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Help needed: Rockman 6-in-1 multicart hardware
http://forums.nesdev.com/viewtopic.php?f=28&t=8426
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Author:  80sFREAK [ Tue May 08, 2012 8:38 pm ]
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you can build stand-alone OR gate from 2 diodes and 1 resistor.

Well, back to the topic, schematics complete and pre-checked. Now have to build prototype 8)

Author:  FARID [ Tue May 08, 2012 9:24 pm ]
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Quote:
You don't need it.

Rockman 3, 5 need CHR-ROM, have you found TGROM version of them?

Quote:
Why do you need 16bit data?

If all games are TGROM and uniform, then it will be 6*512KB=3072 for PRG, this much of PRG needs 3*27C080 or 1*27C322

After separating Rockman 4, 6 from Chinese 6 in 1 ROM, they won't work with their original header from Japanese ROM. They must be TGROM but why won't work under that header?! Others work fine.

Author:  MottZilla [ Tue May 08, 2012 9:34 pm ]
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FARID wrote:
Quote:
You don't need it.

Rockman 3, 5 need CHR-ROM, have you found TGROM version of them?


Doesn't exist. There is a reason the games use CHR-ROM and not CHR-RAM. This pirate multi already exists. Why try to re-engineer it? Really just slap enough AND/OR gates together and you can make whatever multi-cart logic you want. And in that case you could just grab a CPLD or maybe a PAL to handle it.

Author:  infiniteneslives [ Tue May 08, 2012 10:00 pm ]
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MottZilla wrote:
This pirate multi already exists. Why try to re-engineer it? Really just slap enough AND/OR gates together and you can make whatever multi-cart logic you want. And in that case you could just grab a CPLD or maybe a PAL to handle it.


AMEN! Apparently isn't not just me.

If you'll accept crap conversions of the original game just buy the multicart or play in an emu.

If you want the original quality buy the readily available original carts. Yes they aren't cheap for all 6 of them but they are great games worth the expense.

If you really want all of them in a single cart to make as some sort of project: Do it right and put all the games on a single cart with their original mapper/board layout mashed into one. Either implement a ton of switches and logic or pick up a CPLD and teach yourself a thing or two. All of these games could be put on one cart with the original mappers. I don't see why it's worth the effort but it sounds like some people might based on the thread.

But don't let me tell you what to do... :)

Author:  80sFREAK [ Tue May 08, 2012 10:51 pm ]
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FARID wrote:
Quote:
You don't need it.

Rockman 3, 5 need CHR-ROM, have you found TGROM version of them?
Again, you don't need it.

FARID wrote:
If all games are TGROM and uniform, then it will be 6*512KB=3072 for PRG, this much of PRG needs 3*27C080 or 1*27C322
Nope. 512kB for CHR and 2MB for PRG. That's all you need.

2 MotZilla hi, boss :)

MotZilla wrote:
Really just slap enough AND/OR gates together and you can make whatever multi-cart logic you want.
Most likely yes, but i had to fall back from your description to the first table. By the way, can you confirm that data exactly correct?

MotZilla wrote:
And in that case you could just grab a CPLD or maybe a PAL to handle it.
Oh, c'mon! Only discrete are true :wink: It's ended with 8 common IC's

2 infiniteneslives I took this mapper as a small challenge. And i will build only mapper, not really interested in Rockman games.

Author:  FARID [ Wed May 09, 2012 1:29 am ]
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I suggest this design, it needs 6 ICs :

Image

Author:  80sFREAK [ Wed May 09, 2012 1:46 am ]
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A bit more than 6(plus you need much bigger EEPROMs), but you gave me good idea, how to return to main menu without powering off console. Thanks for that.

Again, just checked my drawings with "fresh eye". 8 common IC's can do the job. Patching menu can save 1 IC and using different decoder/latches can save another one

Author:  infiniteneslives [ Wed May 09, 2012 2:12 am ]
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FARID wrote:
I suggest this design


No offense, but you're really missing the point about the issue with the '157 not being tristate outputs. Assuming you've got those tied to the NES data bus (and not some separate crazy MMC3 data bus per the label) they will NEVER work. Those chips will ALWAYS drive the data bus lines to a logic 1 or 0. and the CPU MUST be able to drive those lines when it's writing to it's various locations. Your cartridge can ONLY control the data bus when the NES is reading from the ROMs (PRG /CE low and PRG R/W high). You are obviously violating this fundamental rule of bidirectional data buses.

Author:  l_oliveira [ Wed May 09, 2012 5:16 am ]
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infiniteneslives wrote:
FARID wrote:
I suggest this design


No offense, but you're really missing the point about the issue with the '157 not being tristate outputs. Assuming you've got those tied to the NES data bus (and not some separate crazy MMC3 data bus per the label) they will NEVER work. Those chips will ALWAYS drive the data bus lines to a logic 1 or 0. and the CPU MUST be able to drive those lines when it's writing to it's various locations. Your cartridge can ONLY control the data bus when the NES is reading from the ROMs (PRG /CE low and PRG R/W high). You are obviously violating this fundamental rule of bidirectional data buses.


I told him that, even posted about it here ...
He said it works. Fine with me. :)

I know I won't be doing that on my Famicom, though... ;)

Author:  80sFREAK [ Wed May 09, 2012 5:57 am ]
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Well, maybe there is '245 or '541 involved :?

Author:  l_oliveira [ Wed May 09, 2012 5:58 am ]
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80sFREAK wrote:
Well, maybe there is '245 or '541 involved :?


I'm sure there isn't ... I talk to him through MSN and he mentioned he intend to use this configuration. I told him it will not even boot. :)

Author:  80sFREAK [ Wed May 09, 2012 6:33 am ]
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Oh well, let it go. Still wonder, why 16-bit bus?

Author:  l_oliveira [ Wed May 09, 2012 6:44 am ]
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80sFREAK wrote:
Oh well, let it go. Still wonder, why 16-bit bus?


He want to salvage chips.

Author:  80sFREAK [ Wed May 09, 2012 6:51 am ]
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But almost any modern 16-bit flash have Byte/Word config pin :?

Author:  l_oliveira [ Wed May 09, 2012 7:14 am ]
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80sFREAK wrote:
But almost any modern 16-bit flash have Byte/Word config pin :?


It's the case of salvaging whatever you have in hand, I'm quite used to that and a lot of times people ask "why you used this part, that other one would have been so much better ... " yes, but these people don't realize that you can make the exact same digital circuit from a hundred of different ways and all can do the exact same thing. It just depends on which parts are easier to get.

That's what kyuusaku is talking about when he said " '157 would be appropriate since it's more common than OR gates."

Back then Nintendo would be buying new parts so an 74LS32 would cost less than a 74LS157 in bulk quantities hence their design choice.

At this point we're mostly recycling old technology out of passion so the considerations to be made are slightly different. Don't you think so ? :)

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