Genesis Flash Carts...need some help

Wakefire · Post by **Wakefire** » Wed Feb 01, 2006 11:28 pm

I was wondering if anyone here is familiar with the technology of how flash carts work. My problem is that I'm not exactly the rich type and I want a flash cart (but the ones for genesis cost 100 bucks). So I really want to make one. If there are any electronics wizards out there, I need to know where to start. Or if possible you could point me in the direction of a more affordable flash cart for the sega genesis.

SgtBowhack · Post by **SgtBowhack** » Thu Feb 02, 2006 6:03 am

I think flash carts on the Genesis are fairly easy to make. Just find a cart that is 32Mbit (just to make sure all pins are connected), desolder the ROM, and solder in a flashable ROM (matching the pins properly). Then find (or make) software to flash to that ROM.

Conceptually, it's very simple, but the need to reflash makes it difficult (you could just make one with an EEPROM socket so that the ROM is removable and you could reflash the ROM itself though) -- that'd be simplest from an overall design standpoint. Genesis carts are very simple - no bank switching (except on Super SF2), and so swapping ROMs is generally all you need (just need to match the address lines, etc. from the Genesis ROM (can be found on the web) to the ROM you put on (datasheet is also no doubt on the web). Presto chango, you have a flashable cart.

(Disclaimer: I am not responsible for illegal use of flash carts... that was done long ago with console copiers.)

Wakefire · Post by **Wakefire** » Thu Feb 02, 2006 9:48 pm

Thanks, I'll look into it. Anyway, about your disclaimer, I don't plan on using roms of games I don't have anyway. I'm just using a flash cart to minimize the amount of used space in a portable genesis that I'm making by not adding a cartrige port.

Wakefire · Post by **Wakefire** » Thu Feb 02, 2006 9:48 pm

thanks.(sorry about this post. my browser sent my last post twice so I changed it

Wakefire · Post by **Wakefire** » Thu Feb 02, 2006 10:52 pm

Give me some examples of 32Mbit carts. Would sonic and knuckles work?

Post by **Skyone** » Thu Feb 02, 2006 11:50 pm

Triple post...

.

http://www.raphnet.net/electronique/gen ... art_en.php

I've made 2, they work awesome.

Wakefire · Post by **Wakefire** » Fri Feb 03, 2006 12:08 am

Aren't there a lot of games bigger than 1024k? For the genesis I mean.

Post by **Skyone** » Fri Feb 03, 2006 12:40 am

Some are, like Sonic and Knuckles + Sonic 3. It's still worth it.

Wakefire · Post by **Wakefire** » Fri Feb 03, 2006 1:36 am

Yeah, I think so too. But those sonic games are like my favorite games for the sega genesis so I am going to try and figure out a way to boost some more memory out of those things. Maybe at the end of this semester I'll know some more about this seeing that I'm taking electronics and all.

SgtBowhack · Post by **SgtBowhack** » Fri Feb 03, 2006 6:04 am

I'm not sure why this guy mentions bank-switching, the Genesis shouldn't need it (it can directly address 32Mbit). Maybe for his 4MBx2 scheme.
http://devster.monkeeh.com/sega/segarom.png shows another dual-ROM configuration, but the one SkyOne gave you is more advanced. Too bad the schematic is less clear.
He does say that his board supports larger ROMs, so it's possible if you can find a DIP version of a larger one. Or you could create a special programmer that programs ROMs in a cartridge...

In any case, this board layout is ridiculously big for what it is. Probably could be dropped immensely (maybe fit into a regular cartridge if you surface-mount stuff on both sides?) I think you should just take a regular Genesis cartridge, desolder the old ROM, and follow generally the instructions given on that site (2 wires per ROM hole, basically).

Also, keep in mind if you're buying EEPROMs or the like, to get ones with speeds that are as good or better than the Genesis cartridge (probably between 90-120ns? I'd have to look). Otherwise the game will be very slow and/or lock up.

Wakefire · Post by **Wakefire** » Fri Feb 03, 2006 11:30 am

That site's forbidden to me. Anyway I'll try to search some more for a larger dual inline package. Again, If anyone's got any more ideas, i'd be glad to hear them.

SgtBowhack · Post by **SgtBowhack** » Fri Feb 03, 2006 7:20 pm

Like I said, you don't need DIP if you make your own programmer. You could solder on a TSOP and program through the cart's connector.

Wakefire · Post by **Wakefire** » Sat Feb 04, 2006 2:54 am

TSOP?(I love one word posts)

SgtBowhack · Post by **SgtBowhack** » Sat Feb 04, 2006 7:01 am

Google?

TSOP (Thin Small Outline Package)
http://www.intel.com/design/flcomp/packdata/296514.htm