Re: [stella] RAM Cart?

Subject: Re: [stella] RAM Cart?
From: Mark De Smet <desmet@xxxxxxxxxxxx>
Date: Fri, 15 Jan 1999 18:30:46 -0600 (CST)
> >I havn't had much experiance with the supercharger, but once a game is
> >sent to it, does it work identical to building a EPROM cart?
> Yes, but it isn't persistent.  When you power down, you lose the game.
> Therefore things like "frying" can't be done, for instance.  It would be
> nice if a modern RAMCART used SRAM or EEPROM or something instead of DRAM.

Technology review for those that don't follow.

DRAM or dynamic ram require extra circuits in addition to the memory to
maintain the memory.  I don't know of any RAM carts that use this method
because the extra circuitry is very bothersome to deal with.  I'm not even
sure that it could be used because nothing can be read when it is
refreshing and may cause timing errors.

SRAM or static ram holds all the data as long as the power supply is
connected(many chips can hold data at lower voltages for battery backup)
This is what I, and Pete used.  It is ideal because it is simple to
use(can almost be a drop in for an EPROM cart), and can be battery backed.

EPROM or eraseable programmable read only memory can only be programed
with a eprom programmer.  Once programmed, retains the data for years(can
be erased by exposure to UV light and reprogrammed).(primarily used for
the final copy or for temporaries if the code writer has a EPROM
programmer handy.)

EEPROM or electrically erasable ROM.  Identical to EPROM, but can be
erased in circuit(with out UV light).  I think that it would be really
neat to build a circuit with one of these because you don't need a

Has anyone made a cart out of anything besides SRAM or EPROM?

So the jist is that produceing an SRAM cart isn't really necessary?


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