Search found 853 matches

by JimDrew
Sat Dec 07, 2019 9:38 pm
Forum: MiSTer
Topic: SDRAM board
Replies: 439
Views: 140771

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: 439
Views: 140771

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: 126447

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: 439
Views: 140771

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: 713
Views: 174347

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: 439
Views: 140771

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: 713
Views: 174347

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: 439
Views: 140771

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: 713
Views: 174347

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: 122
Views: 14376

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: 713
Views: 174347

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: 122
Views: 14376

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: 439
Views: 140771

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: 122
Views: 14376

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: 122
Views: 14376

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: 439
Views: 140771

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: 2174

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: 11
Views: 631

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: 11
Views: 631

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: 122
Views: 14376

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: 122
Views: 14376

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.
by JimDrew
Sun Dec 01, 2019 5:31 pm
Forum: MiSTer
Topic: SDRAM board
Replies: 439
Views: 140771

Re: SDRAM board

I am not sure. i would have to desolder a chip in order to check.
by JimDrew
Fri Nov 29, 2019 11:35 pm
Forum: MiSTer
Topic: Minimig RTG possible?
Replies: 122
Views: 14376

Re: Minimig RTG possible?

I can change the Amiga side driver as necessary. I have the source for it and did the initial testing for the Replay.

You will need to add Mikej's blitter VHDL.
by JimDrew
Fri Nov 29, 2019 11:33 pm
Forum: MiSTer
Topic: SDRAM board
Replies: 439
Views: 140771

Re: SDRAM board

I have 1822 date code chips from Digikey and they work fine. My mass produced boards have a 1844 date code.
by JimDrew
Sun Nov 24, 2019 6:49 am
Forum: MiSTer
Topic: FX CAST Atari ST core
Replies: 280
Views: 96941

Re: FX CAST Atari ST core

Works with my 64MB setup, but then again it also passes at 167MHz. Ijor, what is the max speed used by your SDRAM controller setup with FX CAST?

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