aehammond@dahlia.uwaterloo.ca (nq) (03/27/91)
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I am looking for some pointers to information on the HP28S scientific
calculator's hardware. Specifically, I wish to give it serial input
capabilities.
I've seen the reviews on HP28COM, but would like to do this myself.
Has anybody 1) done this
2) know of someone who has/a book which describes it
3) got any opinions on what is a good method
My thoughts on the subject were to maybe bridge on of the keys
and use an assembly program to read it.
How about the IO ports -- is the IR port write-only? (ie IN/OUT instructions)
While I have it open, is it feasible to add a 32K ram chip?
Any and all info, advice etc would be appreciated. (It was hard enough to
figure out how to open the case).
Thanks for reading.
Don.
email DABOWMAN@SYSTEMS.WATSTAR.WATERLOO.EDU ||
DABOWMAN@SYSTEMS.WATSTAR.UWATERLOO.CAroger@hpnmdla.hp.com (Roger Petersen) (04/06/91)
In sci.electronics, nq <aehammond@dahlia.uwaterloo.ca> writes: | I am looking for some pointers to information on the HP28S scientific | calculator's hardware. Specifically, I wish to give it serial input | capabilities. Don, You may want to try posting this to comp.sys.handhelds. There are lots of calculator hackers there (granted, more software focused). Roger