Dragon's Lair Fans - Arcade Lifestyle
General Chat => Technical Area => Topic started by: Elgen on March 23, 2014, 03:18:59 AM
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http://elgensrepairs.blogspot.dk/2014/03/using-gals-to-replace-small-sparse.html
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Nice read (as usual) :spaceace:
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I just saw it on your blog, very intyeresting :spaceace:
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So basically you make a truth table by "trying" all the possible input combinations and see what's on the outputs and store that, right ?
Very cool solution ! :)
I remember when GALs first got introduced, the stories were that soon the factory made TTL series would be gone and you would "order your TTL chip at the counter and they would make it for you on the spot".......it never happened :)
Do I understand you wrote your own software for your Eprom programmer ? Would love to have a Windows (OSX preferred, but I must stay realistic ;)) program that could support the Needham EM-10. But I guess it's more a hardware issue....it uses the parallel port and most more modern hardware simply is too fast or doesn't support the native mode good enough.
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So basically you make a truth table by "trying" all the possible input combinations and see what's on the outputs and store that, right ?
Hmmm, no that's actually more like the way you dump protected GALs/PALs.
What I do, is just consider the PROM dump as one big truth tabel, with the address lines as inputs.
Then I look at the data one column at the time and every time I meet a 1, I look at the address bits and spit out the corresponding product-term; there's actually not anymore to it. I don't do any fancy stuff like reduction or anything.
Very cool solution ! :)
Thnx! ...and thnx you other guys, as well };-P
Do I understand you wrote your own software for your Eprom programmer?
Yup, but I only implemented the stuff that TopWin6 (the stock software for Top2005+) lacks IMO.
Would love to have a Windows (OSX preferred, but I must stay realistic ;)) program that could support the Needham EM-10. But I guess it's more a hardware issue....it uses the parallel port and most more modern hardware simply is too fast or doesn't support the native mode good enough.
Yeah, that sux. I don't think it's possible. But if the programmer doesn't use very precise timing through the parallelport, you might be able to use one of them USB-thinggies. I know the Fluke9010a is able to use them http://elgensrepairs.blogspot.dk/2012/12/retrofitting-usb-port-on-fluke9010a.html ... have you ever tried one of those?
EDIT: Argh shoot! I now see, that the Fluke uses the serial port and not parallel, sorry...
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http://elgensrepairs.blogspot.dk/2014/03/using-gals-to-replace-small-sparse.html
Nice to see that investing in education pays of for some ;D D66 was right afterall..... Well done, interesting read.
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I'm afraid I don't know what D66 is?!
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I'm afraid I don't know what D66 is?!
:D it's the Dutch left liberal party which has eduction as their main topic for the last local elections and they won big time.
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Ah okay; being Danish, I'm not that strong in regards to Dutch local politics };-P
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Ah okay; being Danish, I'm not that strong in regards to Dutch local politics };-P
better keep it that way :D