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Rom burning
Kaneda - Jun 9, 2004
  Kaneda Jun 9, 2004
If i want to burn a game on a cartrige...what model of rom (eprom/eeprom/flash...) i need ? I think about replace existing rom of a low cost Genny game (Fifa, etc..)

I ask because i need to buy a Eprom Burner to repair my arcade PCBs and I would like to choose a model useful for my little genny too!

Kaneda

 Arakon Jun 9, 2004
first of all, you usually can't simply burn a rom and pop it in, the pinout is different for the most part, except for some that require 42 pin eproms, which are hard to find and way expensive. second, you'll have a very hard time finding 16-24 mbit eproms.

the easiest way is to take apart a bootleg cart, cause those usually use normal eproms, but you'll have to split up the romfile to work, usually into odd and even bytes.

 Kaneda Jun 9, 2004

  
	
	

		
		

			Originally posted by Arakon@Jun 9, 2004 @ 12:30 PM



first of all, you usually can't simply burn a rom and pop it in, the pinout is different for the most part,


well..for SIMPLE game, you just need 2 eproms and connect Genny A1-> Rom A0, etc.. no ?

I say that looking at DevSter's work...


  
	
	

		
		

			 except for some that require 42 pin eproms, which are hard to find and way expensive. second, you'll have a very hard time finding 16-24 mbit eproms.


it's my question...

i don't know how to "choose" a eprom...

If i find a eprom seller, what i must know ?

i talk about voltage, speed, power, ....

if i know that, i can then list the compatible eproms and so choose my programmer


  
	
	

		
		

			the easiest way is to take apart a bootleg cart, cause those usually use normal eproms, but you'll have to split up the romfile to work, usually into odd and even bytes.


yes : i almost finish my rom splitter....

Kaneda

 Kaneda Jun 9, 2004
It seems i find a usefull info...

now i need to know what is the minimal specification needed about power and speed (70ns?)

+ tell me if i'm wrong but i can also use full 16bits roms ? like a 256k x 16 no ?

and so, no problem with odd/even

oh my....my electronic learning is soooooooooooo far!

 Arakon Jun 9, 2004
16 bit eproms will let you put a full game on it (i.e. MUSHA works fine on a 4 mbit 16 bit eprom).

small games will work fine like that, it gets problematic (kinda) when it comes to games over 8 mbit.

as for the speed, just about any will do, I've used up to 200 ns slow eproms just fine.

for the voltages, that's a standard.. they run on 5V.

FYI:

http://arakon.dyndns.org/cartsfront.jpg...

http://arakon.dyndns.org/cartsback.jpg...

those are the 2 carts I made a long time ago (they even work for 32X, btw).. unfortunately I no longer have the documentation or tools to split the roms.

obviously, games that need sram won't be able to save on these.. but I also have a wonderboy IV cart that was made from a FIFA cart with sram, which plays and saves great.. it uses a 42 pin 16 mbit eprom, no idea where the guy got it from.. most eprom programmers will only do 32 pin 8 bit eproms, the more expensive ones, or with an adapter, will do 40 pin 16 bit eproms too.

 Kaneda Jun 9, 2004
as my goal is more to make a "real" cart of my demos than burn full game, a 'little' eproms (x8 or x16) will be enought

for the save, i'll see later

so a standard eprom programmer like this...will do...as long as it has 32 pins

Thanks a lot!!!

Kaneda

PS: For people who want to know more, i think you should read this...

PPS: to the mod, i hope all these links don't disturb ?

 Arakon Jun 9, 2004
I recommend looking into the willems programmer, it's a lot cheaper (especially when you choose to put it together yourself) and there's a load of (also cheaper and/or selfbuild) adapters for it too.

 Kaneda Jun 9, 2004
yes...i saw a lot of them on ebay..

but there is so many models!!!

an additional note, why a lot of eproms need a 0.1µF on the VCC ?

how do i know if i need it or no (i read datasheet who talk about and others who don't) ?

 Arakon Jun 9, 2004
that capacitor is just for filtering purposes, and not really necessary in most cases.. the genesis provides a pretty stable voltage.

 Kaneda Jun 10, 2004
Ok...just for safety so...

thanks