ParanoidLittleMan Posted October 5, 2019 Share Posted October 5, 2019 I was thinking after this thread: https://atariage.com/forums/topic/296830-bought-wrong-size-tos-chip/ It is possible to solve TOS 2.06 in ST, Mega ST with existing 28 pin sockets if using EPROMs 27C512 . Will need 4 of them to get needed 256 KB capacity. Chips may go direct in sockets on mainboard, except pins 20 of 2 EPROMs in middle (FD-H and FD-L). Will need special soldering pad setting and simple additional circuit for new address space - 1 GAL chip for instance. EPROMs 27C512 are still available. 2 Quote Link to comment Share on other sites More sharing options...
+DarkLord Posted October 7, 2019 Share Posted October 7, 2019 I would love to get TOS v2.06 into my Mega ST without using a board that interferes with my AdSpeed accelerator. Quote Link to comment Share on other sites More sharing options...
ParanoidLittleMan Posted October 8, 2019 Author Share Posted October 8, 2019 I made it in my Mega ST. Here is how looks: EPROMs go in original sockets, so not higher. I soldered GAL on top of 1 20 pin TTL chip - that's where flat cable from CPU goes. But it can be placed anywhere (near) . Need to solder some 15 lines, most is between CPU and GAL . That's only way without some intermediate board, sockets. I'm ready to ship this - 4 programmed EPROMs (US 2.06 TOS is what I used here) + programmed GAL for decoding new address space of 2.06 for ST, Mega ST. Quote Link to comment Share on other sites More sharing options...
+DarkLord Posted October 10, 2019 Share Posted October 10, 2019 Do you have any idea whether or not it will clash with existing accelerator boards like the AdSpeed? Thanks. Quote Link to comment Share on other sites More sharing options...
ParanoidLittleMan Posted October 10, 2019 Author Share Posted October 10, 2019 According to what I read about AdSpeed it is 16 MHz CPU with some cache, so basically very similar to what is in Mega STE . What means that should work with any TOS version. Couldn't find some photo of installed ST version, so can not say how will be good to connect to CPU lines (mostly address) with GAL for address decoding. In any case, those lines - A17-A23, /AS, /RW, /DTACK are accessible at other locations too. Quote Link to comment Share on other sites More sharing options...
+DarkLord Posted October 12, 2019 Share Posted October 12, 2019 Just to give an example, it won't work with the the MonSTer board - some kind of conflict. Quote Link to comment Share on other sites More sharing options...
ParanoidLittleMan Posted October 13, 2019 Author Share Posted October 13, 2019 15 hours ago, DarkLord said: Just to give an example, it won't work with the the MonSTer board - some kind of conflict. That's pretty bad formulation. Since MonsTer self has TOS 2.06 support, you don't need this solution described here. Quote Link to comment Share on other sites More sharing options...
+DarkLord Posted October 18, 2019 Share Posted October 18, 2019 Umm, that's why I'm *not* using the MonSTer board...and thus, no TOS v2.06, because it conflicts with the AdSpeed. Quote Link to comment Share on other sites More sharing options...
ParanoidLittleMan Posted October 19, 2019 Author Share Posted October 19, 2019 Not sure that it really conflicts. Someone has concrete experience and explanation ? Even IDE port on Monster should work well, because AdSpeed slows down to 8 MHz when accessing regular memory, ROM and bus (and IDE port is on it). Of course, there may be conflict about how to install it physically. Quote Link to comment Share on other sites More sharing options...
+DarkLord Posted October 22, 2019 Share Posted October 22, 2019 I had actually already bought one before I found out about it. In was in a thread on Atari Forum, I believe. Alan H. explained that both devices use the same resources (IRQ line or address maybe?) I don't remember exactly but I could probably look it up. Quote Link to comment Share on other sites More sharing options...
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