2 layers52.3 × 10.5 mm
StackLink
gusmanb/logicanalyzer
24 channel, 100Msps logic analyzer hardware and software
29 parts5.1kGPL-3.0
2 layers300 × 200 mm
CarbonZ80
Julesc013/abacus-21Project Codename: Abacus 2
- Size
- 300 × 200 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 29
- Nets
- 661
- Pads
- 810
- Tracks, vias
- 0, 0
- Routed
- Not yet
- KiCad
- KiCad 9.0 (file 20241229)
- Created
- 8 Oct 2024
- Updated
- 15 Jan 2026
Overview
CarbonZ80 is an open-source printed circuit board by Julesc013, from the Julesc013/abacus-2 repository on GitHub. It is a 2-layer board of 300 × 200 mm with 29 parts on 661 nets.
README
README.mdProject Codename: Abacus 2
Carbon A1 Minicomputer and Carbon Z1 Microcomputer
Project Abacus 2 Technical Reference (PDF)
Specifications
- CPU: Abacus 2 or Zilog Z80 (8-bit CISC)
- FPU: AMD Am9511 (Pre-IEEE 754)
- Clock: Up to 16 MHz (Crystal FM)
- RAM: Up to 640 KB (SRAM)
- ROM: Up to 128 KB (PROM)
- I/O: Up to 256 KB (Memory Mapped)
- TDD: Compact Cassette (KCS 240KB/hr)
- FDD: Floppy Disk (5.25" DSDD 360KB, 3.5" DSHD 1.44MB)
- Comms: Serial (RS-232), Parallel (DB-25)
- Video: Yamaha V9958 or TMS9918
- Audio: Yamaha OPNB or AY-3-8910
Design Showcase
System Architecture
16-bit CISC (Von Neumann)
Memory and I/O
Up to 640KB SRAM (8-bit bytes)
Up to 128KB PROM (8-bit bytes)
Up to 256KB memory mapped I/O.
Instruction Set
Abacus ISA (44 instructions) or Z80 ISA.
Integrated FPU (AMD AM9511)
Interrupt Handling
16 hardware int's, 110 software int's, 1 non-maskable int, 1 reset int; or Z80 Mode 2 interrupt scheme.
Video Output
VESA compatible (maybe)
System Firmware
Resident monitor, loaders, system routines, etc.
Physical Case
User Manual
Abacus 2 Technical Reference (PDF)
Directory Structure
├── archive Archived and old versions of files.
├── hardware Hardware design and circuitry.
│ ├── case Physical design of machine.
│ ├── cassette Cassette tape data storage.
│ ├── chipset Northbridge, southbridge, I/O, wait states, etc.
│ ├── floppy Floppy diskette data storage.
│ ├── instructions Instruction set architecture.
│ ├── interrupts Interrupt tables and circuits.
│ ├── memory Memory maps, wait states, DMA, etc.
│ ├── printer Parallel ports and printer communication.
│ ├── serial Serial ports and teletype communication.
│ ├── todo Todo lists and general notes.
│ └── video Video text and graphics output.
├── info General project information and metadata.
│ ├── datasheets Relevant datasheets.
│ ├── manual User and technical manuals for the system.
│ └── parts Parts lists and records.
├── schematics Schematics and technical drawings.
├── simulation Virtual simulation of processor.
│ ├── digital Implementation in Digital.
│ └── logisim Implementation in Logisim Evolution.
└── software Software, firmware, drivers, operating systems, etc.
├── assembler Assembler and linker.
├── basic Implementation of Microsoft 8K BASIC.Parts
29| Qty | Value | Footprint | References |
|---|---|---|---|
| 8 | HOLE | , , , , , , , | |
| 5 | Z84C20 | Package_DIP:DIP-40_W15.24mm_Socket | PIO0, PIO1, PIO2, PIO3, PIO4 |
| 1 | AM9511A | Package_DIP:DIP-24_W15.24mm_Socket | FPU0 |
| 1 | AS6C4008 | PCM_Package_DIP_AKL:DIP-32_W15.24mm_Socket | RAM0 |
| 1 | AT28C64B | Package_DIP:DIP-28_W15.24mm_Socket | ROM0 |
| 1 | BARREL_JACK_5.5x2.1 | Connector_BarrelJack:BarrelJack_Horizontal | PWR0 |
| 1 | BUS_SLOT1 | CarbonZ80_Library:8bISA_64pin | BUS0 |
| 1 | BUS_SLOT2 | CarbonZ80_Library:8bISA_64pin | BUS1 |
| 1 | BUS_SLOT3 | CarbonZ80_Library:8bISA_64pin | BUS2 |
| 1 | BUS_SLOT4 | CarbonZ80_Library:8bISA_64pin | BUS3 |
| 1 | DE9_SOCKET | Connector_Dsub:DSUB-9_Socket_Horizontal_P2.77x2.84mm_EdgePinOffset7.70mm_Housed_MountingHolesOffset9.12mm | COM0 |
| 1 | IDT6116 | Package_DIP:DIP-24_W15.24mm_Socket | RAM1 |
| 1 | MINI_DIN_KEYB | CarbonZ80_Library:Mini_DIN_6 | DIN0 |
| 1 | RAM_SIZE_SEL | Connector_PinHeader_2.54mm:PinHeader_1x03_P2.54mm_Vertical | SWT0 |
| 1 | Z84C00 | Package_DIP:DIP-40_W15.24mm_Socket | CPU0 |
| 1 | Z84C10 | Package_DIP:DIP-40_W15.24mm_Socket | DMA0 |
| 1 | Z84C30 | Package_DIP:DIP-28_W15.24mm_Socket | CTC0 |
| 1 | Z84C42 | Package_DIP:DIP-40_W15.24mm_Socket | SIO0 |
Questions
How big is the CarbonZ80 PCB?
It measures 300 × 200 mm and has 2 copper layers, 1.6 mm thick.
What parts does the CarbonZ80 use?
29 parts. 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 CarbonZ80 KiCad files?
From the Julesc013/abacus-2 repository on GitHub, at the commit this page was made from: the board is schematics/carbonATX/CarbonZ80/CarbonZ80.kicad_pcb and its schematic schematics/carbonATX/CarbonZ80/CarbonR80.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the CarbonZ80 design in my own project?
Its repository states no licence, so its author keeps all rights: ask Julesc013 before reusing the design.
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