This page is a mirror of Tepples' nesdev forum mirror (URL TBD).
Last updated on Oct-18-2019 Download

Some mapper related questions

Some mapper related questions
by on (#73044)
This was bugging me for some time.
NesDev Wiki states:
1.Camerica
Quote:
In theory, it would be possible to implement the bank select register with a 74HC377 octal D latch, allowing up to 4 megabytes of PRG ROM, but due to mask ROM cost in the NES era, no non-pirate NES cart used this much memory.

So,in theory it's ok to make 4096 kb ROM,and it should work on real hardware? But how then swithch banks,for example?

2.VRC7
In Disch's mapper list he wrote:
Quote:

CHR-RAM note:
--------------------------
Lagrange Point, for some reason I still don't understand, swaps its 8k CHR-RAM around. How this offers any
functionality is beyond me, but the game does it, so your emu must support it.

So,actually.What functionality it offers?I can think about using some sprites as GFX for status bar.

3.MMC5 Goddnes?
NesDev wiki states:
Quote:
1024 bytes of on-chip memory, which can be used for 4 different purposes:
An extra general-use nametable
Attribute and tile index expansion - address 16384 background tiles at once, and allow each individual 8x8 tile to have its own palette setting
Vertical split-screen
Extra RAM for storing program variables

The second option is beyond my imagination.
Does this mean that I can have 16 384 tiles for background at once.
I mean-wiki don't say how it would be possible to address them.
And one more question about MMC5-Wiki says:
Quote:
CHR capacity: Up to 1024 KB ROM (RAM support unknown)

Why it's unknown?Can't somebody write a test program to see if it can load CHR RAM?
I'v seen thread about MMC5 and someone stated that MMC5 ca't use CHR RAM-maybe wiki is just outdated?
BTW:Does MMC5 have battery?

Hopefully you can answer these silly questions. :D
Re: Some mapper related questions
by on (#73045)
Denine wrote:
This was bugging me for some time.
NesDev Wiki states:
1.Camerica
Quote:
In theory, it would be possible to implement the bank select register with a 74HC377 octal D latch, allowing up to 4 megabytes of PRG ROM, but due to mask ROM cost in the NES era, no non-pirate NES cart used this much memory.

So,in theory it's ok to make 4096 kb ROM,and it should work on real hardware? But how then swithch banks,for example?

That's from the UNROM page, not any Camerica/071 page that I could dig up. Do I need to write a new 071 page based on kevtris' description?

Quote:
NesDev wiki states:
Quote:
1024 bytes of on-chip memory, which can be used for 4 different purposes:
[...]
Attribute and tile index expansion - address 16384 background tiles at once, and allow each individual 8x8 tile to have its own palette setting

Does this mean that I can have 16 384 tiles for background at once.

Yes.

Quote:
BTW:Does MMC5 have battery?

Several Koei games on MMC5 have a battery.

by on (#73047)
Quote:
That's from the UNROM page

Yes,sorry about confusion.
Having 16 384 tiles at one sounds insane.
But there's must be some kind of down side.Does game slow down,or something? Maybe scrolling is harder to make?
What about VRC7?
I'm just curious.
It's very handy to have so knowledge guys like you. :wink:
Re: Some mapper related questions
by on (#73051)
Denine wrote:
This was bugging me for some time.
NesDev Wiki states:
1.Camerica
Quote:
In theory, it would be possible to implement the bank select register with a 74HC377 octal D latch, allowing up to 4 megabytes of PRG ROM, but due to mask ROM cost in the NES era, no non-pirate NES cart used this much memory.

So,in theory it's ok to make 4096 kb ROM,and it should work on real hardware? But how then swithch banks,for example?


Just the same way as usual, write the bank number to the register. But instead of having 16 banks, you would have 256 banks.

by on (#73052)
Denine wrote:
Having 16 384 tiles at one sounds insane.
But there's must be some kind of down side.Does game slow down,or something? Maybe scrolling is harder to make?

Not "difficult", just "different". Both the nametable and the ExGrafix attributes have to be updated at the same time, much as on the Game Boy Color. The part of the screen using ExGrafix usually has to be one-screen mirrored, as the ExGrafix attributes (tile bank in D5-D0 and palette in D7-D6) are applied to all nametables. I imagine that one common setup is to run the gameplay area in ExGrafix, with the left 8 pixels hidden, and put the status bar in the other nametable with ExGrafix turned off.

by on (#73053)
Denine wrote:
Having 16 384 tiles at one sounds insane.
But there's must be some kind of down side.Does game slow down,or something? Maybe scrolling is harder to make?


The downside is that you need the MMC5 chip, which isn't cheap. In practice what you do is write to another table of RAM (in the MMC5 chip) that contains the upper bits for your nametable. So yeah that means more work for the code, but it's for an impressive result.

by on (#73056)
Thanks for the info.
Too bad MMC5 can't use CHR RAM :(
Thread can be closed as VRC7 question is not really important.
Thanks! :D

by on (#73057)
Denine wrote:
Having 16 384 tiles at one sounds insane.

I know, right? With that many tiles you can fill 17 screens without repeating a single one! Compare that to the usual 256, which can't even fill a single screen...

Another great thing the MMC5 can do is give you more tiles for sprites... Since the background tiles come from those 16384, all 512 tiles of both pattern tables are available for sprites, if you use the 8x16 mode. Not as impressive as the gains on the background side, but still very useful.

Quote:
But there's must be some kind of down side.Does game slow down,or something? Maybe scrolling is harder to make?

One downside is that since there's only extra memory enough to "upgrade" a single name table, you are kinda forced to use single-screen mirroring. The other is that updating the background will take longer, since each tile is now defined by 16 bits instead of 8 1/2 (since 2 attribute bits control the colors of 4 tiles, the average is 1/2 a bit per tile) in the usual mode.

Like Memblers said, the need for the actual MMC5 chip is the biggest downside. Very few games use it, and nobody so far has been able to make replicas of it, so making carts for MMC5 software will be very hard/expensive.

by on (#73059)
tokumaru wrote:
Like Memblers said, the need for the actual MMC5 chip is the biggest downside. Very few games use it, and nobody so far has been able to make replicas of it, so making carts for MMC5 software will be very hard/expensive.

So we've decapped CIC, CPU, and PPU. The next stop is mappers.

by on (#73089)
tokumaru wrote:
Another great thing the MMC5 can do is give you more tiles for sprites... Since the background tiles come from those 16384, all 512 tiles of both pattern tables are available for sprites, if you use the 8x16 mode. Not as impressive as the gains on the background side, but still very useful.

So I can use 8x16 sprites+16384 tiles for BG?

This interested me.
I mean-CHR ROM can be swapped even in Mid Scanline.
Thanks to that it's really easy to make animated BG.
But if you use ExAttr mode-It's still possible?
To be honest-I don't think it is.
MAYBE it is,but it's hard...

by on (#73116)
Denine wrote:
Thanks to that it's really easy to make animated BG.
But if you use ExAttr mode-It's still possible?

It is kinda possible, because there is a register that lets you to select which 256KB section of the CHR will be used for the background. Since it supports up to 4 of those chunks (for a total of 1MB of CHR), you can have background animations with at most 4 frames, but you might have to mirror a lot of tiles (the ones that don't animate).

by on (#73346)
Hm,I was poking with Disch's mapper list from Romhacking.net.
In mapper no.192 there is something that I don't understand.
Quote:
CHR Pages $08-$0B are CHR-RAM, other pages are CHR-ROM.

I though there's only 0-7 CHR pages.
Theoretically page 8 should be page 0.But when I tried to check it-there was no CHR RAM at all.
So what pages 08-0B means?

by on (#73348)
Mapper 192 is the Chinese counterpart to TQROM (mapper 119).

Quote:
I though there's only 0-7 CHR pages.

The MMC3 supports selecting from up to 256 CHR banks. In the case of mapper 119, banks 64-127 and 192-255 are hidden by a RAM. In the case of mapper 192, this applies only to banks 8-11.
Where do I download Mappers?
by on (#75101)
I`m new here and I want to know Wherw can I download the NROM?

by on (#75102)
I'm not sure that I understand your question. Do you want homebrew NROM games? Or do you want an NROM project template for ca65, ASM6, or NESASM?
Mappers
by on (#75105)
Isn`t the NROM a mapper? if it isn`t the where can I download a mapper for the Repro Pak on www.Retrousb.com?

by on (#75106)
NROM is the retropak the first one. Not MMC1 version, although it could be used since it has more space.

NROM is just the 32K PRG-ROM and 8K CHR-ROM. Since the NES can "see" 32K of program and 8K CHR-ROM without mappers, it needs no mapper so it's technically not mapped. How this is what you were asking.

by on (#75113)
And besides, you don't download mappers for the ReproPak; you buy them from Mouser Electronics and solder them in. For example, most of the supported discrete mappers are based around a 74HC161, possibly with some extra glue logic.

I will split this to HW soon.
Mappers
by on (#75115)
Oh I`m sorry I am not used to NES Development so I was told that I need a mapper for a certain Repropak. So what does a mapper do? and does it come from repropaks? And where do I get a NES Mapper? Because right now I`m utterly confused....
So do I need a mapper? Because I want to know where I can get it...
Re: Mappers
by on (#75116)
TRingo wrote:
So what does a mapper do?

It lets the NES see different parts of the ROM at different times. See Mapper on the wiki.

For NROM, you don't need a mapper; all you need are the case, board, CIC, PRG ROM, and CHR ROM. The "ROMs" in this case are usually UV EPROM or NOR flash memory.
Mappers and ROM CHIPs
by on (#75126)
So if I download the NROM, and that wouldn`t need a Mapper.. So what ROM CHIP do i get?

by on (#75127)
It should say on the site. I think the smallest is the 27C512 or 27C010. Not sure.
finding these Online
by on (#75145)
So Where Do I Buy these Online?

by on (#75151)
http://lmgtfy.com/?q=27C010+eproms


4th one down at futurlec. Also maybe go with EPROMMAN if your getting a few in bulk.


http://www.epromman.com/

Although his chips may need cleaned up.
Buying Parts
by on (#75153)
So wait... is epromman.com where I get everything, because I thought that eproms were ROM Burners..... And I saw that things came in bulk for $25. Thats pretty cheap... but if I buy a bulk item does it come with ROM Chips, Burner, Boards, CIC, PRG-ROMS, etc?
NROM
by on (#75154)
So where do I download the NROM? And is the CH-ROM adownload too? But the thing I`m confused about is that I don`t know what does the NROM do?

by on (#75155)
Heck no, just eproms man. :P


Board: http://www.retrousb.com/product_info.ph ... ucts_id=42


CIC: http://www.retrousb.com/product_info.ph ... ucts_id=37


Blue case: http://www.retrousb.com/product_info.ph ... ucts_id=39


And you have to find a burner. And you don't download NROM. It's a mapper used on mainly early games. The board supports it that I link too without anything but the CIC, Capacitors, and ROM's.
Eproms
by on (#75157)
Wait if eproms aren`t the burners, then what do they do? So I don`t need the NROM if I go to that Board Link? But wouldn`t be more benficial if I got a Repro Pak from www.retrousb.com? Instead of getting a NROM?

by on (#75158)
This guy HAS GOT TO BE trolling us...
Trolling? My bad
by on (#75159)
Oh no I don`t mean to be offensive, I`m just stupid when it comes to programming.... No offense But I`m just being dumb, because I AM NO PROGRAMMER... just an artist... so to anyone I trolled... My bad...

by on (#75160)
Some of the terminology we use might be confusing to newbies. Quick analogy: does "CD-ROM" refer to the disc or the drive? And what does Zippy drive?

NROM is one of the printed circuit boards used in NES games manufactured by Nintendo. You don't "download" NROM.

PRG ROM and CHR ROM are the two ROMs (read only memory chips) soldered onto an NROM board.

EPROM means erasable programmable read-only memory, and "EPROMs" themselves are memory chips. The 27C series EPROMs are UV EPROMs, meaning they can be erased by putting them in an ultraviolet (UV) lightbox for 20 minutes. You need an "EPROM programmer" to put your program onto EPROMs. To put it another way: EPROM is to blank CDs as EPROM programmer is to a CD burner.

ReproPak is a board manufactured by RetroZone. One of its configurations is compatible with games designed for NROM. You'd write the PRG and CHR data to the EPROMs, solder them onto the ReproPak, put it in a cartridge case, and play it on the NES.

Either way, you'll need a programmer (a person) to translate your ideas into the instructions used by the NES's processors. You can prototype your game in The Games Factory or another menu-driven rapid game development environment, and once you have that done, you might be able to find someone here to work with you on your video game project. We could use more artists.

by on (#75163)
TRingo, it looks like you are trolling because you keep insisting on "downloading" NROM after several people have told you it doesn't work like this. So if you are not trolling, you are at least not paying attention to what we're saying to you. If you really want to learn, you'll have to pay attention!

"NROM" is just the name of the board Nintendo used for the first NES games. It had no mapper installed, just the ROM chips containing the program (PRG) and the tiles (CHR), as well as a lockout chip.

by on (#75167)
GZZZZZHHH I WANT A NROM TORRENT RIGHT NOW ^_^ :roll:

-------> []
Programming
by on (#75171)
Dude thanks alot because I'm like well pretty much my head stuck in my butt... Red Forman Quote from That 70's show...