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A Megadrive core?

Posted: Mon May 28, 2018 4:53 pm
by SamusDrake
Would the Next's Spartan 6 FPGA be able to handle a Megadrive core? If so, how difficult would it be to set it up?

Cheers.

Re: A Megadrive core?

Posted: Mon Aug 12, 2019 7:09 pm
by intrepidis
I don't know for sure, but just governing from the specs of each machine I'd say no. The main reason: the MegaDrive CPU is 16-bit and has many more instructions (including variants such as move.w and move.l, etc). So I'm guessing the ZX Spectrum Next FPGA isn't powerful enough (i.e. have enough space) to handle it. I'd love to be proven wrong though. Unfortunately it'll probably be eight years before this post is answered, lol.

Re: A Megadrive core?

Posted: Mon Aug 12, 2019 7:41 pm
by biged
Might be a close-run thing. The Next has a Xilinx LX16, and the FPGAgen project seems to be near, or just over, the limit of fitting on a 20k Altera device. Let's say those two might be broadly comparable - everything depends on how well the respective synthesis tools manage.

I think the FPGAgen would be the starting point - there are many forks.

Re: A Megadrive core?

Posted: Tue Aug 13, 2019 4:25 am
by Tau Ceti
Could a Mister / DE-10 Nano handle a ZX Next Core?

Re: A Megadrive core?

Posted: Tue Aug 13, 2019 8:35 pm
by SevenFFF
For sure, the MISTer is a very beefy system. The Next core doesn’t yet have a SDRAM controller, as the Next uses SRAM, so it would need a fair bit of work and testing beyond simply synthesising for Altera.

Re: A Megadrive core?

Posted: Wed Aug 14, 2019 12:07 am
by dave18
For clarity, the response above is saying that Mister could easily handle the Next core but that the Next hardware has issues, especially around RAM types in supporting a Genesis core?

Re: A Megadrive core?

Posted: Wed Aug 14, 2019 12:10 am
by SevenFFF
No. The Next hardware has SRAM and the MISter hardware has DDR3 and optional SDR SDRAM.

The Next core is made for the Next hardware and SRAM. Not for the MISTer hardware. The Next core won’t run as designed on the MISTer without work on the core. An SDRAM controller would be part of the FPGA core program not the physical board.

Nothing to do with Genesis. I was answering the question about Next core running on MISTer hardware.

Re: A Megadrive core?

Posted: Wed Aug 14, 2019 12:21 am
by dave18
OK, thanks. In my limited experience memory timing (especially syncing memory reads to the video beam) is the difficult bit everything else is relatively easy. Makes sense that a change of memory type would create a lot of reworking of the core.