KubaCZ Posted January 7, 2012 Share Posted January 7, 2012 I've got recently 16 41256 memory chips so I've wanted to modify one of my XL's to have 320kb ram. I've tried to make it using this tutorial: http://blog.3b2.sk/igi/file.axd?file=2011%2f7%2fATARI800XL320KB.pdf but it doesn't work - just doesn't start, black screen. If i use RAM320XL here with remap option, it boots. So is there some better manual in english? With pictures of schematics would be even better Quote Link to comment Share on other sites More sharing options...
Gunstar Posted January 7, 2012 Share Posted January 7, 2012 (edited) Sorry, I can't help with that particular upgrade. I posting becuase I didn't even know there were 320K upgrades for the XL. I thought that was the realm of the 130XE due to it's extra row of ram chips. I thought the XL's were restricted to 256/512k unless you use SIMMS or a much more extensive than need be uprade (since piggy-backing 256 chips for 512K is easier). Edited January 7, 2012 by Gunstar Quote Link to comment Share on other sites More sharing options...
Rybags Posted January 7, 2012 Share Posted January 7, 2012 From what I can gather, it looks like the 256 is on a daughterboard ? A properly installed RAM upgrade that leaves/uses the normal 64K in place should allow the system to boot normally, even if you don't populate the extra RAM in the board. The extra RAM only maps to $4000-$7FFF via PortB and the stock OS never "goes there" - aside from the Self-Test on later XEs that caters for 128K. Can you try the upgrade without the RAM inserted? If you want to check all the wiring etc. pay attention to address lines and any connections to the PIA. If something's amiss then maybe it's trying to map in the RAM under the wrong circumstances. Quote Link to comment Share on other sites More sharing options...
sloopy Posted January 7, 2012 Share Posted January 7, 2012 I would highly suggest the Hias 512k SRAM upgrade at http://www.horus.com/~hias/atari/#sram512k instead. Its very reliable, includes compatibility with separate antic access, and is rather simple to install. The SRAM is rather cheap (easily gotten for under $10USD (8euro), and can commonly be found for less then $5USD ( 4euro)... And the GALs needed can be had pretty cheap, already programmed... (I usually sell them for $6USD shipped in the US). sloopy. Quote Link to comment Share on other sites More sharing options...
KubaCZ Posted January 7, 2012 Author Share Posted January 7, 2012 Here is how my version looks: 41256's are piggybacked on original RAMs, they have bent and connected pins 1,9,13,15 which go to new 74157. That board is connection of 7432, 7408 and 7404 as shown in schematics. Sice I didn't use sockets on newly added rams I can't test it without new rams. Wiring looks good, but I'm bad at reading german so there's probably something like "connect this and remove that" which I didn't do. Quote Link to comment Share on other sites More sharing options...
Rybags Posted January 7, 2012 Share Posted January 7, 2012 You'd be better off just bodging up a SIMM rather than dealing with that mess. Although a DIY SIMM upgrade will be a mess in it's own right as well, but at least the mess is a bit more organised. Quote Link to comment Share on other sites More sharing options...
KubaCZ Posted January 7, 2012 Author Share Posted January 7, 2012 I would highly suggest the Hias 512k SRAM upgrade at http://www.horus.com...atari/#sram512k instead. Its very reliable, includes compatibility with separate antic access, and is rather simple to install. The SRAM is rather cheap (easily gotten for under $10USD (8euro), and can commonly be found for less then $5USD ( 4euro)... And the GALs needed can be had pretty cheap, already programmed... (I usually sell them for $6USD shipped in the US). sloopy. That doesn't look bad, but I don't like to connect it to ROMs because I already have board with new OSes here. Can it be connected directly to CPU? It seems that it just uses D0-7 and A0-A13. That GAL will be problem, I'll maybe have access to some programmer, but probably don't. Quote Link to comment Share on other sites More sharing options...
Marius Posted January 7, 2012 Share Posted January 7, 2012 You can connect the SRAM in Hiass upgrade also to BASIC. I did that too. And ofcourse you can pick all the Address and Datalines from other places (like CPU, ANTIC, whatever) I would NOT build that 'thing' you showed on the picture in an XL. I can promise you that it won't work... and even when it works, it is as instable as possible. Never trust a TTL based memory expansion in Atari XL. Timing is too critical. Atari XE is different story, thanks to special Xe-MMU (PAL). I built that Hiass upgrade in my 600XL (the computer where my BBS is running from). Never had a better memory upgrade. It is very stable; especially because it is using Ph0 in stead of Ph2 signal for timing. Quote Link to comment Share on other sites More sharing options...
KubaCZ Posted January 8, 2012 Author Share Posted January 8, 2012 Ok, I'll try to make it then. Will be 628512-55 RAM fine? Pinout looks same, but still there may be some difference? Quote Link to comment Share on other sites More sharing options...
sloopy Posted January 8, 2012 Share Posted January 8, 2012 Ok, I'll try to make it then. Will be 628512-55 RAM fine? Pinout looks same, but still there may be some difference? Most 512kx8 SRAM's should work... the only DRAM based ram upgrade i will do is a peterson 320K, otherwise i recommend this one... sloopy. Quote Link to comment Share on other sites More sharing options...
candle Posted January 9, 2012 Share Posted January 9, 2012 there are pseudo-static ram chips compatible pinout wise with standard sram chips of that size - especially hitachi 628512 - they won't work with standard timing scheme Quote Link to comment Share on other sites More sharing options...
KubaCZ Posted January 9, 2012 Author Share Posted January 9, 2012 there are pseudo-static ram chips compatible pinout wise with standard sram chips of that size - especially hitachi 628512 - they won't work with standard timing scheme Hmm, the only 512k SRAM I can find near me is this: http://www.gme.cz/pameti-sram/628512-55-p410-048/ , it looks it's from "Chipus", but datasheet is from Samsung. Hope they're compatiable. Is there any list of tested and working rams? Quote Link to comment Share on other sites More sharing options...
sloopy Posted January 9, 2012 Share Posted January 9, 2012 I usually will order from here... http://www.futurlec.com/ICRAM.shtml sloopy. Quote Link to comment Share on other sites More sharing options...
HiassofT Posted January 9, 2012 Share Posted January 9, 2012 Hmm, the only 512k SRAM I can find near me is this: http://www.gme.cz/pa...12-55-p410-048/ , it looks it's from "Chipus", but datasheet is from Samsung. Hope they're compatiable. This site links to 2 datasheets: one for a Samsung chip and another one for the BSI BS62LV4006. I had several problems with the BSI chip before, but they are all fixed in the latest version (1.3) of my GAL logic. The Samsung SRAMs worked very well in other projects, I haven't tested it yet in combination with my RAM upgrade, but I expect it to work fine, too. so long, Hias Quote Link to comment Share on other sites More sharing options...
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