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Joined: Sat Aug 10, 2019 1:13 am
Posts: 7
Hello everyone,

I've finished putting together a repository for one of my long-term projects, Blitz.
Blitz is a Motorola 68030 based homebrew that I've spent nearly the last 3 years working on.


For a more detailed rundown, more pictures, and all the project files, check out the GitHub repository

Some specs:

  • Motorola 68030 @25-50MHz + 68882 FPU
  • 4MB of static RAM + 64MB DRAM
  • 512k of Flash ROM
  • VT8242 based PS/2 Keyboard interface
  • AIC37C65CL based Floppy interface
  • ATA hard disk interface
  • 3x 8-bit ISA expansion slots
  • Single XC9572XL CPLD doing all logic

The board is designed loosely following the microATX form-factor, which means it can be installed in a standard PC case, should you want to do that.
Blitz runs a homebrew OS I wrote called G-DOS, which includes useful things like a command shell and memory monitor.
For more information about G-DOS specifically, visit the other topic I started in the software board.

Some parts remain are unfinished, like the DRAM interface, which I have yet to get working correctly.
I consider Blitz to be "complete" for the sake of my own sanity so I can focus on other projects, though I do still plan to work on it further to polish it up.
Any updates and stuff will of course be posted here.

Mon Apr 27, 2020 5:35 pm WWW

Joined: Wed Jan 09, 2013 6:54 pm
Posts: 1647
Wow - no compromise!

How do you arrange to use the SRAM vs the DRAM?

Mon Apr 27, 2020 8:10 pm
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Joined: Sat Aug 10, 2019 1:13 am
Posts: 7
I went for a relatively large amount of SRAM onboard since i knew getting the DRAM working was going to take a while.
The SRAM is mapped starting at the base of memory extending upwards to 0x400000, and the DRAM is mapped in a nonconsecutive bank starting at 0xC000000.
Once the DRAM is working, I'll likely move the malloc heap into there to take advantage of all the extra memory.
Since that frees up a lot of the SRAM, I might be worth copying the OS there on boot to take advantage of the single bus cycle memory access; much faster compared to the flash.

Mon Apr 27, 2020 8:35 pm WWW

Joined: Tue Dec 11, 2012 8:03 am
Posts: 285
Location: California
If you do another, note the 4Mx8 5V 10ns SRAM modules I offer, shown on the front page of my website, linked below. I suspect you want 3.3V though. I could assemble it if you want to provide the chips, or I could provide just the bare boards with the .1uF capacitors already installed. (They're tricky to get right, which is why I don't provide kits.)

_________________ lots of 6502 resources

Tue Apr 28, 2020 4:16 am WWW

Joined: Thu Apr 30, 2020 4:45 am
Posts: 1
Very cool! Is that a VGA port in the upper right? If so, what are you using to drive that? Is there a serial port on the board?

You should also post this (and your software) over at


Thu Apr 30, 2020 8:36 pm
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Joined: Sat Aug 10, 2019 1:13 am
Posts: 7
That is a VGA port!
The large chip next to it is a PIC24FJ256, which has hardware LCD controller that i planned to hijack.
I never got around to implementing it, since I had started an FPGA based solution around the same time.
It was removed from the latest revision board, since I had success with using a CGA card for video instead.

There is no serial port onboard, since it was much easier to just add a PC serial card to on of the ISA slots.

I've actually already requested access to the retrobrew forums, but am still waiting on a response. I'll definitely post there when I get the chance.

Thu Apr 30, 2020 11:51 pm WWW
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