2 layers335 × 218.6 mm
2 layers
ByteFrost
gilkeidar/ByteFrost5Software Tools for ByteFrost - A Breadboard 8-Bit Computer
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 36
- Nets
- 81
- Pads
- 260
- Tracks, vias
- 0, 0
- Routed
- Not yet
- KiCad
- KiCad 10.0 (file 20260206)
- Created
- 10 Apr 2022
- Updated
- 5 Aug 2026
Overview
ByteFrost is an open-source printed circuit board by gilkeidar, from the gilkeidar/ByteFrost repository on GitHub. It is a 2-layer board with 36 parts on 81 nets.
It is built around the 74HC374, 74HC00D and 74HC02, with the 74HC139D, 74HC14 and 74HC153D among its other parts. Its parts include 14 resistors, 14 ICs, 4 diodes and 4 switches. It belongs with the retro computing and games boards of this library.
Main components
8
74HC374
SOIC-20SOIC-20 New Arrivals ROHSTexas InstrumentsUncategorised
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 Gates74HC02
-- Logic Gates ROHSonsemiLogic Gates
74HC139D
SO-16-40℃~+125℃ 11ns@6.0V,50pF 160uA 2/4 2V~6V 74HC Decoder Single Supply SOIC-16 Signal Switches, Multiplexers, Decoders ROHSNexperiaSignal Switches / Encoders & Decoders / Multiplexers74HC14
SOP-14-40℃~+85℃ 1.9V、3.98V、4.4V、5.48V、5.9V 100mV、260mV、260mV 20uA 25ns@4.5V,50pF 2V~6V 6 74HC Noise suppression function Schmitt trigger SOP-14 Inverters ROHSJSMSEMIInverters
74HC153D
SOIC-16-40℃~+125℃ 160uA 2V~6V 44ns@4.5V,50pF 5.2mA 5.2mA 74HC 8/2 Multiplexer Output enable high-impedance Single Supply SOIC-16 Signal Switches, Multiplexers, Decoders ROHSNexperiaSignal Switches, Multiplexers, Decoders74HC32D
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 Gates74HC76S
SOP-160ns 0℃~+70℃ 1 1uA 2 20ns 20ns@5V,15pF 2V~6V 30MHz 5.2mA 5.2mA 74HC Series Falling Edge JK-Type Push-Pull Set and Reset SOP-16 Flip Flops ROHSGRFlip Flops
README
README.mdByteFrost
The Breadboard 8-bit CPU and Computer
Be sure to check out the YouTube channel for more in-depth explanations of how the ByteFrost works!
ByteFrost under development
In this Github repository are software tools for using the ByteFrost computer:
Assembler
Assembler program that converts Assembly code to ByteFrost machine language.
Note: The Assembler/ directory contains the deprecated assembler;
Assembler V2/ contains the new assembler, which also has new preprocessing
features, assembly instructions that can be translated to multiple ISA
instructions, and support for the new 16-bit memory address space expansion.
Display
Arduino code for the ByteFrost's display card (an Arduino Nano) for a 2004A LCD display.
Disk
Arduino code for the ByteFrost's disk controller (an Arduino MKR Zero) for a micro SD card that serves as the ByteFrost's disk.
Also included is software for handling ByteFrost disk files using the ByteFrost FileSystem (BFSv1), a very rudimentary filesystem with one root directory.
Documentation
Documentation for the ByteFrost computer. Includes hardware documentation (i.e. schematics) and software documentation (instruction set specifications, control signal lists, each instruction's micro-code and structure, and assembly syntax). For more documentation, see the wiki.
Microcode
Arduino code for programming the three microcode EEPROMs (using Ben Eater's EEPROM programmer as a basis).
Programs
Programs written in ByteFrost assembly that can be compiled using the assembler and run on the ByteFrost computer. Each program comes with the assembly code (.asm file), machine language compilation (.mlg file), and a binary file (.bin file).
Credits
The ByteFrost is a 2-person father-son project (by Gil and Ron Keidar) that we have been working on on-and-off (mostly during vacation between university quarters) for a few years (since March 2022).
My (Gil's) idea behind creating the ByteFrost was to work on a project that covers many abstraction layers in computer science (all of the way from the discrete logic layer to the application layer) and to, in the process, learn about and get hands-on experience with those layers.
Parts
36| Qty | Value | Footprint | References |
|---|---|---|---|
| 6 | 5.1K | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R106, R109, R110, R111, R401, R404 |
| 4 | 74HC374 | Package_DIP:DIP-20_W7.62mm_Socket | U1, U2, U3, U4 |
| 3 | 10K | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R101, R107, R108 |
| 3 | ICM7555xB | Package_SO:SOIC-8_3.9x4.9mm_P1.27mm | U101, U102, U401 |
| 2 | LED (red) | LED_THT:LED_D5.0mm | D102, D401 |
| 1 | 100 | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R102 |
| 1 | 17K | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R402 |
| 1 | 20K | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R105 |
| 1 | 212K | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R104 |
| 1 | 51K | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R403 |
| 1 | 74HC00 | Package_DIP:DIP-14_W7.62mm_Socket | U105 |
| 1 | 74HC02 | Package_DIP:DIP-14_W7.62mm_Socket | U6 |
| 1 | 74HC139 | Package_DIP:DIP-16_W7.62mm_Socket | U5 |
| 1 | 74HC14 | Package_DIP:DIP-14_W7.62mm_Socket | U402 |
| 1 | 74HC153 | Package_DIP:DIP-16_W7.62mm_Socket | U7 |
| 1 | 74HC32 | Package_DIP:DIP-14_W7.62mm_Socket | U104 |
| 1 | 74HC76 | Package_DIP:DIP-16_W7.62mm_Socket | U103 |
| 1 | Break | Button_Switch_THT:SW_PUSH_6mm_H7.3mm | SW102 |
| 1 | Cont. | Button_Switch_THT:SW_PUSH_6mm_H7.3mm | SW103 |
| 1 | LED (blue) | LED_THT:LED_D5.0mm | D103 |
| 1 | LED (green) | LED_THT:LED_D5.0mm | D101 |
| 1 | Reset | Button_Switch_THT:SW_PUSH_6mm_H7.3mm | SW401 |
| 1 | Single_Step | Button_Switch_THT:SW_PUSH_6mm_H7.3mm | SW101 |
Questions
What parts does the ByteFrost use?
36 parts, built around the 74HC374, 74HC00D, 74HC02 and 74HC139D. 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 ByteFrost KiCad files?
From the gilkeidar/ByteFrost repository on GitHub, at the commit this page was made from: the board is PCB/KiCAD/ByteFrost/ByteFrost.kicad_pcb and its schematic PCB/KiCAD/ByteFrost/ByteFrost.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the ByteFrost design in my own project?
Its repository states no licence, so its author keeps all rights: ask gilkeidar before reusing the design.
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