An AC6502 retro-style 8-bit computer based on the 65C02 microprocessor.
- Overview
- Architecture
- Systems
- Software
- Hardware
- Firmware
- CAD
- Production
- Schematics
- Libraries
- Bill of Materials
- Backplane
- Backplane Helper
- Backplane Pro
- Blinkenlights Card
- Breadboard Helper
- Clock Helper
- CPU Card
- CPU Card Pro
- DB25 Helper
- GPIO Breadboard Helper
- GPIO Card
- GPIO Helper
- Joystick Helper
- Keyboard Encoder Helper
- Keyboard Helper
- LCD Board
- LCD Card
- Mega Helper
- Memory Card
- Prototype Card
- PS2 Helper
- RAM Card
- RTC Card
- Serial Card
- Serial Card Pro
- Sound Card
- Storage Card
- Storage Card Pro
- VERA Helper
- VGA Card
- VGA Card Pro
- Video Card
- Video Card Pro
- License
The AC6502 ecosystem is a family of open-source, 65C02-based computers sharing a common architecture, memory map, and BIOS. Each computer in the family is purpose-built for a different use case but runs the same software and firmware.
The COB (Computer on a Backplane) is a full-featured modular desktop computer. It features a real 65C02 CPU, a backplane architecture with expandable card slots, up to 544KB RAM, composite or VGA video output, CompactFlash or SD storage, a real-time clock, and support for PS/2 keyboards, matrix keyboards, and Atari 2600-compatible joysticks.
All AC6502 computers share:
- CPU: 65C02 (or accurate emulation)
- Memory: 32KB RAM + 32KB ROM, with optional banked RAM expansion
- Memory Map: Standardized across the ecosystem — zero page, stack, I/O space ($8000–$9FFF), system ROM, and interrupt vectors at $FFFA–$FFFF
- Bus: 16-bit address bus, 8-bit bidirectional data bus, standard 65C02 control signals (RW, PHI2, RESET, IRQ, NMI, RDY, SYNC)
- BIOS: A common BIOS provides the kernel, monitor, and BASIC interpreter across all systems
| Project | Description |
|---|---|
| 6502-ACE | All-in-one Computer Experience — A single board computer |
| 6502-COB | Computer On a Backplane — Modular desktop computer with expandable card slots (YOU ARE HERE) |
| 6502-DEV | Development Environment Vehicle — Emulation-based dev system |
| 6502-KIM | Keypad Input Monitor - KIM-1 inspired minimal computer |
| 6502-VCS | Video Computer System — Cartridge-based retro gaming console |
| Project | Description |
|---|---|
| 6502-BIOS | The shared BIOS (kernel, monitor, BASIC) for all AC6502 computers |
| 6502-PRG | Template project for writing assembly language programs |
| 6502-CRT | Template project for writing assembly language cartridges |
| 6502-EMULATOR | Node.js-based AC6502 emulator |
| 6502-WEBULATOR | Web-based AC6502 emulator |
This repository contains KiCad 7.0+ PCB designs for the backplanes, cards, and helpers that make up the COB system.
Hardware/Backplane/ — Passive backplane providing 5 card slots with full bus interconnect across all slots.
Hardware/Backplane Pro/ — Enhanced backplane with integrated clock generation, reset circuitry, and power distribution plus 5 card slots.
Hardware/Backplane Helper/ — Adds additional card slots to expand the total backplane configuration up to 12 slots.
Hardware/CPU Card/ — Hosts the 65C02 CPU in a card form factor for backplane-based COB systems.
Hardware/CPU Card Pro/ — Hosts a 65816 16-bit CPU (backward-compatible with 65C02). (Untested)
Hardware/Memory Card/ — Provides 32KB SRAM and 32KB EEPROM with address decoding logic for COB systems using the CPU Card.
Hardware/RAM Card/ — 512KB banked RAM expansion organized as two 256KB banks with 256 × 1KB windows each.
Hardware/RTC Card/ — Real-time clock via Dallas DS1511Y with battery backup and 256 bytes of battery-backed SRAM.
Hardware/GPIO Card/ — General-purpose I/O via 65C22 VIA supporting keyboards, joysticks, timers, and custom devices.
Hardware/Serial Card/ — RS-232 serial communication via 65C51 ACIA and MAX232 level shifter.
Hardware/Serial Card Pro/ — Enhanced serial card with full modem control signals (DTR, DCD, DSR).
Hardware/VGA Card/ — VGA 640×480 video output via Raspberry Pi Pico running Pico9918 with TMS9918A-compatible graphics modes.
Hardware/VGA Card Pro/ — Fully programmable VGA output using Pi Pico with custom firmware. (Untested)
Hardware/Video Card/ — Composite video output via TMS9918A Video Display Processor with 16KB video RAM.
Hardware/Video Card Pro/ — Enhanced composite video card. (Untested)
Hardware/Sound Card/ — 3-voice SID audio output via ARMSID module with RCA line-level output.
Hardware/Storage Card/ — CompactFlash storage interface supporting up to 128GB via IDE-compatible protocol.
Hardware/Storage Card Pro/ — SD card (up to 32GB) and 16MB onboard SPI flash storage interface. (Untested)
Hardware/LCD Card/ — 16×2 character LCD display via 65C22 VIA in 4-bit or 8-bit mode.
Hardware/Blinkenlights Card/ — Visual bus monitoring with LEDs showing address bus (16), data bus (8), and control signals (8) in real time.
Hardware/Prototype Card/ — Blank prototyping area with integrated breadboard and full bus access headers.
Hardware/Keyboard Encoder Helper/ — ATmega1284p-based dual keyboard encoder supporting PS/2 keyboard and 8×8 matrix keyboard simultaneously via 65C22 VIA.
Hardware/PS2 Helper/ — ATmega328p-based PS/2 keyboard bridge that drives an MT8808 analog crosspoint switch to emulate a matrix keyboard for the 65C22 VIA.
Hardware/Keyboard Helper/ — 64-key matrix keyboard with Atari 2600-compatible joystick support.
Hardware/GPIO Helper/ — 8 buttons and 8 LEDs for testing and debugging GPIO Card connections.
Hardware/GPIO Breadboard Helper/ — Breadboard interface adapter for the GPIO Card.
Hardware/Joystick Helper/ — Atari 2600-style dual joystick connector and interface board.
Hardware/Clock Helper/ — Manual clock control providing single-step, free-run, and halt modes for debugging real CPU systems.
Hardware/DB25 Helper/ — GPIO to DB25 connector adapter for external device interfacing.
Hardware/Breadboard Helper/ — Exposes the full AC6502 bus to a breadboard for prototyping and experimentation.
Hardware/Mega Helper/ — Arduino Mega 2560 interface adapter for the AC6502 bus.
Hardware/LCD Board/ — 320×240 TFT LCD display (ILI9341) interfaced via 65C22 VIA. (Untested)
Hardware/VERA Helper/ — VERA FPGA video module adapter for the AC6502 bus.
This repository contains PlatformIO-based firmware for the COB system's microcontroller helpers.
Firmware/KEH Controller/
Firmware for the ATmega1284p on the Keyboard Encoder Helper. Provides:
- Simultaneous PS/2 keyboard and 8×8 matrix keyboard scanning
- ASCII conversion with modifier key support (Shift, Ctrl)
- Buffered, debounced input handling
- Parallel I/O to the AC6502 bus via 65C22 VIA
See Firmware/KEH Controller/README.md for setup and usage instructions.
Firmware/PS2 Keyboard Controller/
Firmware for the ATmega328p on the PS2 Helper. Provides:
- Interrupt-driven PS/2 keyboard scan code reading
- MT8808 analog crosspoint switch matrix control
- Make/break detection and extended scan code support
- Function key emulation via FN key combinations
See Firmware/PS2 Keyboard Controller/README.md for setup and usage instructions.
Firmware/STP Controller/
Firmware for the ATmega328p on the Storage Card Pro. Provides:
- Memory-mapped SPI controller for 6502 bus access
- Support for SD card, 16MB SPI flash, and external SPI devices
- Dual-speed SPI (4 MHz normal operation, 400 kHz initialization)
- PHI2-synchronized interface for reliable 6502 communication
See Firmware/STP Controller/README.md for setup and usage instructions.
CAD/
3D-printable enclosure parts and laser-cut top panels for the COB system.
Production/
JLCPCB-ready Gerber files and BOM/CPL for PCB fabrication and assembly.
Schematics/
PDF schematics for each board.
Libraries/
Shared KiCad symbol and footprint libraries used across all AC6502 hardware projects.
| Reference | Qty | Value | Description | DigiKey | Mouser |
|---|---|---|---|---|---|
| J1–J5 | 5 | 6502 Card Connector | Card Edge 2×20 | A31723-ND | 571-5-5530843-4 |
| J6, J7 | 2 | 6502 Bus | Bus Connector 2×20 | 732-5401-ND |
| Reference | Qty | Value | Description | DigiKey | Mouser |
|---|---|---|---|---|---|
| J1, J2 | 2 | 6502 Card Connector | Card Edge 2×20 | A31723-ND | 571-5-5530843-4 |
| J3 | 1 | 6502 Bus | Bus Connector 2×20 | 732-5401-ND |
| Reference | Qty | Value | Description | LCSC | DigiKey | Mouser |
|---|---|---|---|---|---|---|
| C1, C3–C14 | 13 | 100nF | Unpolarized capacitor | C49678 | ||
| C2 | 1 | 10uF | Polarized capacitor | C7171 | ||
| D1 | 1 | 1N5819 | Schottky Diode SOD-323F | C191023 | ||
| D2 | 1 | LED | LED 0805 | C2297 | ||
| J1 | 1 | PWR_SW | JST XH 1×2 | 455-2247-ND | ||
| J2 | 1 | USB-C | USB 2.0 Type-C Receptacle | C2988369 | ||
| J3 | 1 | RESET_SW | JST XH 1×2 | 455-2247-ND | ||
| J4 | 1 | CLOCK_ENBL_SW | JST XH 1×2 | 455-2247-ND | ||
| J5–J9 | 5 | 6502 Card Connector | Card Edge 2×20 | A31723-ND | 571-5-5530843-4 | |
| J10 | 1 | 6502 Bus | Bus Connector 2×20 | |||
| Q1 | 1 | SS8050 | NPN Transistor SOT-23 | C2150 | ||
| R1 | 1 | 1M | Resistor | C17514 | ||
| R2 | 1 | 47k | Resistor | C17713 | ||
| R3 | 1 | 1k | Resistor | C17513 | ||
| R4 | 1 | 10k | Resistor | C17414 | ||
| R5, R6 | 2 | 5.1k | Resistor | C27834 | ||
| R7 | 1 | 330 | Resistor | C17630 | ||
| SW1 | 1 | Reset | Push Button | C318884 | ||
| U1 | 1 | LM555xM | Timer SOIC-8 | C7593 | ||
| X1 | 1 | OCXO-14 | Crystal Oscillator DIP-14 |
| Reference | Qty | Value | Description | LCSC |
|---|---|---|---|---|
| C1–C4 | 4 | 100nF | Unpolarized capacitor | C49678 |
| D1–D25 | 25 | LED | LED 0805 | C2297 |
| D26, D27 | 2 | LED | LED 0805 | C2295 |
| D28–D30 | 3 | LED | LED 0805 | C2296 |
| D31, D32 | 2 | LED | LED 0805 | C2293 |
| R1–R32 | 32 | 330 | Resistor | C17630 |
| U1, U2, U4 | 3 | 74HC573 | 8-bit Latch SOIC-20 | C5608 |
| U3 | 1 | 74HC04 | Hex Inverter SOIC-14 | C5590 |
| Reference | Qty | Value | Description | DigiKey |
|---|---|---|---|---|
| J1 | 1 | 6502 Bus | Bus Connector 2×20 | 732-5401-ND |
| J2, J3 | 2 | Pin Header | Pin Header 1×20 |
| Reference | Qty | Value | Description |
|---|---|---|---|
| C1 | 1 | 100nF | Capacitor |
| D1, D2 | 2 | LED | LED 3mm |
| J1 | 1 | IO | Pin Header 1×5 |
| R1–R5 | 5 | 1k | Resistor |
| R6–R8 | 3 | 330 | Resistor |
| SW1, SW2 | 2 | XKB5858-Z | DPDT Toggle Switch |
| SW3 | 1 | XKB5858-W | DPDT Toggle Switch |
| U1 | 1 | 74HC74 | Dual D Flip-flop DIP-14 |
| Reference | Qty | Value | Description | LCSC |
|---|---|---|---|---|
| C1 | 1 | 100nF | Unpolarized capacitor | C49678 |
| J2 | 1 | Pin Header | Pin Header 1×2 | |
| J3 | 1 | EXP | Pin Header 2×5 | |
| R1–R6 | 6 | 1k | Resistor | C17513 |
| U1 | 1 | 65C02 | CPU DIP-40 |
| Reference | Qty | Value | Description | LCSC |
|---|---|---|---|---|
| C1–C4 | 4 | 100nF | Unpolarized capacitor | C49678 |
| J2 | 1 | BANK ADDR | Pin Header 2×5 | |
| J3 | 1 | EXP | Pin Header 2×4 | |
| R1–R6 | 6 | 1k | Resistor | C17513 |
| U1 | 1 | 65C816 | CPU DIP-40 | |
| U2 | 1 | 74HC00 | Quad NAND SOIC-14 | C5586 |
| U3 | 1 | 74HC245 | Octal Bus Transceiver TSSOP-20 | C5626 |
| U4 | 1 | 74HC573 | 8-bit Latch SOIC-20 | C5608 |
| Reference | Qty | Value | Description | DigiKey |
|---|---|---|---|---|
| J1 | 1 | PORT A | GPIO Connector 2×6 | |
| J2 | 1 | PORT B | GPIO Connector 2×6 | |
| J3 | 1 | KEYBOARD | DB-25 Connector (Male) | 609-1505-ND |
| Reference | Qty | Value | Description |
|---|---|---|---|
| J1 | 1 | PORT A | GPIO Connector 2×6 |
| J2 | 1 | PORT A | Pin Header 1×12 |
| J3 | 1 | PORT B | Pin Header 1×12 |
| J4 | 1 | PORT B | GPIO Connector 2×6 |
| Reference | Qty | Value | Description | LCSC |
|---|---|---|---|---|
| C1, C2 | 2 | 100nF | Unpolarized capacitor | C49678 |
| D1 | 1 | Schottky Diode | Schottky Diode DO-35 | |
| J2 | 1 | IO SELECT | Pin Header 2×8 | |
| J3 | 1 | PORT A | GPIO Connector 2×6 | |
| J4 | 1 | PORT B | GPIO Connector 2×6 | |
| U1 | 1 | 74HC138 | Decoder SOIC-16 | C5602 |
| U2 | 1 | 65C22 | VIA DIP-40 |
| Reference | Qty | Value | Description | DigiKey |
|---|---|---|---|---|
| D1–D8 | 8 | LED | LED 3mm | |
| J1 | 1 | PORT A | GPIO Connector 2×6 | |
| J2 | 1 | PORT B | GPIO Connector 2×6 | |
| R1–R8 | 8 | 1k | Resistor | |
| R9–R16 | 8 | 330 | Resistor | |
| SW1–SW8 | 8 | Push Button | Push Button 6mm | 2223-TS02-66-50-BK-160-LCR-D-ND |
| Reference | Qty | Value | Description | DigiKey |
|---|---|---|---|---|
| J1 | 1 | PORT | GPIO Connector 2×6 | |
| J2 | 1 | DB-9 Male | DB-9 Connector (Male) | 609-1481-ND |
| R1–R8 | 8 | 1k | Resistor |
| Reference | Qty | Value | Description | DigiKey |
|---|---|---|---|---|
| C1, C4 | 2 | 100nF | Capacitor | |
| C2, C3 | 2 | 22pF | Capacitor | |
| J1 | 1 | PORT B | GPIO Connector 2×6 | |
| J2 | 1 | PORT A | GPIO Connector 2×6 | |
| J3 | 1 | PS/2 KEYBOARD | 6-pin Mini-DIN | |
| J4 | 1 | KEYBOARD | DB-25 Connector (Male) | 609-1505-ND |
| R1 | 1 | 1k | Resistor | |
| U1 | 1 | ATmega1284-P | MCU DIP-40 | |
| Y1 | 1 | 16 MHz | Crystal HC49-U | 3155-16M20P2/49US-ND |
| Reference | Qty | Value | Description | DigiKey |
|---|---|---|---|---|
| J1, J2 | 2 | JOYSTICK | DB-9 Connector (Male) | 609-1481-ND |
| J3, J4 | 2 | JOYSTICK | GPIO Connector 2×6 | |
| J5, J6 | 2 | PORT | GPIO Connector 2×6 | |
| J7 | 1 | KEYBOARD | DB-25 Connector (Male) | 609-1505-ND |
| R1–R16 | 16 | 1k | Resistor | |
| SW1–SW67 | 67 | Cherry MX | Key Switch |
| Reference | Qty | Value | Description |
|---|---|---|---|
| C1–C4 | 4 | 100nF | Capacitor |
| D1, D2 | 2 | Schottky Diode | Schottky Diode DO-35 |
| J1 | 1 | 6502 Bus | Bus Connector 2×20 |
| J2 | 1 | IO SELECT | Pin Header 2×8 |
| J3 | 1 | HVSYNC | Pin Header 1×1 |
| R1 | 1 | 10k | Resistor |
| U1 | 1 | 65C22 | VIA DIP-40 |
| U2 | 1 | Adafruit 2.8" TFT | TFT LCD Module |
| U3 | 1 | 74HC138 | Decoder DIP-16 |
| Reference | Qty | Value | Description | LCSC |
|---|---|---|---|---|
| C1, C2 | 2 | 100nF | Unpolarized capacitor | C49678 |
| D1 | 1 | Schottky Diode | Schottky Diode DO-35 | |
| J2 | 1 | GPIO | Pin Header 1×7 | |
| J3 | 1 | IO SELECT | Pin Header 2×8 | |
| R1 | 1 | R | Resistor | |
| U1 | 1 | 65C22 | VIA DIP-40 | |
| U2 | 1 | LCD-16X2 | 16×2 Character LCD | |
| U3 | 1 | 74HC138 | Decoder SOIC-16 | C5602 |
| VR1 | 1 | 10k | Potentiometer |
| Reference | Qty | Value | Description |
|---|---|---|---|
| A1 | 1 | Arduino Mega 2560 | Arduino Mega 2560 R3 Shield |
| J1 | 1 | 6502 Bus | Bus Connector 2×20 |
| Reference | Qty | Value | Description | LCSC |
|---|---|---|---|---|
| C1–C5 | 5 | 100nF | Unpolarized capacitor | C49678 |
| J2 | 1 | Pin Header | Pin Header 2×2 | |
| J3 | 1 | Pin Header | Pin Header 1×2 | |
| R1, R2 | 2 | 1k | Resistor | C17513 |
| U1, U2, U5 | 3 | 74HC00 | Quad NAND SOIC-14 | C5586 |
| U3 | 1 | AS6C62256 | SRAM DIP-28 | |
| U4 | 1 | AT28C256 | EEPROM DIP-28 |
| Reference | Qty | Value | Description | LCSC |
|---|---|---|---|---|
| C1–C3 | 3 | 100nF | Unpolarized capacitor | C49678 |
| J2 | 1 | Bus Header | Pin Socket 2×20 | |
| J3 | 1 | EXP | Pin Header 2×4 | |
| U1 | 1 | 74HC138 | Decoder SOIC-16 | C5602 |
| Reference | Qty | Value | Description |
|---|---|---|---|
| C1–C3 | 3 | 100nF | Disc Capacitor |
| C4, C5 | 2 | 22pF | Disc Capacitor |
| J1 | 1 | PORT A | GPIO Connector 2×6 |
| J2 | 1 | PORT B | GPIO Connector 2×6 |
| J3 | 1 | PS/2 | Mini-DIN 6-pin |
| J4 | 1 | JOYSTICK | GPIO Connector 2×6 |
| R1–R9 | 9 | 1k | Resistor |
| U1 | 1 | MT8808 | Analog Matrix Switch DIP-28 |
| U2 | 1 | ATmega328 | MCU DIP-28 |
| Y1 | 1 | 16 MHz | Crystal |
| Reference | Qty | Value | Description | LCSC |
|---|---|---|---|---|
| C1–C7 | 7 | 100nF | Unpolarized Capacitor | C49678 |
| J2 | 1 | LATCH EN | Pin Header 1×2 | |
| J3 | 1 | Conn_02x08 | Pin Header 2×8 | |
| J4 | 1 | BANK ADDR | Pin Header 2×5 | |
| R1, R2 | 2 | 10k | Resistor | C17414 |
| U1 | 1 | AS6C4008 | SRAM DIP-32 | |
| U2 | 1 | 74HC573 | Octal Latch SOIC-20 | C5608 |
| U3, U6 | 2 | 74HC00 | Quad NAND SOIC-14 | C5586 |
| U4 | 1 | 74HC21 | Dual 4-input AND SOIC-14 | C75398 |
| U5 | 1 | 74HC30 | 8-input NAND SOIC-14 | C19818870 |
| U7 | 1 | 74HC138 | Decoder SOIC-16 | C5602 |
| Reference | Qty | Value | Description | LCSC | DigiKey |
|---|---|---|---|---|---|
| BT1 | 1 | BAT-HLD-001-THM | Coin Cell Battery Holder | ||
| C1–C3 | 3 | 100nF | Unpolarized Capacitor | C49678 | |
| D1 | 1 | Schottky Diode | Schottky Diode DO-35 | ||
| J2 | 1 | AUX | Pin Header 1×6 | ||
| J3 | 1 | INT Select | Pin Header 1×3 | ||
| J4 | 1 | Conn_02x08 | Pin Header 2×8 | ||
| R1 | 1 | 1k | Resistor | C17513 | |
| U1 | 1 | DS1511Y | RTC DIP-28 | DS1511Y+-ND | |
| U2, U3 | 2 | 74HC138 | Decoder SOIC-16 | C5602 |
| Reference | Qty | Value | Description | LCSC | DigiKey |
|---|---|---|---|---|---|
| C1, C6, C8 | 3 | 100nF | Unpolarized Capacitor | C49678 | |
| C2–C5 | 4 | 1uF | Unpolarized Capacitor | C28323 | |
| C7 | 1 | 22pF | Unpolarized Capacitor | C1804 | |
| D1 | 1 | Schottky Diode | Schottky Diode DO-35 | ||
| J2 | 1 | DB9 FEMALE (DCE) | DB-9 Connector (Female) | 609-1487-ND | |
| J3 | 1 | Conn_02x08 | Pin Header 2×8 | ||
| J4 | 1 | CTS EN | Pin Header 1×3 | ||
| R1 | 1 | 1M | Resistor | C103906 | |
| U1 | 1 | MAX232 | RS-232 Driver/Receiver | C59824 | |
| U2 | 1 | 74HC138 | Decoder SOIC-16 | C5602 | |
| U3 | 1 | 6551 | ACIA DIP-28 | ||
| Y1 | 1 | 1.8432 MHz | Crystal |
| Reference | Qty | Value | Description | LCSC | DigiKey |
|---|---|---|---|---|---|
| C1, C2, C11, C13 | 4 | 100nF | Unpolarized Capacitor | C49678 | |
| C3–C10 | 8 | 1uF | Unpolarized Capacitor | C28323 | |
| C12 | 1 | 22pF | Unpolarized Capacitor | C1804 | |
| D1 | 1 | Schottky Diode | Schottky Diode DO-35 | ||
| J2 | 1 | DB9 MALE (DTE) | DB-9 Connector (Male) | 609-1481-ND | |
| J3 | 1 | Conn_02x08 | Pin Header 2×8 | ||
| J4 | 1 | DCD Select | Pin Header 1×3 | ||
| R1 | 1 | 1M | Resistor | C103906 | |
| U1, U2 | 2 | MAX232 | RS-232 Driver/Receiver | C59824 | |
| U3 | 1 | 74HC138 | Decoder SOIC-16 | C5602 | |
| U4 | 1 | 6551 | ACIA DIP-28 | ||
| Y1 | 1 | 1.8432 MHz | Crystal |
| Reference | Qty | Value | Description | LCSC | DigiKey |
|---|---|---|---|---|---|
| C1, C2 | 2 | 2.2nF | Unpolarized Capacitor | C28260 | |
| C3, C5 | 2 | 100nF | Unpolarized Capacitor | C49678 | |
| C4 | 1 | 1uF | Unpolarized Capacitor | C28323 | |
| J2 | 1 | VDD | JST XH 1×2 | ||
| J3 | 1 | AUDIO | RCA Connector | PJRAN1X1U02X | |
| J5 | 1 | Conn_02x08 | Pin Header 2×8 | ||
| R1 | 1 | 1k | Resistor | C17513 | |
| U1 | 1 | 6581 | SID Chip DIP-28 | ||
| U2 | 1 | 74HC138 | Decoder SOIC-16 | C5602 |
| Reference | Qty | Value | Description | LCSC |
|---|---|---|---|---|
| C1, C2 | 2 | 100nF | Unpolarized Capacitor | C49678 |
| D1 | 1 | LED | Activity LED 0805 | C2297 |
| J2 | 1 | Conn_02x08 | Pin Header 2×8 | |
| J3 | 1 | Compact Flash | CompactFlash Connector | C444350 |
| J4 | 1 | ACT LED | JST XH 1×2 | |
| R1–R4 | 4 | 1k | Resistor | C17513 |
| R5, R6 | 2 | 330 | Resistor | C17630 |
| U1 | 1 | 74HC00 | Quad NAND SOIC-14 | C5586 |
| U2 | 1 | 74HC138 | Decoder SOIC-16 | C5602 |
| Reference | Qty | Value | Description | LCSC | DigiKey |
|---|---|---|---|---|---|
| C1–C4, C7, C8 | 6 | 100nF | Unpolarized Capacitor | C49678 | |
| C5, C6 | 2 | 22pF | Disc Capacitor | C107114 | |
| C9, C10 | 2 | 1uF | Unpolarized Capacitor | C28323 | |
| D1 | 1 | LED | Activity LED 0805 | C2297 | |
| J1 | 1 | ACT LED | JST XH 1×2 | ||
| J3 | 1 | SPI | Pin Header 1×6 | ||
| J4 | 1 | SD CARD | SD Card Connector | C569097 | |
| J5 | 1 | Conn_02x08 | Pin Header 2×8 | ||
| R1, R2 | 2 | 330 | Resistor | C17630 | |
| R3, R4 | 2 | 1k | Resistor | C17513 | |
| U1 | 1 | TXS0108EPW | Level Shifter TSSOP-20 | C17206 | |
| U2 | 1 | ATmega328 | MCU DIP-28 | ||
| U3 | 1 | W25Q128JVS | Flash Memory SOIC-8 | C97521 | |
| U4 | 1 | 74HC138 | Decoder SOIC-16 | C5602 | |
| U5 | 1 | LP2985-3.3 | LDO Regulator 3.3V SOT-23-5 | C95414 | |
| Y1 | 1 | 16 MHz | Crystal | 3155-16M20P2/49US-ND |
| Reference | Qty | Value | Description | DigiKey |
|---|---|---|---|---|
| C1, C2 | 2 | 100nF | Disc Capacitor | |
| D1 | 1 | Schottky Diode | Schottky Diode DO-35 | |
| J1 | 1 | 6502 Bus | Bus Connector 2×20 | |
| J2 | 1 | VERA Module | Pin Header 2×12 | |
| J3 | 1 | Audio L | RCA Connector | PJRAN1X1U02X |
| J4 | 1 | Audio R | RCA Connector | PJRAN1X1U03X |
| J5 | 1 | INT Select | Pin Header 1×3 | |
| J6 | 1 | Conn_02x08 | Pin Header 2×8 | |
| U1, U2 | 2 | 74HC138 | Decoder DIP-16 |
| Reference | Qty | Value | Description | LCSC |
|---|---|---|---|---|
| C1, C2 | 2 | 100nF | Unpolarized Capacitor | C49678 |
| D1 | 1 | Schottky Diode | Schottky Diode DO-35 | |
| J2 | 1 | INT Select | Pin Header 1×3 | |
| J3 | 1 | Conn_02x08 | Pin Header 2×8 | |
| U1 | 1 | Pico9918A | VDP Module DIP-40 | |
| U2, U3 | 2 | 74HC138 | Decoder SOIC-16 | C5602 |
| Reference | Qty | Value | Description | LCSC |
|---|---|---|---|---|
| C1–C6 | 6 | 100nF | Unpolarized Capacitor | C49678 |
| D1 | 1 | Schottky Diode | Schottky Diode DO-35 | |
| J2 | 1 | VGA | DB-15 VGA Connector (Female) | |
| J3 | 1 | INT Select | Pin Header 1×3 | |
| J4 | 1 | Conn_02x08 | Pin Header 2×8 | |
| Q1 | 1 | BSS138 | N-Channel MOSFET SOT-23 | C78284 |
| R1, R2, R4, R7 | 4 | 1k | Resistor | C17513 |
| R3, R6 | 2 | 2.2k | Resistor | C17520 |
| R5, R8 | 2 | 470 | Resistor | C17710 |
| R9 | 1 | 820 | Resistor | C17837 |
| R10 | 1 | 390 | Resistor | C17655 |
| R11, R12 | 2 | 22 | Resistor | C17561 |
| U1 | 1 | SN74LVC4245APWR | Octal Bus Transceiver TSSOP-24 | C7859 |
| U2 | 1 | 74LVC245 | Octal Bus Transceiver TSSOP-20 | C6082 |
| U3 | 1 | Raspberry Pi Pico | MCU Module | |
| U4 | 1 | 74HC138 | Decoder SOIC-16 | C5602 |
| U5 | 1 | 74LVC138 | Decoder SOIC-16 | C6061 |
| Reference | Qty | Value | Description | LCSC | Mouser | DigiKey |
|---|---|---|---|---|---|---|
| C1, C2 | 2 | 32pF | Disc Capacitor | C107114 | ||
| C3–C10 | 8 | 100nF | Unpolarized Capacitor | C49678 | ||
| D1 | 1 | Schottky Diode | Schottky Diode DO-35 | |||
| FB1 | 1 | BLM41PG600SN1L | Ferrite Bead 1806 | C85844 | ||
| J1 | 1 | INT Select | Pin Header 1×3 | |||
| J3 | 1 | Conn_02x08 | Pin Header 2×8 | |||
| J4 | 1 | VIDEO | RCA Connector | PJRAN1X1U04X | ||
| Q1 | 1 | 2N4401 | NPN BJT TO-92 | |||
| R1 | 1 | 470 | Resistor | C17710 | ||
| R2 | 1 | 75 | Resistor | C17820 | ||
| U1 | 1 | TMS9918A | VDP DIP-40 | |||
| U2, U5, U6 | 3 | 74HCT574 | 8-bit Register SOIC-20 | C6001 | ||
| U3, U4 | 2 | 74HC138 | Decoder SOIC-16 | C5602 | ||
| U7 | 1 | AS6C62256 | SRAM DIP-28 | |||
| U8 | 1 | 74HCT04 | Hex Inverter SO-14 | C672096 | ||
| Y1 | 1 | 10.738635 MHz | Crystal | 774-MP107-E |
| Reference | Qty | Value | Description | LCSC | Mouser | DigiKey |
|---|---|---|---|---|---|---|
| C1, C2 | 2 | 20pF | Disc Capacitor | C105173 | ||
| C3–C10 | 8 | 100nF | Unpolarized Capacitor | C49678 | ||
| D1 | 1 | Schottky Diode | Schottky Diode DO-35 | |||
| FB1 | 1 | BLM41PG600SN1L | Ferrite Bead 1806 | C85844 | ||
| J1 | 1 | VIDEO | RCA Connector | PJRAN1X1U04X | ||
| J2 | 1 | SERIAL | Pin Header 1×4 | |||
| J3 | 1 | INT Select | Pin Header 1×3 | |||
| J5 | 1 | Conn_02x08 | Pin Header 2×8 | |||
| Q1 | 1 | 2N4401 | NPN BJT TO-92 | |||
| R1, R2 | 2 | 4.7k | Resistor | |||
| R3 | 1 | 470 | Resistor | C17710 | ||
| R4 | 1 | 75 | Resistor | C17820 | ||
| R5 | 1 | 1k | Resistor | |||
| U1, U4 | 2 | 74HC157 | Quad 2-to-1 Mux SOIC-16 | C6823 | ||
| U2, U5 | 2 | 74HC166 | Shift Register SOIC-16 | C473363 | ||
| U3 | 1 | ATmega1284-P | MCU DIP-40 | |||
| U6 | 1 | 74HC138 | Decoder SOIC-16 | C5602 | ||
| VR1, VR2 | 2 | 10k | Potentiometer | |||
| Y1 | 1 | 14.31818 MHz | Crystal | 774-MP107-E |
Hardware designs are released under the CERN Open Hardware Licence Version 2 – Permissive.
Firmware is released under the MIT License.