Baffa-2 Homebrew Microcomputer

A project initially based on Grant Searle's "CP/M on breadboard" and heavily inspired by RC2014

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I started this project thinking about creating a machine with a Z80 CPU based on Grant Searle's project but I found so many possibilities that I keep expanding its hardware. I've been studying several old computers that used the Z80 CPU and I'm trying to adapt many of them to this project.

My goal is purely educational and for that, I created an emulator to run the original files (ROM and CP/M) before building my first prototype.

Basic Features:
* CPU: Z80 running at 7.3728 MHz
* Interface: Two high-speed serial ports capable of 115200 Bauds. (one running via wifi).
* Disk: 64MB or 128MB Compact Flash card support, containing 8 or 16 logical drives, respectively.
* RAM: 64K Byte
* ROM: 16K Byte, switched off when CP/M active.
* Resets: Both cold (full reset) and warm reset (used to return to CP/M prompt) circuitry
* CP/M support: 2.2 with included software.

Default Setup:

RomWBW Setup:

Colecovision Setup:

MSX1 Setup:

MSX2+ Setup:

Terminal Demonstration:

With AY3-8910 Soundboard:

With SN76489 Soundboard:

I am proud to say that this project is sponsored by PCBWay.

  • 1 × Backplane The Backplane was originally designed for Baffa-1 Project but intended to be used in many other projects.
  • 1 × Z80 CPU Board
  • 1 × Z80 SIO2 Dual Serial Board
  • 1 × Dual Clock Board
  • 1 × 64KB Ram Board

View all 9 components

View all 14 project logs

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John wrote 08/04/2022 at 17:41 point

Can this emulate the ZX81 or ZX Spectrum? That would be very interesting.

  Are you sure? yes | no

Augusto Baffa wrote 08/04/2022 at 19:01 point

Well, it's not an emulation because it uses the same real components but the answer is yes, sure! 

ZX81 set was designed last march and were the first boards I designed for Baffa-2 architecture but I prioritized other computers 'cos I assembled a ZX81 before this project. That will probably be the next set of boards I'm going to order and assemble... (check this out

ZX Spectrum I haven't been studying yet but is possible after have my ZX81 running. Even commodore 64 later since I've been working with 6502 CPU as well. For now, I'm studying the schematics from Apple ][+ computer and would be nice if I could design boards for it. In Brazil (where I live)  the most common computers in 80s were Apple][+(and IIe), ZX81/ZX Spectrum and MSX (the most popular).

  Are you sure? yes | no

John wrote 08/06/2022 at 10:06 point

Great! Looking forward to see your boards for the ZX81 (that was my first computer). I still remember how amazed I was when I found out the ROM programmer was using a single IC, the Z80A, for both the ZXBASIC and for composing the video output signal. Keep up the good work.

  Are you sure? yes | no

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