04 April 2018, 09:48 | #1 |
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A4000 112MB Memory hack
Hi
Here's Meutoxo's improved version of Meutoxo's memory hack :-) You can: a) use 1x 64MB simm and use 64MB with fastramsey (requires the 64MB jed) b) use 2x 64MB simm and use 112MB without fastramsey c) Use a 128MB simm to use 112MB All 64/112MB of memory are autoconfig. I've done the hack successfully in two different A4000D (desktop and micronik) and also in my A4000T (let me know if it works for you as we only tested it on my own A4kT) so I will provide support here, don't bug Meutoxo as he's very busy. I have not attached the doc file and just the PDF as it made the archive too big. If you do any change to the pcb or jed files please share here. BTW, I've noticed that the new A4000+ motherboard seems to lack the empty GAL area, in that case you will need the PCB on top of ramsey just like A4000T owners. Enjoy Last edited by Crumb; 04 April 2018 at 12:18. |
04 April 2018, 14:26 | #2 |
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http://www.amibay.com/showthread.php...our-A4000-mobo
http://www.amibay.com/showthread.php...B-Fast-Ram-mod http://leblogdecosmos.blogspot.co.uk...d-64-mo-i.html Last edited by alexh; 04 April 2018 at 14:33. |
04 April 2018, 14:49 | #3 |
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Apologies if I've missed something but none of the linked pages mention the 112MB memory hack, only 64MB? Is this the first time we've seen a 112MB hack for the A4000?
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04 April 2018, 15:04 | #4 |
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Very interesting. How much work is required to 'upgrade' a machine that's already had the 64mb mod done to the new 112mb limit?
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04 April 2018, 15:53 | #5 |
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Sounds like an interesting hack, but I hope Meutoxo does not map the extra RAM into the same address space as 4MB Romy:
http://eab.abime.net/showthread.php?t=88182 $1000000-$13FFFFF Last edited by SpeedGeek; 11 September 2018 at 15:48. |
04 April 2018, 17:35 | #6 | |
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Quote:
Last edited by hooverphonique; 04 April 2018 at 18:51. |
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04 April 2018, 18:47 | #7 | |
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Quote:
Would it be possible to locate ROMY's extra ROM >1MB elsewhere? |
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05 April 2018, 13:53 | #8 | |
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Quote:
Code:
A3000 and earlier systems. Chip RAM, for example, is mapped as in earlier systems at $00000000-$001FFFFF. Since the original Amiga architecture supported only 2MB of Chip RAM, though, any additional Chip memory will have to be mapped non-contiguously. The A3000+ solution to this is to map the memory at $00000000 to the base of a new region, starting at $01000000. The A3000+ architecture physically supports 8MB of Chip RAM, so should an 8MB Alice be designed, the additional 6MB winds up in the $01200000-$017FFFFF range. The next 8MB has been reserved for use as Chip RAM in future systems. Similarly, the A3000 used up all the reserved ROM space in the original Amiga memory map,the range from $00F80000-$00FFFFFF, for the 512K space used by AmigaOS 2.0. To support at least 1MB of ROM on machines with 24 bit addressing, the previously unused 512K from $00E00000-$00EFFFFF. To support additional ROM in an upward compatible fashion, the A3000+ addresses 4MB of ROM at $03C00000-$03FFFFFF. The 512K chunk at $00F80000 is also mapped at $03F80000 and the 512K chunk at $00E00000 is also mapped at $003E0000. |
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05 April 2018, 21:23 | #9 |
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Well I cannot even see use for more than 1MB of rom. so.. 112MB is no issue for me
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06 April 2018, 12:32 | #10 | |
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Quote:
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06 April 2018, 15:06 | #11 |
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Looks like new A4000 motherboards will need some jumpers, hehe.
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06 April 2018, 15:08 | #12 | |
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Quote:
Also, exec does configure any Fast RAM but only Chip RAM! Both the A3000 and A4000 motherboard Fast RAM is configured by the "Bonus" code. The bonus code just checks for Fast RAM below $8000000 and keeps adding it until no more RAM is found. EDIT: If Meutoxo want's to use the space originally reserved for Chip RAM expansion for his hack he has just as much right to use it as I do. I just thought he should be warned about the 4MB Romy version in advance. Last edited by SpeedGeek; 06 April 2018 at 18:11. |
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09 April 2018, 09:01 | #13 |
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06 September 2018, 12:37 | #14 |
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From A4000 Service Addendum - part of A4000 memory map:
16+88+8=112MB - that means romy can't be there or you must use only 108MB (112-4) somehow. A4000 maps motherboard Fast RAM backwards from 07FFFFFF. That mean if you put 1MB of that memory it is from 07F00000 to 07FFFFFF. 2MB goes 07E00000 - 07FFFFFF. ... |
06 September 2018, 16:18 | #15 |
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AFAIK Meutoxo has already released the 96MB Fast RAM version. But of course, the 1MB Romy version solves the problem too.
BTW, I've already had 2 requests for an 8MB Romy! (No good deed goes unpunished). |
13 September 2018, 02:07 | #16 |
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At that rate, let's go back to an A1000-like WCS option with a boot strap ROM (if you don't want the stock-like releases)? That would make it easier to load the (experimental/final) ROM image from the HD instead of floppy, and we don't have to worry about calling for FastROM as it's already in 32-bit RAM.
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10 March 2019, 18:28 | #17 |
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Q01:
Is there any downside of doing this mod? Compatibility issues with software/hardware? or any other known issues? Q10: The PDF says (page 2): -"For 112MB config you should use 2x 64MB simms connected to U852 and U853..." Currently I have the 64MB mod with 2x32MB(double sided) in every second fastram socket U852&U850 (only these two fastram sockets are soldered onto the board in order to be able to use double sided rams properly). Is it possible somehow to use U852&U850 for this 112MB mod with 2x64MB(double sided) instead of U852&U853? Q11: -Still page 2: "... or a single 128MB simm connected to U853 (the 2nd fastram simm)" Isnt U853 the 1st fastram simm on rev B? Or it was meant to be: "...U852(the 2nd fastram simm)"? |
11 March 2019, 10:39 | #18 | |
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05 April 2019, 00:38 | #19 |
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Thanks a lot hooverphonique.
Last edited by discigabi; 06 April 2019 at 18:17. |
10 April 2019, 01:38 | #20 |
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If anyone is interested I have pulled together a brief "guide" of a non-destructive implementation:
http://bit.ly/A4000_112MB_upgrade_supplmtry |
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