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4 layers246.4 × 185.4 mm8bit computer, the printed circuit board in 3D

8bit computer

tonygilkerson/8bit-computer

8-bit Computer by Ben Eater

Open in PCBKitView on GitHub.kicad_pcb
Size
246.4 × 185.4 mm
Copper layers
4
Thickness
1.6 mm
Parts
281
Nets
383
Pads
1,309
Tracks, vias
3,194, 2
Pours
4
Routed
Yes
KiCad
KiCad 9.0 (file 20241229)
Created
7 Mar 2026
Updated
22 Mar 2026

Overview

8bit computer is an open-source printed circuit board by tonygilkerson, from the tonygilkerson/8bit-computer repository on GitHub. It is a 4-layer board of 246.4 × 185.4 mm with 281 parts on 383 nets, routed with 3,194 tracks and 2 vias.

It is built around the 74LS245SC, 74LS173SC and 74LS04PC, with the 74LS157PC, 74LS00SC and 74LS161DC among its other parts. Its parts include 104 resistors, 85 diodes, 53 ICs, 24 capacitors and 8 switches. It belongs with the retro computing and games boards of this library.

Main components

11

README

README.md

8bit-computer

This is my project to document the building of an 8-bit computer based on the design by Ben Eater.

Build an 8-bit computer from scratch, by Ben Eater

Getting started

Appendix ? - Notes

This is a start of my notes. Just brain dump here until I organize things.

Other implementations to use for modification ideas:

  • Config 101 - Modular PCB version YouTube - I like this guys modular PCB design.
  • Here is his Brovo Project all PCV based - YouTube

Shop

TODO clean this up, make it look like this: notebook/docs/tech/product.md/#PCBs and More from Schmalztech.com

  • digikey

direct with https://www.schmalztech.com/ and Free shipping on all U.S. orders over $30

Appendix ? - Parts List

See the original parts list

DEVTODO - source each item

QtyDescriptionSourceNotes
122 AWG Solid Tinned-Copper Hook-Up Wire
101kΩ resistor
910kΩ resistor
1100kΩ resistor
24470Ω resistor
11MΩ resistor
11MΩ potentiometer
60.01µF capacitor
160.1µF capacitor
11µF capacitor
4555 timer IC
274LS00 (Quad NAND gate)
174LS02 (Quad NOR gate)
574LS04 (Hex inverter)
374LS08 (Quad AND gate)
174LS32 (Quad OR gate)
174LS107 (Dual JK flip-flop) Note: The videos use the 74LS76 which is extremely difficult to find. The 74LS107 is functionally equivalent but be careful: it has a different pinout.
274LS86 (Quad XOR gate)
174LS138 (3-to-8 line decoder)
174LS139 (Dual 2-line to 4-line decoder)
474LS157 (Quad 2-to-1 line data selector)
274LS161 (4-bit synchronous binary counter)
874LS173 (4-bit D-type register)
274189 (64-bit random access memory)
674LS245 (Octal bus transceiver)
174LS273 (Octal D flip-flop)
274LS283 (4-bit binary full adder)
328C16 EEPROM
3Double-throw toggle switch
3Momentary 6mm tact switch
18-position DIP switch
14-position DIP switch
44Red LED
8Yellow LED
12Green LED
21Blue LED
4Common cathode 7-segment display

Appendix ? - Kits

On the kits page you can buy an all in one or individual kits. I think I will start with the clock and see how it goes.

  • Kit 1: Clock module
  • Kit 2: Registers and ALU
  • Kit 3: RAM and program counter
  • Kit 4: Output and control logic

Parts

281
QtyValueFootprintReferences
83220Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_HorizontalR16, R17, R18, R19, R20, R21, R22, R23, R24, R25, R26, R27, R100, R101, R102, R103 +67
44REDLED_THT:LED_D5.0mmD2, D10, D11, D12, D13, D14, D15, D16, D17, D18, D19, D20, D21, D22, D23, D24 +28
21BLUELED_THT:LED_D5.0mmD1, D26, D27, D28, D29, D58, D59, D60, D61, D62, D63, D64, D65, D66, D67, D68 +5
160.1µFCapacitor_THT:C_Disc_D4.3mm_W1.9mm_P5.00mmC1, C3, C10, C11, C12, C13, C14, C15, C16, C17, C18, C19, C20, C21, C22, C23
12GREENLED_THT:LED_D5.0mmD34, D35, D49, D50, D52, D53, D55, D56, D82, D83, D84, D85
101KResistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_HorizontalR1, R2, R3, R5, R6, R58, R63, R64, R65, R75
810KResistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_HorizontalR8, R9, R10, R11, R12, R13, R14, R15
874LS173Package_DIP:DIP-16_W7.62mmU8, U9, U11, U12, U14, U15, U19, U34
8YELLOWLED_THT:LED_D5.0mmD30, D31, D32, D33, D44, D45, D46, D47
60.01µFCapacitor_THT:C_Disc_D4.3mm_W1.9mm_P5.00mmC2, C4, C5, C7, C8, C9
674LS245Package_DIP:DIP-20_W7.62mmU7, U10, U13, U17, U30, U36
574LS04Package_DIP:DIP-14_W7.62mmU4, U28, U29, U49, U53
474LS157Package_DIP:DIP-16_W7.62mmU26, U27, U32, U33
47SEGMENT_CCDisplay_7Segment:7SegmentLED_LTS6760_LTS6780U40, U41, U42, U43
4LM555Package_DIP:DIP-8_W7.62mmU1, U2, U3, U39
4MountingHole_3.2mm_M3MountingHole:MountingHole_3.2mm_M3, , ,
328C16Package_DIP:DIP-24_W15.24mm_SocketU45, U47, U52
374LS08Package_DIP:DIP-14_W7.62mmU5, U23, U46
3SW_SPDT8bit-custom-footprints:DPDT-pushbuttonSW2, SW6, SW7
274189Package_DIP:DIP-16_W7.62mmU24, U25
274LS00Package_DIP:DIP-14_W7.62mmU31, U51
274LS161Package_DIP:DIP-16_W7.62mmU35, U48
274LS283Package_DIP:DIP-16_W7.62mmU20, U21
274LS86Package_DIP:DIP-14_W7.62mmU16, U18
2SW_PushButton_Switch_THT:SW_PUSH_6mm_H5mmSW1, SW4
1100KResistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_HorizontalR66
110kResistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_HorizontalR104
110µFCapacitor_THT:CP_Radial_D5.0mm_P2.00mmC24
11M8bit-custom-footprints:Potentiometer-5.5mmRV1
11MResistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_HorizontalR4
11µFCapacitor_THT:CP_Radial_D5.0mm_P2.00mmC6
174LS02Package_DIP:DIP-14_W7.62mmU22
174LS138Package_DIP:DIP-16_W7.62mmU50
174LS139Package_DIP:DIP-16_W7.62mmU38
174LS273Package_DIP:DIP-20_W7.62mmU44
174LS32Package_DIP:DIP-14_W7.62mmU6
174LS76Package_DIP:DIP-16_W7.62mmU37
1G***pcb-battery:BenEatersvg2mod
1ResetButton_Switch_THT:SW_PUSH_6mm_H5mmSW8
1SW_DIP_x04Button_Switch_THT:SW_DIP_SPSTx04_Slide_9.78x12.34mm_W7.62mm_P2.54mmSW5
1SW_DIP_x08Button_Switch_THT:SW_DIP_SPSTx08_Slide_9.78x22.5mm_W7.62mm_P2.54mmSW3
1USB_BConnector_USB:USB_B_OST_USB-B1HSxx_HorizontalJ1

Questions

How big is the 8bit computer PCB?

It measures 246.4 × 185.4 mm and has 4 copper layers, 1.6 mm thick.

What parts does the 8bit computer use?

281 parts, built around the 74LS245SC, 74LS173SC, 74LS04PC and 74LS157PC. 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 8bit computer KiCad files?

From the tonygilkerson/8bit-computer repository on GitHub, at the commit this page was made from: the board is schematics/8bit-computer/8bit-computer.kicad_pcb and its schematic schematics/8bit-computer/8bit-computer-aeg.kicad_sch. PCBKit opens the board in the browser, with nothing to install.

Can I use the 8bit computer design in my own project?

Its repository states no licence, so its author keeps all rights: ask tonygilkerson before reusing the design.

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