snweprom cart questions

snweprom cart questions
by Guest on 2005-12-29 (#7822)

I've got a snweprom prototype board for the nes (the same used in the proto version of NES OPEN TOURNAMENT GOLF). It has a place for 2 eproms, battery backed up memory, wram, and 4 spots for lockout chips (kinda looks like a skeprom board).

I belive that they have two spots for eproms are both prg. So I suppose a game uses this type of cartridge because they need a little more control over the pictures than a eprom chr would allow.

Does a game like nes open tournament golf use a bunch of sprites to create he picture in the wram, or does it actually calculate the picture in some sort of psudo 3-d? I haven't played the game, so please don't just tell me that it should be obvious (I'm lookin for it on ebay today!).

Also, does anyone know of any other games that use this type of memory configuration? Thanks!

by sevast on 2005-12-29 (#7823)

that's me in the first post... hmph...

by Memblers on 2005-12-29 (#7825)

I'm almost certain Mario Open Golf uses normal CHR-ROM and is tile-based. It's been a while since I played it though. The only golf game I can think of that generates it's graphics on-the-fly is Jack Nicholas golf by Konami (which looks quite cool, though it makes the game a little slow-paced).

No way there could be 4 spots for lockout chips, heh, having more than one makes no sense to me. It could possibly be address decoding logic to select one of the multiple EPROMs. I think lots of the older EPROM carts would use several smaller EPROMs rather than one large one, since I'm guessing the 256kB and 512kB EPROMs must've been less available or more expensive back then.

by sevast on 2005-12-29 (#7840)

I'm sorry if I wasn't clear. The board snweprom is a prototype board. Please go to this link at nesworld to see a picture of the board:

http://www.nesworld.com/pr-notg.xml

Click on "available" next to PROTOTYPE PCB SCAN to see a picture of a snweprom board.

I have one of these boards, but it is a blank board (nothing soldered on it at all). I want to turn it into a development board, but am looking for more information on the type of game I can use it for and why nes open tournament golf might use this setup.

Are there other games that use this type of setup?

by Quietust on 2005-12-29 (#7844)

Where on earth did you manage to get a blank prototype cart board?

by Memblers on 2005-12-29 (#7850)

What the.. yeah those are extra spots for lockout chips. Still doesn't make sense to me, but you're right, heheh.

Looks like SNROM (makes sense with it being SNWEPROM), which is MMC1. You could run stuff like Final Fantasy 1 and 2, Ultima Exodus, etc. See the North American cart board list here:
http://www.parodius.com/~veilleux/boardtable.txt
Ah, I guess NES Open Golf is SNROM also.. I was sure earlier that it was MMC3/CHR-ROM, but I must've been remembering wrong.

Quietust: I've been surprised before. I've told my little sob story a bunch of times before, but here it is again, heheh. Must've been 4 or 5 years ago, on ebay someone was selling severals lots of unused TKEPROM boards for practically nothing (was 10 boards in each lot I think). But I tried to get all sneaky and do a last-minute bid, but I overslept or forgot, missed the deadline on all of them. Oh well, wouldn't have been too useful anyways. Actually with all those empty proto boards floating around, I'd be a little suspiscious of some of the prototype games that turn up for sale.

by Guest on 2005-12-29 (#7853)

Thanks for helping me learn more! Yes, there are 4 lockout chip spots, but only one is used. You have to chose one of the 4 by closing a circuit. I can see that obviously now, but I learned that from kevtris's skeprom site.

http://tripoint.org/kevtris/mappers/mmc ... EPROM.html

I looked up a topic on sxrom series and learned a lot from there.

http://nesdev.com/bbs/viewtopic.php?p=9 ... 84ef1bea2b

I guess I am still wondering why carts want the wram rather than the chr rom. (or should I call it CHR ram?) Does it just allow it to use a greater variety of mixed up tiles and or backgrounds or are there other reasons?

on the dev carts in general. Yeah, they're kinda hard to find, but not normally as expensive as as a prototype. I'm slowly planning a nes game, and it's kinda fun to know I'll be using a real dev cart. I've also got a tkeprom with all the fixings. I'll get some pictures hosted somewhere if ya'll want.

by sevast on 2005-12-29 (#7854)

I guess it's obvious, but that was me again. I guess I'm going to check the log me on automatically box and see if that helps!

by Memblers on 2005-12-30 (#7859)

Quote:
I guess I am still wondering why carts want the wram rather than the chr rom. (or should I call it CHR ram?) Does it just allow it to use a greater variety of mixed up tiles and or backgrounds or are there other reasons?

WRAM usually refers to the cart's RAM that's hooked up to the CPU (SNROM has that also, battery and all). CHR-RAM is on the PPU.

Yep, it allows more variety in the tiles since the program can rewrite a single tile or even single bytes. It's 8kB though, with the other approach (using a larger CHR-ROM) you can bankswitch several times during a frame to show more tiles, or just switch the whole tileset instantly.

With CHR-RAM, you can store the graphics in a compressed format (in the PRG-ROM), even simple RLE compression works nice for that. And another way to look at it, when you build the cart, that'd be one less chip that needs to be programmed.

by sevast on 2005-12-30 (#7862)

Thanks! I apreciate a more detailed answer. I'm still trying to decide which cart style/mapper I want to program a game for first. I have a long way to go, but it's fun to dream further than I am!

by tepples on 2005-12-30 (#7864)

First try NROM because it's so simple.

by sevast on 2005-12-30 (#7865)

I've got a unrom dev cart on the way to me (don't know what the proto board will be called), so does that sound like a good way to start as I build myself up to more complex things? (excuse me for turning this to a newbie post. I planned on asking more questions like this in the newbie section so feel free to move this).

yes, I agree about the fake proto thing. Unless it's cheap enought that I really want the dev cart or I know the person well, I won't buy protos with no known differences.