What's new

dewmansnk

Professional
Joined
Dec 1, 2017
Messages
233
Reaction score
441
Location
SoCal
M72 Reproduction Rom Board w/ Integrated Multi

I have recreated the M72 ROM board, using SMT components and integrated the Multi that Apocalypse created. This new ROM board is compatible with ALL M72 platforms, meaning that R-type can now be used as a donor for this new ROM board/Multi. I have reached out to @Mitsurugi-w @Apocalypse and have approval and licensing for the use of the Multi on this ROM board.

S167ts5.jpg

  • An original M72 ROM board was captured in KiCad, preserving all the original reference designators and ICs. Net names / pin names were made as consistent as possible with the R-type schematic available. This reproduction ROM board is 95% match with pin numbers and ref designators for the original M72. Pin numbers on the dual-port ram / SRAM were the only changes with the move to SMT.
  • IC packages were changed to SMT, keeping as close to the original as possible. The Dual-Port RAM (MB8421, 8431) is the same as the original M72, just in the SMT package.
  • Apocalypse Muti was integrated into the ROM board, preserving the reference designators as well
  • IC sockets with high temp and high glass content were chosen - this allows the IC sockets to be reflow compatible and allow assembly of the entire board in a reflow oven. (Minus the 2 connectors that interface the ROM board to the M72 stack)
  • A new low-profile lower ROM board was also designed. This should allow for the lower ROM board to be installed without needed the additional spacers. The lower ROM board was split into 2 identical smaller boards, that are now linked with a cable. [My LOHT has much shorter stand-offs between the middle and lower board, so this low-profile board still did not fit without longer standoffs - YMMV]


NE4LwYd.jpg


fKtA0zi.jpg


KyCUOre.jpg


uikWrJf.jpg


  • Don't judge the dupont cable, I only have one of those nice little cables from @Mitsurugi-w

b9V0N5Q.jpg


svEg8kn.jpg


6fbBLjm.jpg


Since this ROM board is using all discrete components, I can actually build this during the component shortage.

I want to use this thread to gauge interest in this ROM board and see if there is any demand.
As for cost, right now I am at about $400 for the ROM board w/low-profile lower boards. I know, I know - its steep.

The component cost on this one is a bit high with the MB8431, MB8421 and the really nice IC sockets driving the cost up. Also, there is the licensing cost for using the Multi - I have worked out an initial licensing strategy where Apocalypse gets a portion of the profits from each Multi sold.


Interested in First Batch of ROM boards:

1. @jassin000
2. @wolfsoft
3. @2huwman
 
Last edited:

ekorz

Multi Boyz 4 Pi
Legendary
Multi Boyz
Joined
Aug 21, 2016
Messages
4,366
Reaction score
5,511
Location
Boston, MA
Wow! I have one of the original m72 or I’d buy one. At $1000/donor pcb I think the m72 had a small buyer base to begin with so I’d bet that apoc’s multi probably ate most of the initial demand.

There are other multi-able platforms out there though, i hope you consider some of them in the future. I can think of several where conversions are possible but no multi is in development (that I know of anyway!)
 

rtw

Champion
Joined
Sep 28, 2015
Messages
1,448
Reaction score
1,573
Location
Norway
Very nice work :D

I can't seem to find any header for using external selectors ?
 

dewmansnk

Professional
Joined
Dec 1, 2017
Messages
233
Reaction score
441
Location
SoCal
Oh yeah, the holes are there but I never had one of those remote selectors so I never populated the pins, its near the left-most GAL, same pinout as OG multi.
 

dewmansnk

Professional
Joined
Dec 1, 2017
Messages
233
Reaction score
441
Location
SoCal
Wow! I have one of the original m72 or I’d buy one. At $1000/donor pcb I think the m72 had a small buyer base to begin with so I’d bet that apoc’s multi probably ate most of the initial demand.

There are other multi-able platforms out there though, i hope you consider some of them in the future. I can think of several where conversions are possible but no multi is in development (that I know of anyway!)

M92 seemed like it was all designed and ready once you can actually buy FPGA's again.
I have an M97 I was starting to look at - not sure of the feasibility of this one - there is an unpopulated connector for maybe additional ROMs, but it just conceptual right now.

Since FPGAs are unobtanium, I have started looking at the Linsen RV901T as a starter board for future Multi work. Has a bunch of level shifted I/O, Spartan 6, Ethy PHY and is well supported by the LiteX project. Plus you can still buy them by them by bucket full for $35 off amazon and $20 from China. Just add in 2x 50-pin headers to your design and off you go.
 

dewmansnk

Professional
Joined
Dec 1, 2017
Messages
233
Reaction score
441
Location
SoCal
Can this be used with any m72 board or just r-type ?
It can be used with any M72 board. You would simply replace the original top ROM board with this ROM board and install the lower ROM board and be all set. It would be more expensive using this ROM board with a non R-type M72 - but the benefit is you would not need to muck with the original ROM board at all. Just remove it and store it somewhere safe.

I have an original R-Type PCB... I NEED THIS PCB ASAP!
Do you have an order form or website where I can purchase?

@kikaso I know I am (happy) :)

I don't have an order form or website. I will edit the first post and start to put together a list of interested people. I am thinking I will give it a week or so and get a list of all those interested in the first batch, then order the boards and parts. Assembly should not take that long once I have the parts in hand, maybe a week or so.
 

dexster

Student
Joined
Jul 30, 2019
Messages
94
Reaction score
57
Location
Australia
Thanks for the reply dewmansnk - I have an immaculate air duel that I could not bring myself to make a multi out of - but this could be doable
 

jassin000

Immortal
Multi Boyz
Joined
Jul 21, 2015
Messages
8,280
Reaction score
7,110
Location
Nashua NH
yea we do hope for brizzo’s m92
I totally gave up on this and sold my last remaining M92 motherboard (at one time I owned three). :(
Users were still (it had been years) asking about supporting Gunforce, and the project guys wouldn't talk about it (confirm or deny).

That rubs me the wrong way, so I'm out.
Not buying that 2x6 multi either. *whispers* Its not a REAL multi anyway, its just a reprogrammable dongle :whistling: ;)
 

Nebula

Professional
Joined
Sep 11, 2017
Messages
240
Reaction score
199
Location
Spain
Amazing work @dewmansnk !

About sub board, EPROMS should be soldered into pcb due to space limitation, right? if not, you need to go to the spacer solution.
 

wolfsoft

Beginner
Joined
Nov 18, 2016
Messages
12
Reaction score
0
Location
Germany
Great i have a R-Type PCB and waiting for years a Multi will come real for this board.
So please add one board for me.
What about a graphical Display for diplaying the current game?
 
Top