> David Harris wrote...

>CHALLENGE: can you scan a keyboard, and run an LCD
> display with only 8 pins/bits = 1 port -- without extra active
> hardware?

Yes, with a 4-bit LCD (7 i/o lines needed) and a k/b matrix
of 4 rows as o/p (ie driven) and 4 columns as i/p. Flip between
port as o/p for the LCD and port as mixed i/o for the k/b. If the
4 row drivers are also the LCD data lines, the s/w should be
able to avoid any unwanted writes to the LCD because of
unwanted conditions on RS, R/W and E caused by key presses.
Might take a little work to idiot-proof but I'm sure it could be done

A routine for a scanned 4x4 is at www.piclist.com and has been
discussed on the list some time ago (18 months ?)

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