIP:DIP-16_W7.62mm | U44 |
| 1 | 74HCT132 | Package_DIP:DIP-14_W7.62mm | U57 |
| 1 | AS6C1008 SRAM | Package_DIP:DIP-32_W15.24mm | U13 |
| 1 | EXPANSION PORT | Connector_PinSocket_2.54mm:PinSocket_2x16_P2.54mm_Vertical | J3 |
| 1 | LOGO | logo:logo | G*** |
| 1 | PS/2 Keyboard | ArduinoPC:FP_MINI_DIN_6_PS2 | J4 |
| 1 | RESET | Button_Switch_THT:SW_PUSH_6mm | SW1 |
| 1 | SST39SF010A HSB | Package_DIP:DIP-32_W15.24mm_Socket | U4 |
| 1 | SST39SF010A LSB | Package_DIP:DIP-32_W15.24mm_Socket | U6 |
| 1 | SST39SF010A MSB | Package_DIP:DIP-32_W15.24mm_Socket | U5 |
| 1 | SST39SF040A 512KB | Package_DIP:DIP-32_W15.24mm_Socket | U54 |
| 1 | UART | Connector_PinSocket_2.54mm:PinSocket_1x06_P2.54mm_Vertical | J1 |
| 1 | VGA connector | ArduinoPC:VGA DSUB15HD_female | J2 |
Questions
How big is the 8-Bit CPU 32k PCB?
It measures 306.1 × 130.2 mm and has 2 copper layers, 1.6 mm thick.
What parts does the 8-Bit CPU 32k use?
132 parts, built around the 74HC245D, 74HC161S, 74HC00D and 74HC32D. 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-64-Home-Computer repository on GitHub, at the commit this page was made from: the board is Revision 1.2/KiCAD/8-Bit CPU 32k.kicad_pcb and its schematic Revision 1.2/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.
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