Sharp X68000 Code

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Gehstock
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Sharp X68000 Code

Postby Gehstock » Fri Jan 27, 2017 11:55 am

if someone search for a new Project
http://fpga8801.seesaa.net/category/247823249-1.html
Last edited by Gehstock on Fri Feb 24, 2017 7:33 pm, edited 1 time in total.

retrorepair
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Re: Sharp X68000 Code

Postby retrorepair » Fri Jan 27, 2017 4:16 pm

Looks like it's currently active but since I don't read Japanese I can't tell how far along it is. Very, very interesting though!

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Estrayk
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Re: Sharp X68000 Code

Postby Estrayk » Fri Jan 27, 2017 5:13 pm

Will be a dream a X68000 in the MIST.
・Falcon 030+FPU 14mb CosmosEX・Atari MegaSTE 4Mb CosmosEX・Atari STe 4Mb GotekHxC+Satan・Amiga A600 Vampire V2・Amiga A1200 030/50・MIST・

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mfro
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Re: Sharp X68000 Code

Postby mfro » Fri Jan 27, 2017 6:16 pm

retrorepair wrote:Looks like it's currently active but since I don't read Japanese I can't tell how far along it is. Very, very interesting though!


At least it synthesizes without any error.

Might be a bit too heavy for the MiST, however. The core fills up 68% logic on a Cyclone V ...

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jotego
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Re: Sharp X68000 Code

Postby jotego » Fri Jan 27, 2017 10:06 pm

It says they are working now on the floppy disk emulation.

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Re: Sharp X68000 Code

Postby Gehstock » Sat Jan 28, 2017 7:27 am

mfro wrote:
retrorepair wrote:Looks like it's currently active but since I don't read Japanese I can't tell how far along it is. Very, very interesting though!


At least it synthesizes without any error.

Might be a bit too heavy for the MiST, however. The core fills up 68% logic on a Cyclone V ...
Last edited by Gehstock on Fri Feb 24, 2017 7:33 pm, edited 1 time in total.

retrorepair
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Re: Sharp X68000 Code

Postby retrorepair » Thu Feb 09, 2017 6:49 am

That's very cool! Wonder if jotego's YM2151 would fit in there too?

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jaildesigner
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Re: Sharp X68000 Code

Postby jaildesigner » Thu Feb 09, 2017 9:01 am

This core would be like a dream come true!

But I wonder what will happen with all the different refresh rates it can handle, I think it uses 15, 24 and 31Khz

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Newsdee
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Re: Sharp X68000 Code

Postby Newsdee » Thu Feb 09, 2017 12:16 pm

I'll take whatever comes before thinking about extra features :D

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Re: Sharp X68000 Code

Postby Sorgelig » Thu Feb 09, 2017 1:01 pm

Gehstock wrote:Use Revision F68k_DE0 needs some work but Fits

It doesn't. Not enough M9K memory blocks.

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Re: Sharp X68000 Code

Postby Gehstock » Thu Feb 09, 2017 1:06 pm

But we have SDRAM

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Re: Sharp X68000 Code

Postby Sorgelig » Thu Feb 09, 2017 1:36 pm

DE with Cyclone V has 3Mbit RAM(M10K). Our Cyclone III has 600KBit RAM(M9K). Actually not only total amount of bits important but total amount of blocks as well because blocks cannot be shared. Or FPGA has 66 blocks, while Cyc V has ~300 blocks.

Thus.. don't expect it ported. With such high graphics specs of X68000 i believe a lot of FPGA RAM used.

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Re: Sharp X68000 Code

Postby Sorgelig » Thu Feb 09, 2017 1:40 pm

FPGA RAM is more versatile. It's dual ported static RAM (SRAM) with much higher speed and zero latency. SDRAM need around 10 clock cycles to get the data. You can compare yourself.

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Re: Sharp X68000 Code

Postby Sorgelig » Thu Feb 09, 2017 1:53 pm

Don't want to let you down, but check X68000 hw.
It has 3 separate RAM systems:
1) main RAM up to 12MB - can emulate it with MiST SDRAM
2) 16KB SRAM - this is easy to emulate with FPGA RAM
3) VRAM: 1056 KB - here we have a problem. May be it's possible to emulate with MiST SDRAM if bandwidth is higher than sum of Main RAM and VRAM. But expect a lot of work here.

I'm not familiar with X68000. I think, that time the only RAM they could use is Asynchronous DRAM as a main RAM. It means you need around 10x times faster SDRAM to emulate Async DRAM (but since CPU doesn't access the RAM at every cycle, timings can be relaxed). I have no idea what they've used for VRAM. Probably also Async. DRAM.
When i was making SAM Coupe core i had similar problem because video buffer of SAM Coupe can be anywhere in the whole RAM. But since SAM Coupe has single RAM system shared on original HW, i had much more relaxed conditions.. With X68000 case, there are 2 separate RAM systems which will be much harder (if possible at all) to fit into single SDRAM chip.
Even Amiga has single RAM system - so don't compare it to X68000.

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Re: Sharp X68000 Code

Postby Gehstock » Thu Feb 09, 2017 2:49 pm

So I wrote that yes it still work needed, but Logic Cells we have enough. And Remember we have a Genesis-Beta-Core Now, nothing is Impossible.

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Re: Sharp X68000 Code

Postby phoboz » Wed Jun 21, 2017 7:32 am

Thid should be a feasable project now for the MiSTer, since it also uses the Cyclone V FPGA?

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Re: Sharp X68000 Code

Postby Sorgelig » Wed Jun 21, 2017 10:40 am

Yeah, FPGA in MiSTer is bigger than in FPGA where X68000 targeted.


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