Re: TI-H: EEPROMS
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Re: TI-H: EEPROMS
This is a very complicated expander you have got in mind!! Analogue
sensors!! RTC!! Although ive not come across the 8535, so it could be
quite easy to do. Being able to implement the expander in a BASIC program
would be pretty good aswell, especially for people like me who dont know ASM
but are have good BASIC programming skills.
Someone could probably quite easily tackle the idea of having an accurate
ref ocillator fed into the clock input of the calc so that you can then have
accurate timings within programs. I understand that all they are using is a
RC setup for the ocillator. How primative! They could at least use a
crystal! Perhaps using a serial RTC IC joined internally to a couple of the
spare IO pins on the processor could be tried. (****TI take note****).
Only a few minor mods and the calc becomes much more useful - like a PDA.
>From this you could then use the extra ports left to trigger things like
alarms etc. Just think - you could control your whole house using a decent
clock reference for the timing, and something to interface to the outside
world through the link port. And as for the software to control it all -
just about anyone could make it.
Im not so sure about the colour display though. I think major surgery on
the calc would be in order to get that up and running!
Although, anything's possible.
Simon.
Forgive the Spelling.
>
>If I were implementing an expander, I would use a largish AVR (8535 most
>likely, because it has lots of room for code and is quite versatile,
>allowing hacker types to do things like attach lots of analog or digital
>sensors without having to add additional microcontrollers to the system.
>It
>includes an onboard RTC (IIRC).
>
>Attach some memory (I'd probably use serial EEPROM) for storage, then, most
>importantly, write the software such that it could operate as if it were
>another calculator on the link port. In this mode you could use the
>expander to initiate a transfer to send custom drivers to the calculator.
>Or you could do something tricky like send a variable to the expander
>containing a number that identifies a piece of data to transmit to the
>calculator. Upon receiving the variable, the expander would then transmit
>back the selected item. A request of a special item would result in the
>transmission of a string containing a listing of all the available items.
>
>This would allow the expander to operate without drivers or a shell of any
>sort. Optionally a second mode could be included to allow more direct
>communication with a driver program (which can allow faster transfers).
>
>Given my predisposition to internal hardware, I would be inclined to design
>it such that it could be mounted internally so I could use one of its IO
>pins to drive the calculators main clock input to allow for features such
>as
>accurate timing on the calculator, software configurable turbo functions
>and
>just MAYBE, a multiplexed color display via the use of R, G and B LED
>backlighting.
>
>Unused port pins and the ISP pins could be brought out of the calculator
>case on a mini-header to allow for external devices and reprogramming of
>the
>AVR.
>
>DK
>
>
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