2 layers299.7 × 198.1 mm
Cisc-8
nailed-barnacle/Cisc-8-ttl-processor
A cut-down version of the 8080 processor using HCTTL and including a discrete ALU and instruction decoder
319 parts1MIT
2 layers
6502-electrical draft
jwvdvuurst/6502-boardA W65C02S computer board with bank-switched SRAM, a ROM monitor and Tiny BASIC, and a Raspberry Pi Pico USB terminal bridge.
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 53
- Nets
- 125
- Pads
- 416
- Tracks, vias
- 0, 0
- Routed
- Not yet
- KiCad
- KiCad 10.0 (file 20260206)
- Created
- 5 Nov 2026
- Updated
- 6 Nov 2026
Overview
6502-electrical draft is an open-source printed circuit board by jwvdvuurst, from the jwvdvuurst/6502-board repository on GitHub. It is a 2-layer board with 53 parts on 125 nets.
It is built around the 74HC00D, 74HC02 and 74HC08D, with the 74HC10D, 74HC138 and 74HC27D among its other parts. Its parts include 21 capacitors, 16 ICs, 12 resistors, 2 connectors and 1 switch. It belongs with the retro computing and games boards and the RP2040 boards of this library.
Main components
7
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 Gates74HC08D
SOP-14-40℃~+125℃ 1.5V~4.2V 1.9V、3.7V、5.2V 100mV、400mV 2 27ns@4.5V,50pF 2V~6V 2uA 4 5.2mA 5.2mA 500mV~1.8V 74HC Series AND Gate SOIC-14 Logic Gates ROHSNexperiaLogic Gates74HC10D
SO-14-40℃~+125℃ 1.5V~4.2V 16ns@6V,50pF 2V~6V 2uA 3 5.2mA 5.2mA 500mV~1.8V 74HC Series NAND Gate SOIC-14 Logic Gates ROHSNexperiaGates
74HC138
SOP-160℃~+70℃ 24ns@5.0V,16pF 2V~6V 3/8 5.2mA 5.2mA 5uA 74HC Decoder Reverse function Single Supply SOP-16 Signal Switches, Multiplexers, Decoders ROHSGRSignal Switches, Multiplexers, Decoders74HC27D
SOP-14-40℃~+125℃ 1.5V~4.2V 1.9V~2V、3.98V~4.32V、4.4V~4.5V、5.48V~5.81V、5.9V~6V 100mV、100mV、100mV、260mV、260mV 18ns@4.5V,50pF 2V~6V 2uA 3 3 5.2mA 5.2mA 500mV~1.8V 74HC Series NOR Gate SOIC-14 Logic Gates ROHSNexperiaGates74HCU04D
SO-14-40℃~+125℃ 1.7V~4.8V 1.8V、4V、5.5V 12ns@6V,50pF 200mV、260mV、500mV 2V~6V 2uA 300mV~1.2V 5.2mA 5.2mA 6 74HCU Push-pull StandardCMOS SO-14 Inverters ROHSNexperiaInverters
README
README.md6502-board
A W65C02S computer board with bank-switched SRAM, a ROM monitor and Tiny BASIC, and a Raspberry Pi Pico USB terminal bridge.
- Board design and hardware status
- ROM build, monitor commands, and BASIC
- Pico C firmware, build, and wiring
- ROM/Pico interface contract
- Electrical schematic PDF
The hardware is an electrical draft, not fabrication-ready. ROM firmware has been tested in emulation. Pico C firmware builds to UF2 and passes portable tests; physical hardware and USB/GPIO integration remain to be validated.
Agents
Agents must follow the rules, references, skills and agents described in the AI-hub [blocked] when this is available. See also AGENTS.md.
Parts
53| Qty | Value | Footprint | References |
|---|---|---|---|
| 2 | 27pF - crystal load | Capacitor_THT:C_Disc_D5.0mm_W2.5mm_P5.00mm | C2, C3 |
| 1 | 1.000MHz fundamental, CL=16pF | Crystal:Crystal_HC49-U_Vertical | Y1 |
| 1 | 100nF - EPROM bypass | Capacitor_THT:C_Disc_D5.0mm_W2.5mm_P5.00mm | C20 |
| 1 | 100nF - RESET_N power-on delay | Capacitor_THT:C_Disc_D5.0mm_W2.5mm_P5.00mm | C1 |
| 1 | 100nF - U1 CPU | Capacitor_THT:C_Disc_D5.0mm_W2.5mm_P5.00mm | C4 |
| 1 | 100nF - U10 NAND logic | Capacitor_THT:C_Disc_D5.0mm_W2.5mm_P5.00mm | C13 |
| 1 | 100nF - U12 3-input NAND logic | Capacitor_THT:C_Disc_D5.0mm_W2.5mm_P5.00mm | C14 |
| 1 | 100nF - U15 NOR logic | Capacitor_THT:C_Disc_D5.0mm_W2.5mm_P5.00mm | C15 |
| 1 | 100nF - U16 3-input NOR logic | Capacitor_THT:C_Disc_D5.0mm_W2.5mm_P5.00mm | C16 |
| 1 | 100nF - U18 AND logic | Capacitor_THT:C_Disc_D5.0mm_W2.5mm_P5.00mm | C17 |
| 1 | 100nF - U19 bus transceiver | Capacitor_THT:C_Disc_D5.0mm_W2.5mm_P5.00mm | C18 |
| 1 | 100nF - U2 VIA | Capacitor_THT:C_Disc_D5.0mm_W2.5mm_P5.00mm | C5 |
| 1 | 100nF - U20 EPROM | Capacitor_THT:C_Disc_D5.0mm_W2.5mm_P5.00mm | C19 |
| 1 | 100nF - U3 SRAM | Capacitor_THT:C_Disc_D5.0mm_W2.5mm_P5.00mm | C6 |
| 1 | 100nF - U4 address decoder | Capacitor_THT:C_Disc_D5.0mm_W2.5mm_P5.00mm | C7 |
| 1 | 100nF - U5 address mux | Capacitor_THT:C_Disc_D5.0mm_W2.5mm_P5.00mm | C8 |
| 1 | 100nF - U6 bank data mux | Capacitor_THT:C_Disc_D5.0mm_W2.5mm_P5.00mm | C9 |
| 1 | 100nF - U7 bank register | Capacitor_THT:C_Disc_D5.0mm_W2.5mm_P5.00mm | C10 |
| 1 | 100nF - U8 oscillator and inverters | Capacitor_THT:C_Disc_D5.0mm_W2.5mm_P5.00mm | C11 |
| 1 | 100nF - U9 I/O decoder | Capacitor_THT:C_Disc_D5.0mm_W2.5mm_P5.00mm | C12 |
| 1 | 10k - BE pull-up | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R5 |
| 1 | 10k - BUS_ACK idle pull-down | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R12 |
| 1 | 10k - BUS_DIR reset pull-down | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R11 |
| 1 | 10k - BUS_OE_N reset pull-up | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R9 |
| 1 | 10k - BUS_REQ reset pull-down | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R10 |
| 1 | 10k - IRQ_N pull-up | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R8 |
| 1 | 10k - NMI_N pull-up | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R4 |
| 1 | 10k - RDY_N pull-up | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R3 |
| 1 | 10k - RESET_N pull-up | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R7 |
| 1 | 10k - SO_N pull-up | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R6 |
| 1 | 10uF - 3V3 bulk bypass | Capacitor_THT:C_Disc_D5.0mm_W2.5mm_P5.00mm | C21 |
| 1 | 1M - HCU04 crystal feedback | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R1 |
| 1 | 1k - crystal drive limiter | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R2 |
| 1 | 74HC00 | Package_DIP:DIP-14_W7.62mm_Socket | U10 |
| 1 | 74HC02 | Package_DIP:DIP-14_W7.62mm_Socket | U15 |
| 1 | 74HC08 | Package_DIP:DIP-14_W7.62mm_Socket | U18 |
| 1 | 74HC10 | Package_DIP:DIP-14_W7.62mm_Socket | U12 |
| 1 | 74HC138 | Package_DIP:DIP-16_W7.62mm_Socket | U4 |
| 1 | 74HC138 - low-address I/O decode | Package_DIP:DIP-16_W7.62mm_Socket | U9 |
| 1 | 74HC157 - SRAM address mux | Package_DIP:DIP-16_W7.62mm_Socket | U5 |
| 1 | 74HC157 - bank write data mux | Package_DIP:DIP-16_W7.62mm_Socket | U6 |
| 1 | 74HC27 | Package_DIP:DIP-14_W7.62mm_Socket | U16 |
| 1 | 74HC273 - bank register | Package_DIP:DIP-20_W7.62mm_Socket | U7 |
| 1 | 74HCU04 | Package_DIP:DIP-14_W7.62mm_Socket | U8 |
| 1 | AS6C4008 (512K x 8; use lower 256K) | Package_DIP:DIP-32_W15.24mm_Socket | U3 |
| 1 | AT27LV256A 3.3V OTP EPROM - legacy DIP variant; verify sourcing | Package_DIP:DIP-28_W15.24mm_Socket | U20 |
| 1 | Pico external harness - do not power Pico from this header | Connector_PinHeader_2.54mm:PinHeader_1x14_P2.54mm_Vertical | J2 |
| 1 | REGULATED +3V3 INPUT - no regulator on board | Connector_PinHeader_2.54mm:PinHeader_1x02_P2.54mm_Vertical | J1 |
| 1 | RESET | Button_Switch_THT:SW_PUSH_6mm | SW1 |
| 1 | SN74HC245N - Pico/VIA bus transceiver | Package_DIP:DIP-20_W7.62mm_Socket | U19 |
| 1 | W65C02S6TPG-14 | Package_DIP:DIP-40_W15.24mm_Socket | U1 |
| 1 | W65C22S6TPG-14 | Package_DIP:DIP-40_W15.24mm_Socket | U2 |
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Questions
What parts does the 6502-electrical draft use?
53 parts, built around the 74HC00D, 74HC02, 74HC08D and 74HC10D. 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 6502-electrical draft KiCad files?
From the jwvdvuurst/6502-board repository on GitHub, at the commit this page was made from: the board is 6502-electrical-draft.kicad_pcb and its schematic 6502-board.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the 6502-electrical draft design in my own project?
Its repository states no licence, so its author keeps all rights: ask jwvdvuurst before reusing the design.