Making PACMAN Arcade PCB Clone Z80, Cad Software for Beginner advice

[Mikek400]

Im looking for a good software package to design PCBs in Linux (or windows if  necessary).

I've set out on a project which I probably won't be able to finish on my own, but would like to try to make some of it happen on my own. The first step being drawing the schematic up in some kind of CAD or PCB software which I will attempt to do.

I am planning on trying to build a PAC MAN / Ms. PAC MAN arcade board clone. I will be using a Z80 CPU like the original board.  The schematic is available freely online but all of the old 1K ram chips (2114, SL 4239, 93415, 27LS00, MB 81205) are obsolete and quite expensive or unobtainable.  This is the part I will definitely need help with.

Maybe its a bit of an ambitious project, but the board isn't insanely complicated so I feel like it should be possible. Although will it be possible without hacking the rom and changing memory addresses due to the use of modern ram?

Anyhow, my first request is advice on a decent software to accomplish this task. I'm running Ubuntu on my computer but have several and can set up a windows pc if required for this.  Any suggestions for software

Second is any advice on the RAM for this project? Can the ram chips in this be replaced with something modern?

Thanks in advance!

Schematic available here, it is in "Pac-Man & Ms. Pac-Man Troubleshooting Part II - Midway" manual
https://www.mikesarcade.com/arcade/manuals.html

Also attached schematic only below without manual.

[james_s]

KiCad will do everything you need, it is completely free, cross platform, this project will be no problem for it. The learning curve is a bit steep and the UI has quirks but that is true of any EDA of any cost.

[Mikek400]

Thanks for the quick reply.
Thats good to hear, I think I even have it already installed on one of my machines.

If anyone has advice on memory that would be great too..

[retiredfeline]

Yes you should be able to use modern parts for the ROM and RAM but you'll have to figure out the memory map. I also noted some parts labelled custom IC. You might need to work out what they do and what to use for them.

There are many boards in that design. It looks like a big project.

[james_s]

You can use modern SRAM chips, it will work no problem. There is already Pacman hardware implemented in FPGA and all of the custom chips have been reverse engineered so they can be implemented with a CPLD or discrete logic. You may also look at Pacman bootleg boards for ideas, I have one somewhere that is much smaller than the original hardware, I recall that it uses some PAL chips for the custom logic.

[Mikek400]

>retiredfeline
Thanks Good to know that can be corrected using memory maps.
Once I get this started and get the schematic all drawn up in KiCad I will have to start asking for suggestions on memory.

Fortunately the custom ICs have schematics on how to build replacements using 74 series logic, if I remember correctly, so hopefully they shouldn't be a problem.

[james_s]

If you are new to PCB design, you might try something simpler as a first PCB to get the hang of the process. That way you are less likely to get frustrated and burn out by taking on something too complex.

[Mikek400]

>james_s

Thanks for the info. I'd imagine all this could be done in a single FPGA.  Pretty cool that someone has done that.  Good thinking about using bootlegs as inspiration and ideas. I will see if I can find any to look at to get ideas.

[Mikek400]

I can see that it will be a challenge. If all parts were still available, I feel like this would be a much easier project.

I can imagine a simpler project first might be good, but I have to find something.

If I could get this accomplished, it would finish my Ms Pacman Arcade cabinet I built from scratch which currently isn't working due to a failed hdd on the emulation pc inside it. 
I do have some motivation to do this because I want to learn more about electronics and design and also want complete my arcade cabinet.

[james_s]

I have Ms Pacman running on several different FPGA boards, and there are a number of other projects out there. I didn't create it from scratch, I started with VHDL released by MikeJ of fpgaarcade.com. If your goal is to build a board based on the original architecture then it sounds like a cool projects. If all you want to do is get an accurate implementation of Ms Pacman on currently available parts then IMO the FPGA is probably the way to go.

[Mikek400]

The FPGA implementation seems pretty cool too.

I'm interested in attempting building this to mimic the original architecture as much as possible. If I can succeed it should be aiot of fun.

[retiredfeline]

Once I get this started and get the schematic all drawn up in KiCad I will have to start asking for suggestions on memory.

Most of the time you just have to figure out where the memory is mapped and what changes to the address line decoders are needed. If dynamic RAM is replaced by static RAM there is also simplification.

[NivagSwerdna]

Arcade boards are large and expensive and often have custom silicon (true of PacMan), although they have standard uP parts e.g. Z80, ROM, RAM etc they spend a lot of their PCB real estate on custom video hardware to get the performance needed... so it is a brave project.

A much easier approach is to go for an FPGA platform and synthesise the hardware... the Mister Project would be a good starting point. https://github.com/MiSTer-devel/Main_MiSTer/wiki

[james_s]

Pacman has very little custom silicon, just a few trivial custom chips which have been reverse engineered years ago. The bootleg board I've got replaces even more of the custom logic with a few PALs, the whole board is about 8"x4". This is a bigger project than something like Pong or Super Breakout but it is not insurmountable.

[Mikek400]

Apparently someone has figured out how to replace all the rom chips with a single EEPROM. 
It is a plug in daughter card for the CPU. Simple enough to use something similar to make this project work.

Even has a single chip ms-pacman looking at the rom files he has posted.

http://www.arcade-cabinets.com/board_hacks/SRPB-PRO-Z80/

https://www.etsy.com/listing/268314156/the-segagremlin-dualvic-plug-and-play?ref=shop_home_active_1 (Not the one for the Z80 i think but from same person and similar design)

[james_s]

There are lots of single ROM hacks like that for old arcade games. Sometimes it isn't possible to truly have a single ROM because you will often have CPU program ROM, and then foreground and background tile/sprite ROMs which are driven by the video circuitry in a separate clock domain. It's certainly possible to put all of the program ROMs in a single physical chip, and usually the video ROMs can be combined into one chip per subsystem.

[S. Petrukhin]

Im looking for a good software package to design PCBs in Linux (or windows if  necessary).

https://easyeda.com/editor

[Jonnyboy]

Hi guys,

I have gone ahead and made a clone of the Midway PAC-MAN main logic board in Kicad.  You can find it in this repository

https://github.com/joncco/midway-pacman

I had a few boards made and populated 1 of them so at least we know it is working. 

As not all the parts are currently still available, I might make some "adapter boards" so we can populate the hard/impossible to find chips with alternatives.  For the first board I populated, I pulled the parts off a dead "donor" board I had lying around.

[bson]

Find a 3.3V CMOS Z80 version, this will make is MUCH easier to design with modern components without having to bridge two power domains (5V and 3.3V).

[mr ed]

Old video games have hw to generate 'sprites', a small block of video hw displaying a tiny image the size of today's windows  icons that can be easily moved around  (via just changing a x,y hw register) without having to do bit mapping. Bit mapping is a tough job on a little z80.
 
I bet you can write from scratch a whole game on modern hw faster than reverse engineering the game.

Also, there is a vintage game ecosystem and simulator you should look into too. Maybe run that on an embedded PC.

[mr ed]

A follow up on the simulator idea, going that route,  you can run dozens of games with exact sound, not just 1 or 2. Most hw games have  inor changes made as each game was created. And you can run vector games like Asteroids, Quix, etc!