GAL 16v8 - wincupl TABLE compile error

Dec 05, 2005 2 Replies
L

Hi



With a GAL 16v8 I would like to programm some kind of decoder (8 inputs, 7 outputs) with the following code:


TABLE input => output { 'b'00000000 => 'b'1010000; . . . 'b'111111111=>'b'1010000; }



the 7 output values are defined in [40 .. 80] and the inputs in [0 ..



255]


When compiling with wincupl I get the following error:



-excessive number of product tems: a1, a2, a3



a0-a6: are the outputs coded to pins 12-18 respective



Is there some type of limitation that using TABLE does not aloud 255 values to be coded? Any hint how to solve the problem?



Best Regards



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A

Yes. A 16V8 is not 256x8 ROM. It can only recognise a limited number of input pattterns (7 or 8 per output). You should study the datasheet.

What do your inputs and outputs signify? Can you post the full table? You might be able to use the spare macrocell as an intermediate result, to make the design fit.

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P

"Lathe_Biosas" schreef in bericht news: snipped-for-privacy@g44g2000cwa.googlegroups.com...

Yes, a GAL16V8 has eight product terms/ouputpin and apparently your table requires much more.

Yes, an oldfashioned EPROM will fullfill your needs unless you require a real high speed. I'm not up to date but I remember 50ns EPROMS. Made by AMD if memory serves. Lower speeds were widely available at the time. Still have a box of pulled 2764 in various tastes, brands and speeds.

petrus bitbyter

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