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by ijor
Wed Nov 21, 2018 9:37 pm
Forum: MiSTer
Topic: FX CAST Atari ST core
Replies: 110
Views: 14129

Re: FX CAST Atari ST core

BBond007 wrote:Hopefully that info is useful...


Very useful! Many thanks
by ijor
Wed Nov 21, 2018 9:15 pm
Forum: MiSTer
Topic: controller ports: minimizing input lag
Replies: 27
Views: 1898

Re: controller ports: minimizing input lag

I hope we are not reopening a can of worms :) The USB input is pretty fast. Considering serial I/O input has to be added on a per-core basis and would likely be a hassle to keep coordinated, until someone can prove to me that there's an practical and appreciable (note: appreciable. A few ms is not a...
by ijor
Wed Nov 21, 2018 4:39 pm
Forum: MiSTer
Topic: Snes on FPGA may get sof file release for de 10 nano mister
Replies: 25
Views: 6029

Re: Snes on FPGA may get sof file release for de 10 nano mister

Is he the same developer that was asking the retro community to pay him big money to release the core as open source? Or that was somebody else?
by ijor
Wed Nov 21, 2018 4:37 pm
Forum: MiSTer
Topic: FPGA SNES source (srg320)
Replies: 52
Views: 6066

Re: FPGA SNES source (srg320)

Unfortunately the die shots don't seem good enough for die layout reverse engineering... Do you have the equipment to do what's needed? If so, I can send you some SNES machines, too. Sorry, I don't. For those cases that I reverse engineered the die layout, I either used die images provided by someb...
by ijor
Wed Nov 21, 2018 12:53 am
Forum: MiST
Topic: Genesis / Megadrive core ported to MiST
Replies: 832
Views: 105746

Re: Genesis / Megadrive core ported to MiST

I didn't know that document. Busy flag is not useless, it is actually very useful. The hardware works like this: The different operator information for each channel keeps moving in a cyclic shift register. There is only one point where you can write. So when you have data to write, you have to wait...
by ijor
Wed Nov 21, 2018 12:37 am
Forum: MiSTer
Topic: FPGA SNES source (srg320)
Replies: 52
Views: 6066

Re: FPGA SNES source (srg320)

I'm not sure if you were aware, but decaps already exist for the SNES chips (2/1/3): http://www.siliconpr0n.org/map/nintendo/. The SPC and DSP are missing, but the S-APU is there. Unfortunately the die shots don't seem good enough for die layout reverse engineering. The magnification is not high en...
by ijor
Mon Nov 19, 2018 10:01 pm
Forum: News & Announcements
Topic: FX68K Cycle accurate 68000 core
Replies: 31
Views: 5085

Re: FX68K Cycle accurate 68000 core

Does that mean that FX CAST comes with the same license as the other replay cores which doesn't allow it to be run on anything but replay hardware? Of course not. It will certainly be free to be used on MiST, Replay, or any other system for that matter. Jim probably meant FX68K (the 68000 part of t...
by ijor
Mon Nov 19, 2018 1:53 am
Forum: Hardware
Topic: Discovery Cartridge mystery addon device
Replies: 12
Views: 670

Re: Discovery Cartridge mystery addon device

Wasn't there a third party drive with a built-in track display?
by ijor
Mon Nov 19, 2018 1:50 am
Forum: News & Announcements
Topic: FX68K Cycle accurate 68000 core
Replies: 31
Views: 5085

Re: FX68K Cycle accurate 68000 core

This core is only a few percent bigger than tg68k and it just runs nicely. That's so cool ... Yeah. But to be fair to TK68K, I forgot that it can also be a 68020, and mine does not. TG68K would probably be smaller than it is if you remove all the 020 stuff. I've got a Myst, but I'm not a FPGA coder...
by ijor
Mon Nov 19, 2018 1:38 am
Forum: MiSTer
Topic: FX CAST Atari ST core
Replies: 110
Views: 14129

Re: FX CAST Atari ST core

While MIDI composing SW like Cubase and MIDI networking programs are finicky about things like that, I think plain MIDI playback could work fine. There are quite a lot of Atari games that have good music with appropriate MIDI synthesizer. Thank Eero, that's useful information. I would think though,...
by ijor
Fri Nov 16, 2018 11:16 pm
Forum: Kryoflux
Topic: Kryoflux & 5.25" floppies written by an ATARI810 drive
Replies: 1
Views: 677

Re: Kryoflux & 5.25" floppies written by an ATARI810 drive

Yes, you can read the top side with a standard drive. The exact command line depends on which kind of drive you have. If it's DD (40 tracks), or HD (80 tracks). You can probably find somebody nearby that would be able to read both sides of the disk. For this purpose, I recommend going to Atariage, a...
by ijor
Fri Nov 16, 2018 1:51 pm
Forum: News & Announcements
Topic: FX68K Cycle accurate 68000 core
Replies: 31
Views: 5085

Re: FX68K Cycle accurate 68000 core

What do you mean by DMA? Or do you mean the bus arbitration? Yes that's missing in tg68k and requires us to just stall the CPU by brute force. Yes, I meant bus arbitration. I found it surprising that's missing in TG68K because (I understand) all the other missing features are not used by the Amiga....
by ijor
Fri Nov 16, 2018 11:53 am
Forum: MiSTer
Topic: FX CAST Atari ST core
Replies: 110
Views: 14129

Re: FX CAST Atari ST core

JanniG wrote:Is a build with this sound fix already released?


Not yet. I'm holding the release because it fixes sound for some testers, but not for everybody. If you want to check it, please send me a PM.
by ijor
Fri Nov 16, 2018 12:34 am
Forum: MiSTer
Topic: Migrating Genesis core to FX68K
Replies: 25
Views: 1807

Re: Migrating Genesis core to FX68K

And from the manual, I've assert VPAn in INTACK, fixed the interrupts! Genesis core works with FX68K now! Titan2 demo is more perfect than before. Yeah, migrating is done. It works. Now need to tweak some signals and timings. Great! But where it is? I am probably missing something, but I can't find...
by ijor
Thu Nov 15, 2018 9:54 pm
Forum: MiSTer
Topic: Migrating Genesis core to FX68K
Replies: 25
Views: 1807

Re: Migrating Genesis core to FX68K

There's a DMA which can be initiated by the VDP, now it's only uses DTACK to hold the CPU. Probably the original way is to request the bus before the transfer. Yes, DTACK can't work on real hardware because the CPU will wait but it won't relinquish the bus. And this also applies when the Z80 uses t...
by ijor
Thu Nov 15, 2018 7:58 pm
Forum: MiSTer
Topic: Migrating Genesis core to FX68K
Replies: 25
Views: 1807

Re: Migrating Genesis core to FX68K

Will try to help integrating FX68K with the Genesis core. I would need first to familiarize myself with the core, and also with the Genesis hardware. But there doesn't seem to be much information about the arbiter. What's the timing of DTACK (how many wait states are inserted)? How DMA is implemente...
by ijor
Thu Nov 15, 2018 6:43 pm
Forum: News & Announcements
Topic: FX68K Cycle accurate 68000 core
Replies: 31
Views: 5085

Re: FX68K Cycle accurate 68000 core

From the size point of view, it is a bit larger than TG68k. It is expected to be larger. In first place because cycle accuracy takes a price, both in terms of size and performance. It requires quite some extra logic. In second place there are several 68K features that are not implemented by TG68k, ...
by ijor
Thu Nov 15, 2018 2:03 pm
Forum: News & Announcements
Topic: FX68K Cycle accurate 68000 core
Replies: 31
Views: 5085

Re: FX68K Cycle accurate 68000 core

I'm curious, are the ROMs (mem files) taken from the decapping you did? Or, if they're custom, do you have some tool to generate them rather than typing them in in binary? (in the dark ages before I had an assembler, I used Hex...) They are based on the die. I don't really have a clean automatic to...
by ijor
Thu Nov 15, 2018 1:53 pm
Forum: News & Announcements
Topic: FX68K Cycle accurate 68000 core
Replies: 31
Views: 5085

Re: FX68K Cycle accurate 68000 core

Sorgelig wrote:can you release it on github? Then there will be a central development repo for this IP, so you can get some pull requests if you don't mind.


Done:
https://github.com/ijor/fx68k
by ijor
Thu Nov 15, 2018 2:20 am
Forum: MiSTer
Topic: Migrating Genesis core to FX68K
Replies: 25
Views: 1807

Re: FX68K Cycle accurate 68000 core

Sorgelig wrote:In Genesis core DTACK is used for holding CPU.


Anybody made some traces with a logic analyzer on real Genesis hardware showing the clocks and the bus control signals? That could be very useful.
by ijor
Thu Nov 15, 2018 1:51 am
Forum: News & Announcements
Topic: FX68K Cycle accurate 68000 core
Replies: 31
Views: 5085

Re: FX68K Cycle accurate 68000 core

I moved all the posts specific to adapting Genesis core to the following thread: viewtopic.php?f=117&t=34736
by ijor
Thu Nov 15, 2018 1:48 am
Forum: MiSTer
Topic: Migrating Genesis core to FX68K
Replies: 25
Views: 1807

Migrating Genesis core to FX68K

This thread is a split from this one: viewtopic.php?f=28&t=34730

I know the subject is not really exclusive to MiSTer, but I thought this would be the best place. I can still move it somewhere else if needed.
by ijor
Thu Nov 15, 2018 1:30 am
Forum: MiST
Topic: Genesis / Megadrive core ported to MiST
Replies: 832
Views: 105746

Re: Genesis / Megadrive core ported to MiST

I think that the problem with DDR is non-consequitive reads. Like having to read from many different ROMs at the same "time". As you have to prepare the DDR banks again you lose precious clock cycles there. So, even if the memory bandwidth is great for reading data byte after byte; it may...
by ijor
Wed Nov 14, 2018 9:25 pm
Forum: MiST
Topic: Genesis / Megadrive core ported to MiST
Replies: 832
Views: 105746

Re: Genesis / Megadrive core ported to MiST

Surely the DDR bandwidth is more than enough. The problem might be the latency. The hardware interface (MPFE) is extremely efficient and the latency is much lower than I expected. But is not fully predictable because you don't control the hardware directly as you do with the SDRAM. Is the ROM access...
by ijor
Wed Nov 14, 2018 8:53 pm
Forum: MiSTer
Topic: Migrating Genesis core to FX68K
Replies: 25
Views: 1807

Re: FX68K Cycle accurate 68000 core

fpgaarcade wrote:note, I modified the top to bring out the PHI enables directly. I had to use a different synthesis tool as the old Xilinx software does not support SV


Hi Mike. Please check the download as it is slightly modified in relation to what you had. I'm not using a struct as an external port anymore.

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