4 layers55.5 × 65 mm
Jitx design
gusmanb/logicanalyzer
24 channel, 100Msps logic analyzer hardware and software
30 parts5.1kGPL-3.0
4 layers100 × 76.1 mm
OpenSpandPico2XL
paulczy/OpenSpandThe OpenSpand is an all-in-one expansion solution for Sinclair ZX81 computers and clones. Functionally very similar to ZXpand+, with more and extended functions.
- Size
- 100 × 76.1 mm
- Copper layers
- 4
- Thickness
- 1.6 mm
- Parts
- 30
- Nets
- 126
- Pads
- 386
- Tracks, vias
- 993, 108
- Pours
- 4
- Routed
- Yes
- KiCad
- KiCad 9.0 (file 20241229)
- Created
- 15 Sep 2026
- Updated
- 15 Sep 2026
Overview
OpenSpandPico2XL is an open-source printed circuit board by paulczy, from the paulczy/OpenSpand repository on GitHub. It is a 4-layer board of 100 × 76.1 mm with 30 parts on 126 nets, routed with 993 tracks and 108 vias.
It is built around the MCP23009-E/P. Its parts include 7 connectors, 5 capacitors, 5 resistors, 3 ICs and 3 diodes. It belongs with the RP2350 boards of this library.
Main components
1README
README.md
OpenSpand
The OpenSpand is an all-in-one expansion solution for Sinclair ZX81 computers and clones. Functionally very similar to ZXpand+, with more and extended functions.
Since the hardware design and software are open source, everything can be changed and expanded by others, making this a future proof ZX81 expansion. It is relatively cheap and easy to build. Others will hopefully find it easy to expand the functionality.
This is only a quick summary, read the rest in the OpenSpand_manual.md
Help can be found at:
https://www.sinclairzxworld.com/viewtopic.php?f=6&t=6123
or:
https://forum.tlienhard.com/phpBB3/viewtopic.php?t=4975
FEATURES
- 1-56KiB of RAM with software configurable mapping and size.
- SD card storage with transparent LOAD/SAVE integration.
- Embedded support commands in an overlay ROM for instant availability.
- Supports pseudo high resolution graphics.
- Supports true high resolution graphics, WRX.
- Supports user defined characters, CHR$64 or CHR$128.
- Single/dual emulated AY-3-8910 or YM2149 sound chip(s).
- Sampled stereo audio output.
- Joystick connector, standard 9-pin ATARI compatible. Several modes of direct reading. Also sends data via keyboard injection.
- Optional Bluetooth keyboard/gamepad support via a separate ESP32 satellite board on the I2C extension connector. See openspand-bt-satellite.
- Serial IO via extension connector.
- I2C IO via extension connector.
- ROM selectable: ZX80, ZX81, Big Bang X2 or from file.
- Bank switched RAM at 8-16k.
- A button to control soft, hard or factory reset.
- A button to enter the config menu.
- Configuration options via ZX81 keyboard & screen.
- Composite video output with backporch.
- Battery backed real-time clock with time and date.
- Firmware update via USB.
- Open source hardware and software!
The ZX81 internal ROM and RAM are always disabled, OpenSpand supplies all the memory needed.
Parts
30| Qty | Value | Footprint | References |
|---|---|---|---|
| 2 | 100n | Foot_1.2.1:C_Disc_D3.0mm_W1.6mm_P2.50mm | C2, C3 |
| 2 | 1k | Foot_1.2.1:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R1, R2 |
| 1 | |||
| 1 | 10V 10uF | Foot_1.2.1:C_1210_3225Metric_Pad1.33x2.70mm_HandSolder | C1 |
| 1 | 10V 1uF | Foot_1.2.1:C_1210_3225Metric_Pad1.33x2.70mm_HandSolder | C5 |
| 1 | 16V 47uF | Foot_1.2.1:C_1210_3225Metric_Pad1.33x2.70mm_HandSolder | C4 |
| 1 | 1N5817 | Foot_1.2.1:D_DO-41_SOD81_P10.16mm_Horizontal | D2 |
| 1 | 270R | Foot_1.2.1:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R4 |
| 1 | 470R | Foot_1.2.1:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R5 |
| 1 | 5VPIN5 | Foot_1.2.1:PinHeader_1x02_P2.54mm_Vertical | J6 |
| 1 | 5VPIN7 | Foot_1.2.1:PinHeader_1x02_P2.54mm_Vertical | J1 |
| 1 | 75R | Foot_1.2.1:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R3 |
| 1 | Config | Foot_1.2.1:SW_Tactile_SPST_Angled_PTS645Vx83-2LFS | SW0 |
| 1 | Conn_01x02 | Foot_1.2.1:ZX Video1 | VideoConnector1 |
| 1 | Conn_01x15_Pin | Foot_1.2.1:UDA1334 | J8 |
| 1 | DigitizedAudio | Foot_1.2.1:PinHeader_1x04_P2.54mm_Horizontal | J4 |
| 1 | External SPI | Foot_1.2.1:PinHeader_2x03_P2.54mm_Horizontal | J2 |
| 1 | GREEN | Foot_1.2.1:LED_D5.0mm | D0 |
| 1 | I2C_and_UART | Foot_1.2.1:PinHeader_2x04_P2.54mm_Horizontal | J5 |
| 1 | Joystick | Foot_1.2.1:DSUB-9_Male_Horizontal_P2.77x2.84mm_EdgePinOffset4.94mm_Housed_MountingHolesOffset7.48mm | Joy1 |
| 1 | MCP23009-E_P | Foot_1.2.1:DIP-18_W7.62mm | U2 |
| 1 | Pico2XL | Foot_1.2.1:P2350Pico2XL | U3 |
| 1 | RED | Foot_1.2.1:LED_D5.0mm | D1 |
| 1 | Reset | Foot_1.2.1:SW_Tactile_SPST_Angled_PTS645Vx83-2LFS | SW1 |
| 1 | SD-5-B | Foot_1.2.1:CUI_SD-5-B | SDCard0 |
| 1 | Video75 | Foot_1.2.1:PinHeader_1x02_P2.54mm_Vertical | J7 |
| 1 | ~ | Foot_1.2.1:ZX-EDGE64-2 | 0 |
| 1 | ~ | Foot_1.2.1:DS1307Module_BatteryUP | U1 |
Questions
How big is the OpenSpandPico2XL PCB?
It measures 100 × 76.1 mm and has 4 copper layers, 1.6 mm thick.
What parts does the OpenSpandPico2XL use?
30 parts, built around the MCP23009-E/P. 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 OpenSpandPico2XL KiCad files?
From the paulczy/OpenSpand repository on GitHub, at the commit this page was made from: the board is OpenSpand_HW/V1.22/OpenSpandPico2XL.kicad_pcb and its schematic OpenSpand_HW/V1.22/OpenSpandPico2XL.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the OpenSpandPico2XL design in my own project?
Its repository states no licence, so its author keeps all rights: ask paulczy before reusing the design.
Similar boards
- 4 layers23 × 53 mm
Easyduino STM32F103
Hanqaqa/Easyduino
Easily dive into different PCB KiCad designs of the most popular microcontroller devboards
30 parts755CERN-OHL-P-2.0 - 4 layers112.1 × 64 mm
- 4 layers15.2 × 19 mm
- 4 layers64.2 × 51.3 mm
- 4 layers64.5 × 70.1 mm
- 4 layers100 × 20 mm
Ocu2pciex8
inaxeon/ocu2pciex8
This repository contains the design files for a PCIe x4 (x8 physical) to OCuLink adapter I designed to solve some difficult PC build problems some time ago.
30 parts34 - 4 layers104.9 × 102.4 mm
