Last visit was: Sat Oct 23, 2021 11:05 am
It is currently Sat Oct 23, 2021 11:05 am



 [ 6 posts ] 
 Blitz 
Author Message
User avatar

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.

Image

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: 1640
Wow - no compromise!

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


Mon Apr 27, 2020 8:10 pm
User avatar

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.)

_________________
http://WilsonMinesCo.com/ 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 https://www.retrobrewcomputers.org/forum/index.php.

Rob


Thu Apr 30, 2020 8:36 pm
User avatar

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
 [ 6 posts ] 

Who is online

Users browsing this forum: CCBot and 0 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Jump to:  
Powered by phpBB® Forum Software © phpBB Group
Designed by ST Software