30 September 2007, 01:33 | #1 |
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Memory Data Structures
Hello there forum chummies
I am currently redeveloping an A500 Fast Memory Upgrade fo use with an A600 to make this happen, I am changing the 8 1MB Banks of 30pin simm memory for 1 Bank of 72pin memory some tech specs 30pin memory
72pin memory
Well heres my quandary, in restructuring the memory data I am at a well confusion... my initial idea was to use the full data lines from D0 to D31 using CAS#0 and RAS#0 thus allowing my to 4 times as much data for each CAS/RAS level (since i am limmited on physical logica space *and 5v power*) I figured i could use CAS0/RAS0 for the first 4MB and then CAS1/RAS1 for the last 4MB (ie bank 2) for a total of 8MB now the problem I have with that is the initial design (which is known to work) only has 50 DATA lines insted of an expected 64. so i wonder where (a) I have borked it? and (b) am i attempting to use the 72pin simm data structure in the wrong way... I could use some help guys |
30 September 2007, 03:17 | #2 |
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Okay, I now have the full 64 addressing lines that i need (total 8MB ram)
the question is, can i still use the accessing method i described above? |
30 September 2007, 11:56 | #3 |
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Many moons ago, I'm thinking late 386, early 486 era there was some kind of 30pin to 72pin SIMM convertors would one of those things not help you somehow?
http://www.berklix.com/scanjet/pics/ram_adapt.jpg Mind you, looking at it, it seems a purely physical conncetion thingy. |
30 September 2007, 14:24 | #4 |
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@DrF
thats what i was thinking, indeed it just changes the data address / CAS 'n RAS lines!!! whoot thanks buddy!!!! |
30 September 2007, 14:34 | #5 |
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So could you just get 1 of them and plug it in and thats it done?
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30 September 2007, 15:17 | #6 |
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@DrF
yes and no LOL depending on the 72pin PORT I am *assuming* that the 30pin simms require to be all the same size and 1mb or higher (imagining that 4-8MB would be thier limmit anyway) |
30 September 2007, 15:39 | #7 |
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Only 1 true way to know :P
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30 September 2007, 17:38 | #8 |
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I remember those.. the different letters mean that they are a different height and point different ways so you could get four into adjacent 72pin slots. :-)
You must use the same size 30pin simms to populate one of those and naturally all four must be present. |
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