Author Topic: Yet another FPGA emulator...  (Read 2602 times)

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Offline ralferoo

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Yet another FPGA emulator...
« on: 00:03, 15 January 12 »
I mentioned offhandedly in someone else's post that I was also working on an FPGA emulator. I'm not particularly intending to release this any time soon, as it's still someway off being finished, but I though I'd give a quick progress report... :)

This really is quite a grassroots project. I'm doing this as an exercise in learning VHDL, so I'm doing everything from scratch except the Z80 core and I'm tempted to have a go at that when everything else is working as it seems to consume over 60% of the FPGA gates (and I'm using a fairly massive 250K gate chip)!

As well as not using existing implementations apart from the CPU, and just working from datasheets and information pages here at cpcwiki and grimware, I've managed to make my life even harder by buying an FPGA board that has nothing except a few LEDs and buttons. In fact, the only concession it has to being handy is a USB-serial port, so at least I've been able to debug and upload code using a serial port! So I've had to build external boards for everything including RAM, flash ROM and SCART adaptor, etc.

Anyway, today was my first big milestone... I added a PS/2 keyboard and so I can now run things in BASIC! In order to get this up to CPC 464 level, I just need to fill in the sound generation part of the AY-8912 as I only did the bare minimum to get the keyboard working.

If you want to take a look at the pictures and commentary, there's a blog at ralferoo.blogspot.com which I'm updating most days with each little step forward. Here's something to whet your appetite:
  (click for bigger)
« Last Edit: 00:19, 15 January 12 by ralferoo »

Offline Bryce

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Re: Yet another FPGA emulator...
« Reply #1 on: 00:13, 15 January 12 »
Impressive work Ralf, you never mentioned that when we met up a few weeks ago. Were you keeping it a secret?

Bryce.

Offline ralferoo

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Re: Yet another FPGA emulator...
« Reply #2 on: 00:27, 15 January 12 »
I only actually started in the Christmas holidays! I've had these FPGA boards knocking around for about 18 months, but I couldn't use them as the drivers require a 32-bit version of Windows and I'm upgraded to 64-bit and didn't have a downgrade disk.

Anyway, for some reason I decided to dust off the FPGA kit, found someone at work with the right version of Vista so I could downgrade and I started experimenting at the start of December, about a week before freemac announced his project. By that point I was still messing around with video output. But, as Magnus Magnusson always says, "I've started so I'll finish..." :)

Offline TFM

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Re: Yet another FPGA emulator...
« Reply #3 on: 01:02, 15 January 12 »
Great work!!!
TFM of FutureSoft
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