Eprom or Rom /

[pangasinan]

When i open up a cart how can i tell if it uses a rom or and eprom ?? thanks

Edited September 7, 2009 by pangasinan

[Dino]

When i open up a cart how can i tell if it uses a rom or and eprom ?? thanks

 

One way to tell is that the e-proms have a little "window" in the chip. I'm not sure if they all do though.

[pangasinan]

Thats what i thought,i have some games and the chips have round windows on the top of them,but why would they use eproms instead of rom chips for a game thats not a prototype?

Edited September 7, 2009 by pangasinan

[Dino]

Thats what i thought,i have some games and the chips have round windows on the top of them,but why would they use eproms instead of rom chips for a game thats not a prototype?

 

Because burning roms is VERY expensive, so for small runs, eproms made more sense. Some Ktel games, BOMB games, CTCW (i belive), Air Raid, Lochjaw and various other released games used eproms.

[pangasinan]

If its cheaper to burn on eprom,why didnt they use eprom for large runs,are they more expensive than rom chips ?

[roland p]

If its cheaper to burn on eprom,why didnt they use eprom for large runs,are they more expensive than rom chips ?

For large runs, roms are cheaper.

[Nukey Shay]

Quicker to produce, as well.

[robotwo]

They made OTP-EPROMs aswell , they count as EPROMs , but they don't have that little quarts window , since its the most expensive part of the casing to produce.

I was fooled to buy a lot of theese so called OTP-EPROMs in a auction, but it was labeled "27c256 EPROMs"

[roland p]

OTP-EPROMs?

 

That means One Time Programmable-Erasable Programmable Read Only Memory.

So you can program them once, then erase them and then throw them away ?

Edited September 8, 2009 by roland p

[mimo]

OTP-EPROMs?

 

That means One Time Programmable-Erasable Programmable Read Only Memory.

So you can program them once, then erase them and then throw them away ?

 

nope, you can program them once and then throw them away, they are not erasable

[+5-11under]

OTP-EPROMs?

 

That means One Time Programmable-Erasable Programmable Read Only Memory.

So you can program them once, then erase them and then throw them away ?

 

Nice.

[pinball22]

...so for small runs, eproms made more sense... Lochjaw and various other released games used eproms.

 

Are Lochjaws really all eproms? They didn't know when they started that it would be a short run, right?

[+batari]

OTP EPROMs are confusing, but they can't be called PROMs, as PROMs program by blowing fuses and require a different kind of programmer. OTP EPROMs use the same technology as UV-erasable EPROMs and can be burned with a normal EPROM programmer.

 

Maybe you could erase an OTP EPROM if you carefully ground down the packaging and exposed the die to UV light.

[Pitfall Harry]

OTP-EPROMs?

 

That means One Time Programmable-Erasable Programmable Read Only Memory.

So you can program them once, then erase them and then throw them away ?

 

nope, you can program them once and then throw them away, they are not erasable

 

If you take out a big hammer and smash the chip to dust, who says it's not erasable once?

[RevEng]

Maybe you could erase an OTP EPROM if you carefully ground down the packaging and exposed the die to UV light

 

Decapping an OTP EPROM will definitely make it reprogrammable, but if you tried to decap by hand it's fairly likely you'd take out one or more of the bond wires.

 

Intel apparently had some success with using X-rays to erase OTP eproms and annealing them at high temps to fix the damage the X-rays would cause, but that doesn't sound like the most reliable method either.

[robotwo]

I was very surprised when I found out that I had been sold OTP-EPROMS labeled as EPROMS ,

since it kind of made prototyping very hard to do ...

But it was worth it since I payed like 2$ for 18 OTP-EPROMS

 

But I'll definitely have to get some EPROMS aswell ,

since I need to test how well the prototypes work on actual hardware ,

and spending all OTP's on trying different variations of one game seems kinda' like a waste