22 Dec
2012
22 Dec
'12
4:20 p.m.
On 12/22/2012 02:47 PM, Tony Duell wrote:
But, if you want to re-code the RO, then either you
have to find a way of
making the ROM i nthe R2D2 chip invisible to the processor (which is not
trivial, given that the address and data is transered serially over the
same line (ISA) and that this singal is needed fro the otehr sections of
R2D2) or you haev to somehow rebuild the functions of the RAM and display
driver. Then you have to interface an EPROM or sinmialr to the Nut bus,
this is essetially the same as making a ROM box or MLDL unit for an HP41.
And finally you have to fit it all in the case.
You know, I still find calculators darned handy, particularly when I'm
working on the system. My HP16C is never far from my mouse, so both are
within reach.
Nowadays, it should be pretty simple for one to take a micropower MCU
such as a TI MSP430 series chip that also has an LCD interface on it and
turn it into just about any specialized calculator that one could
imagine. Select an FRAM variety and you won't even need any power to
keep memory alive.
--Chuck