Re: LZ: Extended mem. format
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list-zshell@lists.ticalc.org wrote:
>
> > Passive. We interface a microwire eeprom (its three wires, clock, data
> > in, and data out. I believe its possible to combine the data in and data
> > out using passive components, but well have to look into that). I Have a
> > 500k-byte EEPROM with a microwire interface, if that isnt enough, they
> > have a 1-meg one you can buy. Basically we wire this to the link port,
> > and do the rest in software.
> >
>
> 500 KBytes!!! Where did you get that???
National. Its microwire though, not i2c
>
> > Active. I like this one better, because you could add a lot more to it.
> > Basically, you take another microprocessor (Probably a Z80, since we
> > already know how to program it) We could hook it up so that if your calc
> > got reset, you could program the thingy to automatically send a backup
> > to the calc if you did an input "cblget",blah or whatever on a cbl calc
> > and go to link receive or whatever. This way there could be variable
> > send/raw send/etc. The only problem is that i doubt if anyone has had
> > any experience working with microprocessors and stuff (Me Included, i
> > got the idea from my Z80 book). Wed at least need a microprocessor, rom
> > code, actually, would probably be eeprom that would be locked by a
> > special switch so that updates could be done without needing a burner.
> > Wed also need either static ram or eeprom, or both maybe. We could leave
> > the scematics open-ended (same with the rom code) so that if someone
> > wanted to use eeprom for no-power storage, and static ram for fast
> > access, although it would be through the link port, so it would be
> > pretty slow. Anyway, i think the practically of this is limited by the
> > fact that it would be to big and bulky.
> >
>
> Actually, I was looking into getting a Z80 chip and doing some
> experimenting with it. I just have to save enought money to buy a
> programmer for the EEPROM first (I found one on the web for $50). I
> have been looking through some Z80 books, and I have a pretty good
> ideoa of how to hook one up (at least I think I do).
Ive been meaning to do that for a while too
>
> > Steve
> >
> > p.s. To anyone that knows the ram+rom of the ti-85, is any of it unused,
> > i wonder how hard it would be to tap the bus (wed only need maybe 16k of
> > address space plus a free port or two for a page switcher. The problem
> > would be fitting all the crap in the case. oh well.
> >
>
> I don't really think it's work tapping into the hardware of the 85.
> It's probably a lot easier and safer to hook up to the link port.
>
> -Ed
Yeah, i know that would be kind useless considering that it would be
easier to build a new calc. hehe
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