This interesting CPS1 bootleg has seven PLDs, five of them are registered so I could dump only the two combinatorial ones.The first is a PALCE20V8H device that was dumped by me and reversed by Porchy in a GAL20V8 targeting device, the other was dumped and reversed by me into a GAL16V8.Both are tested and working.
At the moment I have an X Multiply PCB that shows a “RAM NG 10” error on startup.
Although I have yet to find the problem with this board I thought it best to find out exactly what RAMs these errors are referring to.
To make any sense of this you will need the memory map for the game found in M72.C file of the MAME source code.
Here is a short list of what I have found so far:
0x9c000-0x9ffff = RAM NG 1 (Work RAM)
0xc0000-0xc03ff = RAM NG 10 (Sprite RAM)
0xc8000-0xc8bff = RAM NG 9 (Palette RAM 1)
0xcc000-0xccbff = RAM NG 8 (Palette RAM 2)
0xd0000-0xd3fff = RAM NG (Video RAM 1)
0xd8000-0xdbfff = RAM NG (Video RAM 2)
Its becoming more and more common for power supplies to not supply -5v.
There are devices out there like the “Negatron” that offer a nice and easy way to obtain an adjustable -5v but there is a much cheaper way of getting it providing you can do a little bit of soldering.
Intersil offer a 7660 voltage converter IC. Its an 8 pin DIP device that can be bought for under £1 from Farnell and other places.
Farnell – ICL7660
I bought a couple of these on a recent order to test and the results, as expected, are great.
This is it setup on breadboard.
All that’s required is a +5v input, the ICL7660 IC and 2 x 10uF capacitors to get a -5v output. Add a variable resistor into the mix and you have a fully adjustable device for very cheap.
Here is the diagram lifted straight from the datasheet to show how simple this is.
I dumped 3 PAL chips found in a Gradius 2 board set.
The board set is not fully operational so I have not marked them as tested in case one of these chips is at fault.
I have also dumped the PLS173 chip on this board but it looks very suspicious so I have not included it. If anyone has a dump of this chip or its equations I would be interested in seeing it.
Thanks
Today I’ve dumped all the PALs from an original (by TAD Corporation) Toki PCB.All dumps are tested working in a GAL16V8 target device.There are also other two programmable logic devices on this board (two bipolar PROMS) whose dumps I’m gonna to send to MAME team in order to improve emulation of this funny and addictive game.