Search found 857 matches

by JimDrew
Sat Jan 11, 2020 1:37 am
Forum: MiSTer
Topic: MISTer with RISC-V
Replies: 10
Views: 810

Re: MISTer with RISC-V

Fast emulators rely on dynamic recompilation (QEMU...). For example a simple busy loop as performance measurement can give misleading results. No type of DR (JIT) is necessary and you really don't want that anyways because it results in speedups and slow downs in performance that can be rather anno...
by JimDrew
Fri Jan 10, 2020 6:37 pm
Forum: MiSTer
Topic: MISTer with RISC-V
Replies: 10
Views: 810

Re: MISTer with RISC-V

LOL! I am guessing you have very little experience with software based emulations. There is no "trick". The performance is straight across the board. The reality is that FPGA based CPUs are going to be phased out for smaller and substantially cheaper RISC-V type systems. If you do have a s...
by JimDrew
Fri Jan 10, 2020 1:35 am
Forum: MiSTer
Topic: MISTer with RISC-V
Replies: 10
Views: 810

Re: MISTer with RISC-V

RISC-V soft core CPUs are the way to go for the future, greatly outrunning FPGAs in performance. This screenshot is from a FS-UAE Linux compiled experimental 1.5GHz RISC-V system. There are a few stability issues (Linux side) still that are being worked out, and apparently you can over-clock the sys...
by JimDrew
Mon Dec 09, 2019 12:59 am
Forum: MiSTer
Topic: Minimig RTG possible?
Replies: 124
Views: 21026

Re: Minimig RTG possible?

DigiPaint, DPaint AGA, Photon Paint, and any other program that relies on the fact that an Amiga screen will never be larger than 2MB in size. This affects scratch pages (screen copies), which can end up overlapping either non-existent or already used memory when not checking boundaries.
by JimDrew
Sat Dec 07, 2019 9:38 pm
Forum: MiSTer
Topic: SDRAM board
Replies: 458
Views: 161844

Re: SDRAM board

A right angle connector has a different impedance requirement than a straight (vertical) connector due to the different length of pins on one side of the connector. Although it doesn't seem like much, it does make a big difference in the layout.
by JimDrew
Sat Dec 07, 2019 2:38 am
Forum: MiSTer
Topic: SDRAM board
Replies: 458
Views: 161844

Re: SDRAM board

I agree it is a nightmare to try to do proper impedance matching, especially with a right angle connector. However, that doesn't answer the question of why there is a difference in the brands of chips? Maybe it would be better to use a 200MHz+ (2ns R/W time) BGA SDRAM module. There are a couple of d...
by JimDrew
Fri Dec 06, 2019 7:14 pm
Forum: SuperCard Pro Disk Copier
Topic: List of difficult to copy disks
Replies: 600
Views: 132685

Re: List of difficult to copy disks

Yes, with SCP you can just write the image to a disk. :)
by JimDrew
Fri Dec 06, 2019 7:12 pm
Forum: MiSTer
Topic: SDRAM board
Replies: 458
Views: 161844

Re: SDRAM board

OK, thanks for the explanation. What I don't understand is if you have two different brand chips that clearly will handle >=160MHz, why one fails at 160MHz and one doesn't.
by JimDrew
Fri Dec 06, 2019 12:46 am
Forum: MiSTer
Topic: Arcade cores
Replies: 904
Views: 205656

Re: Arcade cores

You can't expect a part to work outside of what its specifications are. Manufacturers change dies, masks, etc. and so what works today out of spec, may only work at spec with future versions. If you abide by the specifications given in the datasheet, then you should be guaranteed that any manufactur...
by JimDrew
Fri Dec 06, 2019 12:13 am
Forum: MiSTer
Topic: SDRAM board
Replies: 458
Views: 161844

Re: SDRAM board

With this version, 32MB Alliance based memory chips fail at 167MHz and 32MB Winbond based memory chips fail at 167MHz and 160MHz. All other memory test programs pass fine at 167MHz with the same Alliance and Winbond modules. So, this seems to be a step backwards.
by JimDrew
Thu Dec 05, 2019 11:54 pm
Forum: MiSTer
Topic: Arcade cores
Replies: 904
Views: 205656

Re: Arcade cores

You can't do that in the real world or you will open yourself up to headaches! :)
by JimDrew
Thu Dec 05, 2019 4:54 pm
Forum: MiSTer
Topic: SDRAM board
Replies: 458
Views: 161844

Re: SDRAM board

Probably a good idea, especially since the DE-10 Nano board itself plays a huge role in what memory modules will pass at different speeds.
by JimDrew
Thu Dec 05, 2019 12:33 am
Forum: MiSTer
Topic: Arcade cores
Replies: 904
Views: 205656

Re: Arcade cores

Winbond needs more time for RAS-CAS. Where Alliance is still working fine, Winbond fails already. Is this based on observations or datasheet information? It seems that when comparing the datasheets side by side there are only a few differences between the two chips in timing: Precharge to refresh/r...
by JimDrew
Thu Dec 05, 2019 12:30 am
Forum: MiSTer
Topic: Minimig RTG possible?
Replies: 124
Views: 21026

Re: Minimig RTG possible?

Well, the requirement is "generic". You are going to just have to extend the bus range for everything that uses CHIP memory. ALICE/DENISE/PAULA/GARY/BUSTER/etc. The WinUAE source code is available for download. sounds like i want this feature more than you. I am sure you do... I certainly...
by JimDrew
Wed Dec 04, 2019 5:59 pm
Forum: MiSTer
Topic: Arcade cores
Replies: 904
Views: 205656

Re: Arcade cores

I would be surprised if a chip type made a difference. My boards test fine at 167MHz. I have used both Alliance and Winbond brands on my boards (based on availability of the chips), so there is a mixture out there. I will grab this core and try it on both brands.
by JimDrew
Wed Dec 04, 2019 5:52 pm
Forum: MiSTer
Topic: Minimig RTG possible?
Replies: 124
Views: 21026

Re: Minimig RTG possible?

Well, the requirement is "generic". You are going to just have to extend the bus range for everything that uses CHIP memory. ALICE/DENISE/PAULA/GARY/BUSTER/etc. The WinUAE source code is available for download.
by JimDrew
Wed Dec 04, 2019 5:48 pm
Forum: MiSTer
Topic: SDRAM board
Replies: 458
Views: 161844

Re: SDRAM board

I believe the older test apps (black screen background, not the blue version) do test the SDRAM using the main frame work (I could be wrong here, I have not looked at any code). I have tested the Archie core and Minimig cores and they work fine. I have not setup a GBA or Neo Geo cores yet. I will do...
by JimDrew
Wed Dec 04, 2019 7:03 am
Forum: MiSTer
Topic: Minimig RTG possible?
Replies: 124
Views: 21026

Re: Minimig RTG possible?

CHIP memory resides at the start of memory 0x00000000 and goes to 0x0001FFFFF for 2MB of CHIP memory (for AGA machines). If you want more CHIP memory, just add memory beyond this. You will either need to patch the OS at boot time to extend the CHIP memory during config time, or you can make a simple...
by JimDrew
Wed Dec 04, 2019 6:11 am
Forum: MiSTer
Topic: Minimig RTG possible?
Replies: 124
Views: 21026

Re: Minimig RTG possible?

Well, I suppose that is true if you are running multiple programs at the same time that need CHIP memory for screens. You just can't use the extra CHIP memory for a single screen (beyond 2MB) or you start having odd copper list issues.

Hundreds of megs of memory is great to have for Mac emulations.
by JimDrew
Tue Dec 03, 2019 9:35 pm
Forum: MiSTer
Topic: SDRAM board
Replies: 458
Views: 161844

Re: SDRAM board

Well, today I received my mass produced DE-10 SDRAM boards. These all have -6TIN memory chips that were shipped from Alliance directly to the PCBA house I use (I setup the shipment). The samples I got were 1833 date code and worked up to 150MHz without any issues. The boards I received today have 18...
by JimDrew
Mon Dec 02, 2019 10:30 pm
Forum: Hardware
Topic: Preserving a floppy disk with a logic analyzer and a serial cable
Replies: 15
Views: 2715

Re: Preserving a floppy disk with a logic analyzer and a serial cable

I just saw this post for the first time! I have been a long time Saleae beta tester. I actually used the Logic device when developing SuperCard Pro to capture the signal that the board controls.
by JimDrew
Mon Dec 02, 2019 6:24 pm
Forum: MiSTer
Topic: USB Floppy support on MiSTer? Possible? Needed?
Replies: 15
Views: 2346

Re: USB Floppy support on MiSTer? Possible? Needed?

I have a Windows driver in the works that lets you read/write various disk types/file systems using the SCP board plugged into your PC. Basic USB commands can be used by anything that can access a USB device as a COM port or as an HID. Like I said, FX CAST for MiSTer already has flux level support u...
by JimDrew
Mon Dec 02, 2019 1:47 am
Forum: MiSTer
Topic: USB Floppy support on MiSTer? Possible? Needed?
Replies: 15
Views: 2346

Re: USB Floppy support on MiSTer? Possible? Needed?

The SuperCard Pro image file format has an open API and is very popular with emulation authors. WinUAE, FS-UAE, STeeM, and numerous other emulators for various computers systems all support .scp image files natively. FX CAST Atari ST emulator supports it with MiSTer already. There is plenty of sourc...
by JimDrew
Mon Dec 02, 2019 1:37 am
Forum: MiSTer
Topic: Minimig RTG possible?
Replies: 124
Views: 21026

Re: Minimig RTG possible?

No, 48MB is correct. Replay 1 supports 48MB of CHIP memory. Nothing can take advantage of it, but it's a good way to constrain memory speed for applications that can run too fast. There were a LOT of Amiga programs, especially in the A1000 and early A500 days that would simply do a memory read of ei...
by JimDrew
Sun Dec 01, 2019 5:33 pm
Forum: MiSTer
Topic: Minimig RTG possible?
Replies: 124
Views: 21026

Re: Minimig RTG possible?

As we found with Replay (where you could have up to 48MB of CHIP memory) is that many applications break when trying to use more than 2MB of CHIP memory.

Go to advanced search