|Atmel ARM7 LCD driver: alphanumeric display|
Message #1 Posted by Michele Signorini on 15 May 2009, 5:09 a.m.
As already discussed, using the Atmel ARM7 cpu in the voyager line opens the exciting possibility to resurrect the beloved hp 15c. The largest limitation of the machine would be, as was in 1982, the simple 10 characters numeric display: I would like to discuss [again] about using the 400 pixel display driver of the cpu to control an alphanumeric display.
With a 5x7 dot matrix design, we could get one line of 10 characters with dots/commas (370px) plus 30 annunciators: probably, only 10 characters are not very suitable for complex number handling, equations editing or soft menu implementation.
With a 14 segments design, we could get up to two lines of 12 characters each with dots/commas (384px) plus 16 annunciators: quite good, but the dimensions of the voyager case (without any redesign) fits better a single line display. Furthermore, segmented displays are quite limited in font set.
I propose here an hybrid 5x5 "quasi" dot-matrix design, on which we could fit one line of 14 characters with dots/commas (378px) plus 22 annunciators. This design is probably not original, but I am not able to remeber where I saw it (maybe a VCR, dvd player or car audio display...).
Here you see the configuration of the character matrix, a proposed character set and a picture of an hp 15c (original picture from the Museum, by Dave Hicks) showing an equation.
It has already been discussed about the availability of large dot matrix displays with integrated driver chip (like on the Smartcalc 300s), but consider the dimensions constraints to fit a voyager case.
Comments are welcome!