06 November 2014, 20:51 | #1 |
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Homemade A500 trapdoor expansion?
On Aminet I found this http://aminet.net/package/docs/hard/Tabajara, its to make a A600 trapdoor expansion using a 72 pin simm.
I thought maybe this could also be used, with some adjustments, on a A500. Would/could the following work: connections from trapdoor to a 72 pin SIMM 4Mb XDRD0-XDRD15 to DQ0(DQ16)-DQ15(DQ31) A0-A8 to A0-A8 CASL to CAS0 and CAS2 CASH to CAS1 and CAS3 RAS1 to RAS0 and RAS2 WE to WE +5V to VCC GND to GND and also the EXRAM pin from the A500 connected to GND so the expansion would get recognised. |
07 November 2014, 07:49 | #2 |
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what is your goal with the project?
creating a 0,5MB/1MB slowfast/chip board similar to A501/A501+, or adding the 1,7mb slowfast ranger RAM as well (that will require a Gary hack)? or is it simply for fun using a 72 pin simm instead of DIP DRAM's? |
07 November 2014, 10:11 | #3 |
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Looking at the original project it adds an additional MB of chipram to an A600.
Converting this project to A500, it would only add 1 MB of chipram to an A500+, since that machine is fitted with a 8375 Agnus capable of addressing 2MB's of chip. |
07 November 2014, 15:09 | #4 | |
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Quote:
Once it works as a A501, adding the 1,7mb could be the next step. |
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01 December 2014, 14:50 | #5 |
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Got some time this weekend and made myself a A501 clone with a 4 mb simm and it works great.
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01 December 2014, 21:44 | #6 |
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Sweet Can you post some pics?
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