GALs and old PCBs

I've tried three different types of GALs now (all different speeds too) but the results are the same. So presumably that means I don't have a faulty one - or do you mean that the guy who came up with the original JEDEC was maybe using a faulty GAL?

I wouldn't know where to start there I'm afraid - not without a schematic (and no, that's not a hint :-)

Very true - I'll ask around.

Thanks for your help. :-)

To follow-up on this - firstly I haven't made up that 'slowdown' circuit yet, as I've finally managed to contact the guy who came up with the JEDEC and it transpires that he used a 10ns GAL, so I guess my 25ns may be too slow? :)

I've also tried 7ns and 15ns GALs but to no avail.

Perhaps I need to get hold of and try a 10ns GAL?

BTW, is there a JEDEC editor for Windows that a GAL 'dunce' like me could use?

Maybe your board isn't actually the same as his. There might have been some minor change.

Maybe you could send the other guy one of your surplus of programmed GALs and ask him to test it, or even reprogram it for you?

Since you have the working chip, this really would be a good time to build yourself a truth table extractor using a parallel port - perhaps even use one of your extra GALs as an I/O expander. Good project, you'll learn a lot, and likely find a way in which the file you programmed your GAL with does not duplicate the functionality of the original.

That's possible, but I'm not aware of any changes made to this particular PCB (Robby Roto was never a popular arcade game).

Hmmm, yes - good idea.

To be honest I wouldn't know where to start - although some schematics would help. Do any exist on the 'net - a quick search doesn't turn up anything.

I doubt the board is unique to Robby Roto. It's probably used in a whole range of games from that maker. More interesting question is if they made all the Robby Roto's at once, or if a Robby Roto consist of Assy-547, Assy-628, Assy-71 (with rom #521) etc... and could be put together from these more generic stock components at any time over several years. You might also have a replacement for a failed original memory board?

Read up on parallel port interfacing. Start by learning to turn some LED's on and off under software control. Learn to read the state of the status inputs. You may not have enough bits for all the inputs and outputs, in which case you have the option of using a switch for the unused input and manually changing it partway through the run. You can also change the inputs back to the computer - maybe only read half the chip outputs at a time. Or you can program one of your GALs to multiplex the signals, but that's a more involved project.

By the way, this is easier with a windows 98 (or dos) or earlier PC, though there are dirvers such as giveio which will let you program the parallel port in windows XP.

In this case it is as Robby Roto and a few others all shared four of the stacked boards, while there were two other boards in the rack that are unique to each game. In this case it's the Memory Board that I'm having problems with which is unique to Robby Roto. :)

It's definitely an original - matches the schems, serial nos, etc.

Sounds simple. ;)

Thanks - yes, I'm on XP Pro.

Hmm, was wondering if the ram or rom wasn't different speed.

If the other person used 10ns chips and it worked, then 7 or 15ns should be close enough for a 1.8Mhz design. Sounds like logic check is in order. What programmer are you using. Why can't the programmer be used to read the truth table, unless it is something hobby grade as the galblast I found on the net.

Cheers

Checked out the JEDEC and the schematic as far as I can and found no contradictions. The memory map looks like:

0000-3FFF X1-X4 8000-BFFF X5-X8 C000-CFFF X9-X10 E800-FFFF X22-X24 Write E000-FFFF X21-X24 Read

Apparently X21 will not be written, that is to say, not by using this address decoder.

The more I see about it, the more I get the feeling your GAL is not correctly programmed. Do you have any possibillity to read back your GAL by another programmer and check whether the JEDEC is read back correctly? If not, the best you can do is building the hardware I mentioned before. But, drawing a schematic is no big problem. Not to me. But... then it has to be build and hooked up to a PC. I would fire up an old DOS machine and write a quick and dirty GWBASIC or maybe TURBOC program to read the components. That's a lot of work, guess at least a full day. So if you want the schematic, just say it.

BTW to learn about parallel port programming (and many other things) look at

For your application I like to use the EPP-port best.

petrus bitbyter

All the 6116's on the board are HM6116LP-4

close enough for a 1.8Mhz design.

A Galep-4 .....

something hobby grade as the galblast I found on the net.

Read it from the original 82S153 you mean? If so, afraid it can't handle that device. :(

Thanks

Almost - it's C000-DFFF for X9-X10 - a fault in the JEDEC perhaps?

The 6116 at location X21 is battery backed and used to store high scores, game settings, etc.

Afraid not, no. :(

However, it verifies okay with the existing programmer - a Galep-4, details here on that programmer:

Thanks for the kind offer - I don't though want to put you to any unnecessary trouble so let's see how it goes as to alternative solutions.

Many thanks. :)

Cheers

"matt" schreef in bericht news: snipped-for-privacy@news.freeserve.net...

C000-CFFF X9-X10 must be C000-DFFF X9-X10 no JEDEC fault, a petrus typo.

The conitec site seems to have problems at the moment. But FAIK the Galep is a decent programmer. Guess you kept your software up to date. I'm out of ideas for the moment :(

petrus bitbyter

:-)

Hmmm, I can access the site okay.

Yes, the Galep is a decent programmer so I would have thought it would be okay.

Here's a thought - if I was to get the 82S153 dumped, what would be involved in turning it into a JEDEC?

close enough for a 1.8Mhz design.

hmm. the one I have been dreaming about for 2 or 3 years. Over time I guess I transposed verifying devices to reading any device truth table.

Perhaps this is a good time to fire a message to them to provide a program that can be configures for input/output pins and reading truth tables and then I'll purchase it.

purchase it.

Would that be relatively easy to code?

that

I'll purchase it.

With their "UNIVERSAL PIN DRIVER TECHNOLOGY" should be a piece of cake. This could be also used for testing regular logic ICs.

that

I'll purchase it.

With their "UNIVERSAL PIN DRIVER TECHNOLOGY" should be a piece of cake. This could be also used for testing regular logic ICs.

I have read some time ago about one of those new programmable chips ( little more analog than the rest ) and said to myself "this would be perfect for the heart of a programmer". If one of those is the heart of Galep.... I emailed them asking about their plans to provide at least basic program that configures power , input and output pins and sends test pattern and reads the outputs, will see what they say. I have seen other programmers in the past, claming to be able to test TTLs and even RAMs.

Cheers

that

I'll purchase it.

more analog than the rest ) and said to myself "this would be perfect for the heart of a programmer".

configures power , input and output pins and sends test pattern and reads the outputs, will see what they say. I have seen other programmers in the past, claming to be able to test TTLs and even RAMs.

Any reply yet? :)

that

I'll purchase it.

more analog than the rest ) and said to myself "this would be perfect for the heart of a programmer".

configures power , input and output pins and sends test pattern and reads the outputs, will see what they say. I have seen other programmers in the past, claming to be able to test TTLs and even RAMs.

Not a peep and I just realized that it is another product that suffers from devolution.

6 AAA? That does not sound like more power than 2x9V which should be about the same space if not less. I know there are cons to putting batteries in parallel but nothing a WARNING and double pole switch couldn't fix