ZXGATE - ZX81, TRS-80, Speccy on a Chip

[Hornpipe2]

In my sporadic Google-research about the various system-on-a-chip I ran across the following site:

http://zxgate.sourceforge.net/

 

Pretty cool stuff there. Those of you with a Xilinx FPGA setup can build a brand-new ZX81, ZX-Spectrum, Jupiter ACE or TRS-80 with an FPGA and maybe an external RAM chip. It's all open-source VHDL code. I would LOVE to build all four of the machines there but I have no way to program an FPGA. Drat.

 

There is also the Minimig, an Amiga chipset in an FPGA (you supply the RAM and the 68000): http://en.wikipedia.org/wiki/Minimig but this probably deserves its own thread : ) FPGA Arcade also has some really cool recreations of other arcade parts in FPGAs, including a full Odyssey2, a Vic-20, and a Colecovision on a chip! Take a look at http://home.freeuk.net/fpgaarcade/index.htm

 

retromicro.com is looking at ways to do some classic Atari computers-on-a-chip but it doesn't look like anything has surfaced there.

Edited October 17, 2007 by Hornpipe2

[JamesD]

There are a lot more machines that have been put on FPGA than that. If you look around further you will find there are mostly or fully working versions of the C64, Apple II, Thomson MO5, Tandy CoCo 3, Atari ST, Amstrad CPC, Sharp MZ700, NEC PC-8001, MSX... and that's just off the top of my head.

There is also VHDL source for the Oric's custom chip but I don't know if it's ever been tested and a complete machine implemented on a chip. If it works the other chips have already been implemented.

 

There are several other machines that should be easy to implement since chips they are based on have already been implemented. The EACA Colour Genie, Acorn Atom, MC-1000 (Brazil), Laser or Dick Smith VZ-200/300... the list is pretty long.

 

Don't count on the zxgate machines being cycle accurate. Speccy fans are trying to work that out for 100% compatibility for a Spectrum clone.

 

BTW, check out this page. Mark has been busy porting many of these projects to a common platform.

http://members.iinet.net.au/~msmcdoug/

Edited October 17, 2007 by JamesD

[Hornpipe2]

There are a lot more machines that have been put on FPGA than that. If you look around further you will find there are mostly or fully working versions of the C64, Apple II, Thomson MO5, Tandy CoCo 3, Atari ST, Amstrad CPC, Sharp MZ700, NEC PC-8001, MSX... and that's just off the top of my head.

Totally awesome. I had been looking for an Apple II recently. (And yes, I know at least about the C-One / C64 DTV - is there another C64-on-a-chip that is open source?)

[JamesD]

The only one I could find quickly. It's for the C1 but could be ported to other hardware.

http://www.syntiac.com/fpga64.html

 

Another Apple II (not open source yet):

http://www.mirrow.com/FPGApple/

 

I've seen several Apple II projects but most were "converting schematics" and had nothing to show.

[Tom]

I'd love to play around with FPGAs aswell. I've got a Spartan-3 Board from Digilent with an XC3S200, the thing is just, I have absolutely no idea what's possible with an FPGA of this size...the board itself is neat. It has switches, LEDs, four 7 Segment LED Displays, VGA/RS232/PS2 plugs (only plugs...logic would go into the FPGA) and 1MB SRAM.