Re: Galaga 51xx Bin Hit
Tommye Hope
So again it was necessary to do a lot of analysis of the custom IC behaviour in its "natural environment", e.g. the Galaga board. Unfortunately the 54xx is a noise generator. Means, we need to produce the same "garbage" on our replica as we see on the original. Really a challenge to check, I have to say...
The 51xx/52xx and 53xx IC setup was easier to verify, as it has a much more deterministic behavior. I used my FPGA-DIL replacement board and was able to run the replacementson a Galaga, Bosconian and Dig Dug board without problems!
What makes it complicated is the fact, that a fairly complex Microcontroller can be verified only based on the behaviour of a few I/O pins - so the chances to miss some (probably only minor) thing is fairly high.This simply means, that even if it works perfect finally in the above environments, there are still chances to fail in an other environments (like Pole Position or Xevious), just when initialized and used differently. But lets see. I also have a Xevious board but didn't used and check out that one for now. So there is enough to do...
I can provide a basic Xilinx project including the VHDL code which emulates the 51xx, 52xx, 53xx IC sucessfullyon my FDIL setup (xc3s100e-4, see tables on the right) on a Galaga, Bosconian and Dig Dug board (not all boards include all chips, though). The 54xx IC did work as well, but I am actuallyrestructuring the code to separate the proprietary firmware from my code to distribute it without this binaries.For now only the 42pin devices (51/52/53xx) are available as download. Nevertheless, the gate statistics belowis still valid for all setups.
Click here to proceed to the code request page
The synthesis estimates a max. clock speed above 90MHz for the code, although the ICs are expected to run at 1.5MHz.
Also why do parts go End-of-Life when I build something with them ??? I'm having to recode the 51xx replacement as the part used has gone EOL and I have to convert to the replacement.. bleah.. It all takes up time....
The first few boards are made up ! As this is the initial run they're not as fancy as the others.No soldermask or silk screen, but they're fully functional and will be up for sale shortly.
Custom 51xx
For Galaga/Bosco/Dig Dug/Pole Pos etc.It's the big 42pin IC that counts counts, handles control inputs and flashed the start buttons. Upclose and personal pic of the 5100.
Here's one in-place on a Xevious boardset Xevious replacements and Galaga Galaga replacements
Custom 06xx
For Galaga/Bosconian/Dig Dug/Pole Pos/Xevious. This is a 28pin interface chip between the system bus and the I/O bus.Custom IC 06xx Upclose pic.
See the galaga & xevious pics for one in-place on the board.
Tested the ROMs with the EPROM programmer and by substitution. Cleaned the custom chip legs and swapped out the 7xx, 6xx, and 51xx chips. Replaced the ROM sockets and CPU sockets on one of the board sets. The logic probe showed the CPU at 4E was halting. I noticed that when shorting the IRQ pin to D0 (15 to 16) on that CPU the board would run (strangely) and not lock up. Replaced the CPU on each board and played a couple of games.
Removed a 68B09 CPU from socket 4H and installed the proper 51xx custom Namco chip. Replaced the 3 Z80 CPU sockets and the 6 ROM sockets. Board would still either be stuck in a reboot loop or act dead. When it acted dead the CPU was stuck in a reset loop. If the board was slightly flexed it would try to boot.
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