Atari GPC Chip - It's WORKING !!

[ColinD]

I've been busy..... My Roadblasters 'cocktail' board in the Cockpit has died and needs a new GPC chip.....

I've robbed one from the Gauntlet to repair... so I can test the Slags Modules on it.... alas... not fully working yet on this , but the Slags at least work on Gauntlet....

There are still a couple of problems with the Roadblasters board, H Scroll is not right and no cars... !!

anyway..... thought I'd try to put a GPC chip together in VHDL..... It's took me a couple of days and needed some help with the final high z output on 8 of the outputs..... but it seems to compile ok now....

the design uses a prom for decoding, so I dumped the prom from my system 1 logic board and that's all sweet and included

However..... I need a CPLD / FPGA module with 40 pins..... might see if I can get one from a couple of sources, or I will have to design my own..... !! ( it has odd power pins like the slags)

The only issue I have with this is that in the original circuit there is a /HO3 line.... and this does not go to the GPC chip, so I may have to modify a little or do some testing to regenerate this based around the H4 signal...

ColinD2016-05-21 19:40:38

 

[ColinD]

Need to revisit this... I think I sorted how to regenerate the line that was missing.

I have 2 gauntlet boards and the cocktail roadblasters... and 1 working gpc chip out of the 3 so think these need looking art next !!

 

[Alpha1]

dude you are on fire!!!!

 

[jrr]

Wolf's FDIL-2 is a nice 42 pin FPGA kit might do your job...

http://www.pin4.at/pro_misc.php#fdil

I have some and need to test a GPC right now on my non-working Gauntlet that may need a GPC (I don't have any to test and I am not getting any outputs on my device). If you want me to be a guinea pig send me a note jrr @ flippers com

jrr2016-05-11 19:12:32

 

[FPGAArcade]

Colin,
Drop me a mail (admin @ fpgaarcade dot com)

I've got some of the FDIL S100 modules here. I'm happy to help you with the design - hopefully we can open source it as well.

I've finally got permission from all the authors to release all my Namco28 pins stuff as well.
Cheers,
Mike

p.s. I'll be over in the UK next week (I live in Sweden) so could post you one from there.

 

[ColinD]

Wolf's FDIL-2 is a nice 42 pin FPGA kit might do your job...

http://www.pin4.at/pro_misc.php#fdil

I have some and need to test a GPC right now on my non-working Gauntlet that may need a GPC (I don't have any to test and I am not getting any outputs on my device). If you want me to be a guinea pig send me a note jrr @ flippers com

I can send you the VHDL Files, BUT I cannot guarantee that the design works as is completely untested at the moment on a working board. Plus you would have to convert over to the xilinx software and work out all the connections and configurations, so at the moment, I think there's too many potential things that can go wrong !!

If Mike or Wolfgang want to get involved, I'm happy for them to examine my vhdl code and compare to the schematics I've got.

Regards, Col

 

[jrr]

If Mike or Wolf want to convert the code I would be happy to test it in my Gauntlet (that isn't working and I suspect the GPC - no outputs from it, but have all inputs). You are correct in that I would have trouble recoding your work for the FDIL as coding is not my forte.

 

[ColinD]

I think its best to get the code working first and tested before trying to port.....

 

[ColinD]

Look what arrived today.... They snap off perfectly with the sacrificial through hole pads between the milling slots and the Covers fit perfect over the modules

 

[Hurray Banana]

Nice

 

[philmurr]

Great work again Col

They look superb. Love the idea of the cover.

 

[jrr]

I could really use one!

When available and how much?

Thanks,

John :-#)#

 

[ColinD]

John, let me test the design first..... probably next weekend.... If it at least boots on the gauntlet without any major glitches I'll see if I can get the design over to the module you have to test.... Mike J seems keen to help migrate this stuff so it all helps.

Mike is sending one of his FDil S100 modules, so I may also be able to test it here before you take the plunge..... I need to walk or crawl first before attempting the final sprint though !!

I will also build a couple more SLAPSTIC test modules, so will get one over to you when I'm ready....ColinD2016-05-16 21:51:18

 

[ColinD]

Built the module.....

Went though the code to double check everything and found that my implementation of the 74ls374 wasn't quite right , so fixed that.......

Programmed it up.......

Wouldn't Boot Gauntlet !! - BOOOO !!!! - Black Screen !!!

Forgot I had pulled the Slags chip out, but couldn't find it.....

I should have at least got a ROM error... Thats no good !!! - Double BOO !!!!

Put My SLapstic replacement in......

Still woudn't boot..... Tripple Booo !!!

Head Scratching mode on.......

I went over the design, and spotted I had one of the PFX Output Pins (PFX 3 - Pin 31) going to the wrong pin on the CPLD... It went to Pin 93 which I had grounded on the design instead of Pin 92 which goes to Pin 31 of the IC.....

Changed from Pin 93 to Pin 92, reprogrammed.....

And the Bugger Boots up and runs..... !!!!!

Some of the text appears a bit dark and the SCORES PER COIN is not quite right (pixelated instead of a border) , so I still have to check a few things, but this is LOOKING GOOD.... and nearly worked the first time (would have if I had got the pin right !!).....

Cheers, Col

ColinD2016-05-19 20:17:21

 

[Hurray Banana]

Brilliant mate

 

[ColinD]

Had a good poke about with this, and it seems that the 'missing' /HO3 signal in the circuit but does not go to the chip is not quite right.... I tried to regenerate this signal using a counter, but every bodge or fix makes things worse, so I think/hope I'm along the right track anyway !!

Lets see.... More debugging.... but It's extremely close anyway - Just some Text overlay issues !! Sprites (Motion Objects) and the Playfield Graphics seem to be working perfectly

Cheers, Col

Cheers, Col

 

[ColinD]

I've got it working by changing the timing / power / config settings on the chip .... Seems some of the signals were a bit slow on the alphanumeric circuit.

Picture is now identical on Gauntlet to the Origonal GPC Chip

ColinD2016-05-21 19:43:26

 

[edwoodjnr]

Well done Col, this is very cool

 

[Jodo]

Excellent news!!

 

[VectorGlow]

Jolly good show that man. Well done.