4 layers132.1 × 132.1 mm
2 layers100.3 × 99.7 mm
Tiny board
ifilot/bytecradle-65025Homebrew 6502-based computer
- Size
- 100.3 × 99.7 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 43
- Nets
- 78
- Pads
- 297
- Tracks, vias
- 1,167, 49
- Pours
- 2
- Routed
- Yes
- KiCad
- KiCad 9.0 (file 20241229)
- Created
- 8 Jan 2025
- Updated
- 18 Sep 2026
Overview
Tiny board is an open-source printed circuit board by ifilot, from the ifilot/bytecradle-6502 repository on GitHub, published under the GPL-3.0 licence. It is a 2-layer board of 100.3 × 99.7 mm with 43 parts on 78 nets, routed with 1,167 tracks and 49 vias.
It is built around the MAX232N and DS1813-5+. Its parts include 15 capacitors, 7 ICs, 6 resistors, 3 connectors and 3 switches. It belongs with the computers and single-board computers and retro computing and games boards and the FPGA and CPLD boards of this library.
Main components
2README
README.mdByteCradle 6502
The ByteCradle 6502 is a single-board computer (SBC) platform designed for understanding and experimenting with simple operating systems on 8-bit hardware. Built around the WDC 65C02 microprocessor, it provides a hands-on platform for studying system initialization, memory management, device interfacing, and file system handling.
[!NOTE]
The source code for the ByteCradle 6502 operating system for the Mini is found in a separate repository.
📋 Table of Contents
- BYTECRADLE 6502
- Overview
- Tier Comparison
- Obtaining PCBs
- Download ROMs
- License
- Contributing
- Acknowledgements
Overview
Both SBCs share a common design philosophy — to provide a straightforward and accessible 65C02 system, while exploring different levels of hardware capability.
Shared Components
- CPU: WDC 65C02
- I/O: WDC 65C51 Asynchronous Communications Interface Adapter (ACIA)
Tier Comparison
This project offers two tiers of single board computers (SBCs), each tailored to different levels of complexity and expandability:
- Tiny SBC (top): A simple, compact design ideal for learning or small embedded projects.
- Mini SBC (bottom): A more capable version with bank switching, SD card storage, and an expansion bus using the 65C22 Versatile Interface Adapter (VIA).
| Feature | Tiny SBC | Mini SBC |
|---|---|---|
| PCB | Two layer | Four layer |
| RAM | 32 KiB | 512 KiB (bank switched) |
| ROM | 32 KiB | 512 KiB (bank switched) |
| Bank Switching | No | Yes - 64 x 8 Kib banks |
| SD Card Support | No | Yes - Using WDC 65C22 VIA |
| I/O Interface | WDC 65C51 ACIA | WDC 65C51 ACIA |
| Expansion Options | Exposes system bus | Exposes system bus and VIA bus |
Obtaining PCBs
You can have the ByteCradle PCBs manufactured at any PCB fabrication service of your choice. However, for convenience and ease of ordering, we recommend using PCBWay.
The following links will take you directly to the shared projects on PCBWay, where you can order the boards:
[!NOTE]
These links direct you to the official project pages for the Mini and Tiny Boards on PCBWay.
Download ROMs
Below are the available ROM images for use with the ByteCradle single-board computers. These ROMs can be flashed onto your device depending on the board you are using.
- TinyROM
A lightweight ROM designed specifically for the Tiny Board. Ideal for minimal setups, testing, or basic 6502 development.
[!IMPORTANT]
Make sure to select the appropriate ROM for your board model. Flashing the incorrect ROM may result in system instability.
License
Software
All software (including ROM code, tools, and firmware) in this repository is licensed under the GNU General Public License v3.0.
This means:
- You are free to use, modify, and share the software.
- If you distribute modified versions, you must also release them under the GPLv3.
Hardware
All hardware design files (schematics, PCB layouts, bills of materials, etc.) are licensed under the CERN Open Hardware License v2 - Weakly Reciprocal (CERN-OHL-W).
This means:
- You may study, modify, manufacture, and distribute the hardware freely.
- If you distribute a modified version, you must share your changes under the same license.
Contributing
Contributions, ideas, and improvements are always welcome. Open an issue or submit a pull request to get involved!
Acknowledgements
We gratefully acknowledge PCBWay for their generous support in sponsoring the prototype PCB manufacturing of the Mini Board. Their assistance helped accelerate the development and testing of the hardware, and we appreciate their commitment to supporting open hardware projects.
Parts
43| Qty | Value | Footprint | References |
|---|---|---|---|
| 8 | 100nF | Capacitor_THT:C_Disc_D5.0mm_W2.5mm_P5.00mm | C1, C3, C5, C6, C7, C8, C9, C10 |
| 5 | 10uF | Capacitor_THT:CP_Radial_D5.0mm_P2.50mm | C2, C12, C13, C14, C15 |
| 4 | MountingHole | MountingHole:MountingHole_3.2mm_M3_DIN965_Pad_TopOnly | H1, H2, H3, H4 |
| 3 | 1k | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R1, R3, R4 |
| 1 | 1.8432 MHz | Crystal:Crystal_HC50_Vertical | Y1 |
| 1 | 100k | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R2 |
| 1 | 16 MHz | Oscillator:Oscillator_DIP-14 | X1 |
| 1 | 1M | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R5 |
| 1 | 220uF | Capacitor_THT:CP_Radial_D6.3mm_P2.50mm | C4 |
| 1 | 30pF | Capacitor_THT:C_Disc_D5.0mm_W2.5mm_P5.00mm | C11 |
| 1 | 560 | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R6 |
| 1 | 62256-55 | Package_DIP:DIP-28_W15.24mm_Socket | U4 |
| 1 | ATF22V10 | Package_DIP:DIP-24_W7.62mm_Socket | U5 |
| 1 | DS1813 | Package_TO_SOT_THT:TO-92 | U3 |
| 1 | LOGO | components:bytecradle-logo | G*** |
| 1 | MAX232 | Package_DIP:DIP-16_W7.62mm_Socket | U7 |
| 1 | NMI | Button_Switch_THT:SW_PUSH_6mm | SW3 |
| 1 | OSHW-Logo2_7.3x6mm_SilkScreen | Symbol:OSHW-Logo2_7.3x6mm_SilkScreen | G002 |
| 1 | POWER | LED_THT:LED_D5.0mm | D1 |
| 1 | RESET | Button_Switch_THT:SW_PUSH_6mm | SW2 |
| 1 | SST39SF010 | Package_DIP:DIP-32_W15.24mm_Socket | U2 |
| 1 | SW_SPDT | components:power_switch | SW1 |
| 1 | SYSTEM BUS | Connector_PinHeader_2.54mm:PinHeader_2x20_P2.54mm_Vertical | J3 |
| 1 | UART1 | Connector_Dsub:DSUB-9_Pins_Horizontal_P2.77x2.84mm_EdgePinOffset4.94mm_Housed_MountingHolesOffset4.94mm | J2 |
| 1 | USB_B | Connector_USB:USB_B_OST_USB-B1HSxx_Horizontal | J1 |
| 1 | W65C02 | Package_DIP:DIP-40_W15.24mm_Socket | U1 |
| 1 | W65C51NxP | Package_DIP:DIP-28_W15.24mm_Socket | U6 |
Questions
How big is the Tiny board PCB?
It measures 100.3 × 99.7 mm and has 2 copper layers, 1.6 mm thick.
What parts does the Tiny board use?
43 parts, built around the MAX232N and DS1813-5+. 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 Tiny board KiCad files?
From the ifilot/bytecradle-6502 repository on GitHub, at the commit this page was made from: the board is pcb/tiny-board/tiny-board.kicad_pcb and its schematic pcb/daughterboards/tinyboard-blinkenlight/tinyboard-blinkenlight.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Tiny board design in my own project?
Its repository publishes it under the GPL-3.0 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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