+acadiel Posted September 13, 2012 Share Posted September 13, 2012 Figure I would fire this up again, since I've gotten multiple email requests asking for a demo. http://youtu.be/7IL5MKk7UbA The 74LS378 version works well. Thanks to Ksarul for doing the board layout and all the enhancements he has done, and to Tursi for the GROM emulation he's working on! Note that the 74LS378/379 uber-GAL is still giving me trouble; Tursi wrote an awesome bank switch tester to make sure the banks were being banked to correctly. It as well as the 512K Multicart EEPROM work well in the 74LS378 board, but the bank test throws some strange results (different, I might add) with the GAL version - even with two identically programmed GALs. Maybe Tursi or Matthew have some ideas based upon the output shown in the video. At this point, if we can get the GAL working properly, then we have two options for a 512K ROM cart. Once Tursi finishes the GROM emulation remapping (to a new chip pinout), we will then have the capability of making GROM/ROM cartridges, such as XB replacements (like RXB), Plant Genetics and other GROM cartridges can finally take physical form, and more!!! Sorry, Mr. Hull - no RAM in this one 5 Quote Link to comment Share on other sites More sharing options...
+retroclouds Posted September 13, 2012 Share Posted September 13, 2012 Very nice It is really a shame there is no RAM in there though. Would have been so cool if let's say 1/2/4k could be mapped as RAM. The RAM is especially important to get away from the pure assembly language programming. Quote Link to comment Share on other sites More sharing options...
Willsy Posted September 13, 2012 Share Posted September 13, 2012 Yes, very very cool! I would also like to echo Retroclouds sentiment about the ram, too. It *really* needs it. I think the current design is fine if all you want is a super-super-uber cartridge full of old 1980's software... No problem at all with that. However, I'm not really that interested in that - sure, it would be useful to put a bunch of games into one cart, and also have, say, XB and ED/AS on a single cart, really good stuff. However, I'm much more about *new* software, using the cartridge format as the default medium (the ultimate plug and play!). The problem is, 256 bytes of RAM on a stock TI is too much of an 'environmental restriction' (actually, it's more of a 'mental restriction'!). So, yeah, I would like to see 1, 2, or 4K of RAM, too! 2 Quote Link to comment Share on other sites More sharing options...
+acadiel Posted September 13, 2012 Author Share Posted September 13, 2012 The AVR will have 2K of EEPROM space which can be rewritten through the GROM interface. There will also be some volatile GRAM that can be read/written to. However, you can't run 9900 code from GRAM, but you can do other fun stuff. Tursi can elaborate more on what he's doing with the AVR.. I'm just responsible for the ROM section Quote Link to comment Share on other sites More sharing options...
Tursi Posted September 14, 2012 Share Posted September 14, 2012 All the AVR stuff is via the GROM port, and includes access to most parts of the AVR. RAM is included, though of course it's GRAM. You can use it for whatever you like, but on any console with GROMs in it it will be slower than console RAM. It's also not random access. So.. it can be useful for such things as buffers or paging, for example, less useful for things like main-loop game variables. The EEPROM and Flash are too slow to be used as RAM replacements, not to mention each has a limited number of erase cycles. By coincidence I was looking at this just a few days ago. Quote Link to comment Share on other sites More sharing options...
CantStopClicking Posted September 14, 2012 Share Posted September 14, 2012 Wow, this sounds super cool! +1 here! Quote Link to comment Share on other sites More sharing options...
+acadiel Posted September 15, 2012 Author Share Posted September 15, 2012 Hey Matthew - with the GAL version; any idea why I'm getting different bank results on the identically programmed GAL on two carts? I saw the inverse worked ok on the cart.. it's the non inverse that's giving me issues. Quote Link to comment Share on other sites More sharing options...
Tursi Posted September 16, 2012 Share Posted September 16, 2012 In the video, both inverted and non-inverted were giving incorrect results -- although inverted was /close/ to correct. Could be a timing issue? Quote Link to comment Share on other sites More sharing options...
+acadiel Posted September 17, 2012 Author Share Posted September 17, 2012 In the video, both inverted and non-inverted were giving incorrect results -- although inverted was /close/ to correct. Could be a timing issue? And what would explain the inconsistent results between the two cartridges. Your bank switch testing program you authored really helped me out on this!!! Thanks! I'm a fan of the 74LS378, because I haven't had issues with it, but if we can get the GAL working properly and fix whatever the issue is, I'm not against using it either. Matthew - thoughts? Since I know you did build a GAL that did bank emulate the 74LS379 and it did work. Quote Link to comment Share on other sites More sharing options...
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