> Jimmy Hoffa <[EMAIL PROTECTED]> wrote:
>
> I have something called a "Ramfile" made by a company named "Tecall". It has
> 16 kb batterybackuped RAM, and my question is if its possible to expand ram on
> it? Its very useful, since it allows the usage of files similar to
> autoexec.bas and so. The two memory circuits, are of type 6464.
>
> "JAPAN 8707
> HM6264LP-15
> UO522YYO"
>
I read: 6264 -> 64 Kbit Static RAM (8K x 8 bit = 8 KByte), 28-pin
the "-15" reads as: access time: 150 nanoseconds max.
"LP" probably stands for Low Power, which can be read something like:
specially selected/produced devices with extremely low power
consumption (under certain conditions), usefull for battery-backup
for instance (or laptops, or ....)
I'd gamble the "HM" before it means these parts were produced by
Hitachi, doesn't matter much who produced these anyway.
These can be easily replaced by 'bigger' types: 62256: 32 K x 8 bit
(would give 64 KB. on your thing), 621024: 128K x 8 bit (would give
256 K on your thing). There are bigger ones, and under different type
numbers, but they are available. Mail me if you need pinouts or
something.
> The ROM is of kind "HN27128AG-25".
>
This reads as: 128 Kbit EPROM (16 K x 8 bit, so 16 KByte), access
time 250 nanoseconds max.
Probably contains the software controlling this thing.
> Please help me with this. :)
>
> // Jimmy Hoffa
>
>
> - -- ------ ----- ---- --- -- -- -- --- ---- --- --
> [EMAIL PROTECTED] -- - http://c5.hakker.com/
>
> For PGP key and additional information, finger [EMAIL PROTECTED]
> -- -- --- --- -- -- - -- -- -- - ------------ --- -- - - - -
>
There are about a 1000 ways to put such a thing together, or expand
it, it would see 3 basic steps:
a) Put in larger memory (piece of cake here, altough SRAM's are
relatively expensive, up to a couple of hundred KB's this should be
no problem). Usually these newer/larger memory IC's have a power
consumption comparable, or less, than older parts, PER IC. So a 128
KByte SRAM would use about as much, or less current as a 32 Kbyte
one. No need to make changes to the battery backing these up...
b) Expand the controlling mechanism, so that these can be used
c) Modify the software, so that it uses this new controlling
mechanism & extra memory
I find this an interesting piece of equipment (I made a design for
something like it sometime, just never took te time to build it...),
but please answer these questions:
a) Can you read out this 16 KByte ROM, and maybe put it on the web
somewhere?
b) Is it possible for you to make some kind of a circuit diagram of
the hardware in this cartridge (maybe send me a copy, on paper would
be okay) ?
If you need any extra info about this, like IC pinouts, or MSX
cartrdige-slot connections, please mail me.
Alwin Henseler ([EMAIL PROTECTED])
http://www.twente.nl/~cce/index.htm
http://huizen.dds.nl/~alwinh/msx/supturbo
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