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Re: [N8VEM-S100:1957] Programming GAL's

On Oct 9, 2013, at 12:19 PM, monahanz <mon...@vitasoft.org> wrote:

> For programming them I would prefer not to use a high level language (the logic is simple, few chips).  I was thinking of using something like PALASM. Could somebody direct me to a DOS/Windows version that I could get a run-time version.  I see many references/write-ups but no actual run-time code. 

PALASM is a great choice.  It gives you very direct control over what's going into your chips; for something the size of a GAL, that's vital (and a higher-level language is generally massive overkill).  Lattice's ISPlever at least used to be a great choice; I think you can still download (for free) a version that'll make GAL bitfiles.  That's what I used last time I had to make a GAL file for a vintage board that needed a replacement PAL.

I think I might have source lying around on my hard drive for an open-source GAL-compatible PALASM workalike that I found online as well, but I wouldn't swear to it.

Worst case, the GAL datasheets detail exactly what bits do what, so you could always handcraft your bitfiles.  That's a LOT of bits, though, and a lot of minterms to figure out if you have complex equations, so it's much nicer to let PALASM do the heavy lifting on that.

As far as programming them, I use my EPROM burner.  There may be other simple homebrew ways (I think I have documentation on the programming algorithm as well, which was devilishly hard to find last I looked), but I don't know them off the top of my head.  If anyone needs a part programmed, I'll be glad to do that if you send me parts (or money to buy them) and a bitfile.

- Dave