nesdev.org

hey gang sorry if it seems a bit out of the ordinary. I posted in a couple of Different forums and got no response so I'm assuming those forms are dead. What sort of chips do you guys use EEPROM, SRAM, ICS, etc.? I've come into a bulk quantity of new chips and I'm trying to figure out if they are used for what you guys do.

A lot of us use a PowerPak or EverDrive to test daily builds. For making a permanent copy, I think most of us use flash memory, a variant of EEPROM that erases a whole page at a time. These are usually 29F series, or sometimes SST's 39SF series with smaller erase pages for games that save to flash. Paul at InfiniteNESLives.com sells cartridge PCBs (printed circuit boards) that come with flash already soldered on, suitable for use with his USB NES cartridge writer.

A NES or Famicom cartridge consists of one or two (or three, very rarely) Mask ROMs, OTP PROMs, UVEPROMs, EEPROMs, and/or NOR Flash; zero, one, or two RAMs; optionally some discrete logic ICs, an ASIC, a CPLD, or an FPGA; and in the case of the NES, the CIC or a microcontroller-based clone.

Hmm. I have a bunch of 27c512s, 27128s, and literally a few hundred other types. Im looking over a nes tsrom board. I see the number of chips, but what im trying to find is if the chips i got are of any use before i liquidate them.

weaponepsilon wrote:27c512s, 27128s

Anything that starts with 27xxx is (most likely) a UVEPROM.

tsrom board

Nintendo games all used Mask ROMs. Look up your game in NesCartDB for a more precise description of what part is what.

To be honest, the amount of effort to take a bunch of old programmable memory and make a reproduction is large enough that it's basically only worth it for your own purposes ... and then it's hard to use a lot of them.

(Or if you're selling them, but we take poorly to that here.)

So you have a pile of pulled UV EPROMs:

• 27C512, capacity 512 kbit (65536 bytes)
• 27C128, capacity 128 kbit (16384 bytes)

Games using the TSROM board tend to require 1 Mbit (131072 bytes) or larger memories. You can use those for older games and perhaps some homebrew but not any of the larger games, especially not the kind that would go on a TSROM.

weaponepsilon wrote:27c512s, 27128s

These are too small to be useful for most NES stuff. The 27C512 can hold 64KB, and the 27C128 can hold 16KB, and only the earliest NES games have less than 64KB of PRG-ROM and 16KB of CHR-ROM. Almost anything after 1987 or so has at least 128KB.

If you're programming your own stuff though, or using homebrews from other people, then these chips are certainly useful. Most NES programmers nowadays don't make big games. EPROMs are a pain in the ass to erase though, they need to stay several minutes under direct UV light, so you probably don't want to use them during development, only for final carts.

I often (well, I hardly do any hardware work nowadays, since Flash carts are so convenient, but still...) use Flash ROMs. The 29CXXX line to be exact. Flash and EEPROMs are way more convenient than EPROMs, because they can be erased in seconds in the same device you use to program them.

My favorite chips are :
M27C322 --> EPROM --> 2MB --> For making 16 IN 1 Multicartidges
AT27C080 / M27C801 --> EPROM --> 1MB --> For making 8 IN 1 Multicartridges
AM29F040 --> 512KB --> EEPROM --> for making a single mapper 4 or mapper 1 game
KM6264 --> SRAM --> to use as PRG-RAM / CHR-RAM
AX5202P --> MMC3 Clone
KS5361 / AX5904 --> MMC1 Clone
UM6561F --> NES CPU + GPU (NOAC?)
UM6582 --> NES Controller

See thats what i want to know. If my stock is viable and if I even have what youd use. I do have some hm6264-15 ram and a bunch of similar chips. I just sold out of 27128 chips and am slowly going through the rest. Ironically i got a uv light along with a programmer. If i can maybe ill try my hand if i got something to try out on my Nes. Everything else will be liquidated.