2 layers144.8 × 73.9 mm
Control
Robert-Riordan-UCD/8_Bit_CPU_PCB
PCB version of Ben Eaters 8-bit breadboard computer
68 partsCERN-OHL-P-2.0
2 layers58.6 × 38 mm
ProgramCounter
Robert-Riordan-UCD/8_Bit_CPU_PCBPCB version of Ben Eaters 8-bit breadboard computer
- Size
- 58.6 × 38 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 17
- Nets
- 24
- Pads
- 73
- Tracks, vias
- 109, 0
- Pours
- 2
- Routed
- Yes
- KiCad
- KiCad 8.0 (file 20240108)
- Created
- 22 Jul 2024
- Updated
- 15 Jan 2025
Overview
ProgramCounter is an open-source printed circuit board by Robert-Riordan-UCD, from the Robert-Riordan-UCD/8_Bit_CPU_PCB repository on GitHub, published under the CERN-OHL-P-2.0 licence. It is a 2-layer board of 58.6 × 38 mm with 17 parts on 24 nets, routed with 109 tracks and 0 vias.
It is built around the SN74HCT245N and CD74HC163E. Its parts include 4 resistors, 4 diodes, 2 ICs, 2 connectors and 1 capacitor. It belongs with the retro computing and games boards of this library.
Main components
2
SN74HCT245N
DIP-20-40℃~+85℃ 1 14ns@5.5V,50pF 4.5V~5.5V 6mA 6mA 74HCT 8 80uA Bidirectional Tri-State DIP-20 Buffers, Drivers, Receivers, Transceivers ROHSTexas InstrumentsBuffers, Drivers, Receivers, Transceivers
CD74HC163E
PDIP-16-55℃~+125℃ 1 24MHz 2V~6V 4 74HC Divide-by-2 Falling Edge Reset function、Cascade counter、Synchronous counting Synchronous Synchronous PDIP-16 Counters, Dividers ROHSTexas InstrumentsCounters, Dividers
README
README.md8-Bit PCB CPU
This is my version of Ben Eaters 8-bit breadboard SAP-1 CPU, converted to a PCB. I have made some minor changes as I could not find all of the components as listed in Ben's part list.
Video of the computer running
https://youtube.com/shorts/QNcSWgcGv9o?si=QzoUVq9Kj8X1f4Rs
Major Changes
Random Access Memory
- RAM IC's have been replaced with ATMega328-PU's. This should allow me to have persistant programs between power cycles.
License
CERN Open Hardware Licence Version 2 - Permissive
Parts
17| Qty | Value | Footprint | References |
|---|---|---|---|
| 4 | 220 | _DownloadFootprints:CF_series_Resistors_THT | R1, R2, R3, R4 |
| 4 | LED | LED_THT:LED_D5.0mm | D1, D2, D3, D4 |
| 1 | 0.1uF | Capacitor_THT:C_Disc_D5.0mm_W2.5mm_P2.50mm | C1 |
| 1 | CD74HC163E | _DownloadFootprints:binary_counter | U2 |
| 1 | Conn_01x05_Pin | Connector_PinHeader_2.54mm:PinHeader_1x05_P2.54mm_Vertical | J2 |
| 1 | Conn_01x10_Pin | Connector_PinHeader_2.54mm:PinHeader_1x10_P2.54mm_Vertical | J1 |
| 1 | SN74HCT245N | _DownloadFootprints:8x_tristate_transceiver | U1 |
The 13 most common of 17 parts.
Questions
How big is the ProgramCounter PCB?
It measures 58.6 × 38 mm and has 2 copper layers, 1.6 mm thick.
What parts does the ProgramCounter use?
17 parts, built around the SN74HCT245N and CD74HC163E. 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 ProgramCounter KiCad files?
From the Robert-Riordan-UCD/8_Bit_CPU_PCB repository on GitHub, at the commit this page was made from: the board is ProgramCounter/ProgramCounter.kicad_pcb and its schematic ALU/ALU.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the ProgramCounter design in my own project?
Its repository publishes it under the CERN-OHL-P-2.0 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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