M72 Reproduction ROM Board w/Integrated Multi - RTYPE SUPPORTED, OLED, SoftDIPS
- Thread starter dewmansnk
- Start date
Yes, that is correct. In order to get a low enough profile to fit without longer spacers, the ROM sub boards have the EEPROMS directly soldered to them. So that presents a little challenge with how to program the EEPROMs. Right now I am pre-programming before I solder them, which isn't necessarily how I want to go live with this project. I have the ROM sub boards setup so that you could program each EEPROM individually if you had an adapter board. My thought is I would make a few of the adapter boards and send them along with the ROM sub board, once you program your ROM sub board, you pass the adapter along to the next person. Also, we could arm a few people with adapters and have a similar concept to the CPS3 SIMM writing service. There is the rare possibility that an EEPROM might slip out that wasn't blank.
Added to the interest list.
This ROM board has the same selector pin header that the original multi, so it should be compatible with the current offerings. I admit I am not really up to speed on the current fan favorite for selector options. I have seen the classic dial selectors and fancy OLED ones too. I tired to help the situation by at least providing the DIP table on the PCB silkscreen.
Added to the interest list.
J
jassin000
Please continue this practice (at least for my order) I lack a programmer and would have to arrange something with another member.
I don't mind paying a "flashing" fee if that is whats required (it would be well worth it on my end, save on shipping twice + payment to another person/party).
having looked at this recently. damn near every M92 game used a different "ROM board", and since the "ROM board" isn't JUST for ROMs but has some customs on it for processing sound and other stuff, the difficulty of a universal M92 Multi is on the order and cost of CPS1.
So the internal debate from the project guys was probably "do we make a $300 multi that ONLY works with Major Title 2, or do we make a complete repo ROM board and reverse engineer the customs at a cost of $800 just so we can support every donor?
J
jassin000
You tell people it only works with Major Title 2 and stop keeping secrets as to why.
If someone else wants to come along and adapt it for others (like the fine work done here to support R-Type) awesome.
At least the project moves forward, its been so long I've totally lost the ambition to do anything with it and sold off all my M92 PCBs (two of which were in fact Major Title 2's because for many years it was the best/cheapest way to get a R-Type Leo I'm sorry if others didn't get the memo and ruined it for everyone that did "support my Gunforce" people are you happy now).
Last edited by a moderator:
there really weren't secrets about this. if you go back and read the thread they explained the difficult many times. it's just people begging for it to support other games created scope-creep to the point of the project being seemingly untenable. The lack of a definitive "this will/wont support Gunforce" was simply a function of the fact that they were working on it but didn't want to get people's hopes up if it didn't pan out.
J
jassin000
You mean like people who already owned two Major Title 2 PCBs and just needed a bank switching board?
Its dead now, and this is why we can't have nice things (too many cry baby noobz "support my never suitable in the first place" PCB).
XtraSmiley
Legendary
Look this thread is about the new M72 board, AKA now even RTYPE will be expensive board, so let's keep it on track.
That being said, M92 multi, $300 with just MT2 or $800 with every M92 PCB, I'm in for freaking one!!!!!!
That being said, M92 multi, $300 with just MT2 or $800 with every M92 PCB, I'm in for freaking one!!!!!!
J
jassin000
Hehe, I haven't been keeping up with prices... In the past R-Type was one of (if not) the most expensive on the platform.
I've seen them sell for close to 1k in the past, not sure if that's only for the special "caged" Nintendo license version?
Assuming everything proceeds according to plan, it will be the most expensive PCB I've ever converted/multi'd.
Last edited by a moderator:
XtraSmiley
Legendary
The last few sold for only $350 and $425 a few months ago... are you thinking of the Leo maybe?Hehe, I haven't been keeping up with prices... In the past R-Type was one of (if not) the most expensive on the platform.
I've seen them sell for close to 1k in the past, not sure if that's only for the special "caged" Nintendo license version?
Assuming everything proceeds according to plan, it will be the most expensive PCB I've ever converted/multi'd.
J
jassin000
Huh I guess this would be a rare case of the price dropping over time?
Maybe the 800$+ auctions were always on the high side, tho I see one just sold on eBay for 600$+20$ shipping.
I've never seen a legit Leo (everyone always converts MT2).
XtraSmiley
Legendary
Well, I guess the price drop was shorted lived, thanks to someone here!!!!Huh I guess this would be a rare case of the price dropping over time?
Maybe the 800$+ auctions were always on the high side, tho I see one just sold on eBay for 600$+20$ shipping.
I've never seen a legit Leo (everyone always converts MT2).
https://www.arcade-projects.com/threads/multi-irem-m92.4562/page-34#post-302315
I replied to your question in the M92 thread 2 months ago
https://www.arcade-projects.com/threads/multi-irem-m92.4562/page-24#post-220385
I even gave Apocalypse a set of the properly decrypted roms and told him to have at it if he wanted
AlxUnderBase
Enlightened
Amazing work here 
Based on feedback and popularity of past threads - the game selection mechanism is a big feature that saw several iterations from dial selectors and growing to more advanced OLED selectors. Continuing the tradition, I would like to make an OLED selector as an integrated part of this ROM board, here are the implementations details so far:
Make a small add on PCB that contains the OLED screen, Arduino and connector for remote board.
The small add on PCB will fit between the leftmost GAL and leftmost EEPROM.
It will connect to the existing PIN header and be attached to the main ROM board with 4 nylon screws.
The remote board will contain an OLED screen, buttons to select the game, reset button to reset the M72.
(As far as I can tell, there was a 'Reset' on the S18 selector, not sure how/if that was ever implemented on the M72 - maybe someone can provide insight to how the M72 is reset with current game selectors)
For connection to the remote board, a 6-wire cable is needed. In the past I have seen USB-C cables and Ethernet - but these all seem far to stiff for a tiny little remote board. For my implementation I am leaning towards RJ12 connectors / cables.
https://www.amazon.com/Pack-Feet-Cable-Modular-Black/dp/B01M0G7VP4
It is 6 conductors, the cables are still cheap and readily available. Most of all its very lightweight phone cord so you can get it in lots of lengths and colors. Plus will be somewhat silly to see a phone jack on the M72 ROM board.
Now the most annoying part - DIP settings. The M72 games have different interpretations of what the DIP switches mean. Some games share settings, but there is little consistency.
https://www.arcade-projects.com/forums/index.php?attachment/22177-m72-multi-all-dips-pdf/
Looking over the R-type schematic I never noticed before but the DIPs are just a 16-bit Word that is selected (by the PLD M72-A-4D) when the address is
"!DSW = !IORD & !A7 & !A6 & !A3 & A2 & !A1;"
http://wiki.pldarchive.co.uk/index.php?title=M72-A-4D
Confirmed by the MAME driver
https://github.com/mamedev/mame/blob/master/src/mame/drivers/m72.cpp
When only address line A2 (0x04) is asserted along with the active-low (/IORD) read signal, then the DIP word is placed on the data bus. Well, on the ROM board, I have access to the data bus, those same address line and the /IORD signal. What if I put in a 16-bit shift register on the same data bus and used the same address decoding for the output-enable on that shift register? What if the input to that shift register was connected to the Arduino that was doing the game selection. Lastly, so there is no DIP fighting, what if I changed that PLD code in "M72-A-4D" so that it never asserted the 'DSW' port - and the DIPs on the mainboard were never able to be addressed?
Well, we get software defined DIP settings, softdips. So now along with an OLED screen to select the games, you can visually edit/save the DIP settings on the games and have those DIP settings be loaded along with the game.
Unfortunately, this means another spin of main boards, now 2 additional PCBs (albeit simple designs) and more delay. I have almost finished the new M72 ROM board layout that includes all the necessary hardware additions (3 new chips, lots of routing) for soft-Dips. I will start working on the little Arduino daughter board that will carry the OLED screen, and lastly the remote board which will just be a screen, buttons and the little RJ12 connector.
Make a small add on PCB that contains the OLED screen, Arduino and connector for remote board.
The small add on PCB will fit between the leftmost GAL and leftmost EEPROM.
It will connect to the existing PIN header and be attached to the main ROM board with 4 nylon screws.
The remote board will contain an OLED screen, buttons to select the game, reset button to reset the M72.
(As far as I can tell, there was a 'Reset' on the S18 selector, not sure how/if that was ever implemented on the M72 - maybe someone can provide insight to how the M72 is reset with current game selectors)
For connection to the remote board, a 6-wire cable is needed. In the past I have seen USB-C cables and Ethernet - but these all seem far to stiff for a tiny little remote board. For my implementation I am leaning towards RJ12 connectors / cables.
https://www.amazon.com/Pack-Feet-Cable-Modular-Black/dp/B01M0G7VP4
It is 6 conductors, the cables are still cheap and readily available. Most of all its very lightweight phone cord so you can get it in lots of lengths and colors. Plus will be somewhat silly to see a phone jack on the M72 ROM board.
Now the most annoying part - DIP settings. The M72 games have different interpretations of what the DIP switches mean. Some games share settings, but there is little consistency.
https://www.arcade-projects.com/forums/index.php?attachment/22177-m72-multi-all-dips-pdf/
Looking over the R-type schematic I never noticed before but the DIPs are just a 16-bit Word that is selected (by the PLD M72-A-4D) when the address is
"!DSW = !IORD & !A7 & !A6 & !A3 & A2 & !A1;"
http://wiki.pldarchive.co.uk/index.php?title=M72-A-4D
Confirmed by the MAME driver
map(0x04, 0x05).portr("DSW"); |
When only address line A2 (0x04) is asserted along with the active-low (/IORD) read signal, then the DIP word is placed on the data bus. Well, on the ROM board, I have access to the data bus, those same address line and the /IORD signal. What if I put in a 16-bit shift register on the same data bus and used the same address decoding for the output-enable on that shift register? What if the input to that shift register was connected to the Arduino that was doing the game selection. Lastly, so there is no DIP fighting, what if I changed that PLD code in "M72-A-4D" so that it never asserted the 'DSW' port - and the DIPs on the mainboard were never able to be addressed?
Well, we get software defined DIP settings, softdips. So now along with an OLED screen to select the games, you can visually edit/save the DIP settings on the games and have those DIP settings be loaded along with the game.
Unfortunately, this means another spin of main boards, now 2 additional PCBs (albeit simple designs) and more delay. I have almost finished the new M72 ROM board layout that includes all the necessary hardware additions (3 new chips, lots of routing) for soft-Dips. I will start working on the little Arduino daughter board that will carry the OLED screen, and lastly the remote board which will just be a screen, buttons and the little RJ12 connector.
Last edited:
I would suggest that the original DIP switches should be fully functional without any OLED selector.
One of the key points (piracy wise) is that all these multis are sold blank so selling a pre-programmed ROM board is not ideal.
One of the key points (piracy wise) is that all these multis are sold blank so selling a pre-programmed ROM board is not ideal.
Yes, the option to use SoftDIPs will be a solder jumper on the ROM board. You can use the OLED display with/without sofdips and Non-OLED display users will still able able to use the existing physical DIPs.
The change to add softDIP functionality would not affect the ability to deliver the ROM board without programmed EEPROMs. The low-profile SUB boards have EEPROMs directly soldered and the chip-select pins are not tied together, so programming after soldering is possible with a pin adapter. The main ROM board has all the EEPROMs socketed so programming and inserting ROMs will still be possible.
I will eventually get around to writing the Arduino code, and hopefully get some cool community created game select screens to include. The Arduino code will have the mapping of DIP switch bit position to friendly names, but nothing that would be considered IP.
bagheera369
Champion
Brilliant work sir.....I just wish I hadn't sold my Rtype.
I've been waiting with bated breath for someone to convert the M72 stuff over to M84 for a multi where the donor boards are affordable....but alas, that seems to be a pipe dream.
I've been waiting with bated breath for someone to convert the M72 stuff over to M84 for a multi where the donor boards are affordable....but alas, that seems to be a pipe dream.
