|41 halfnut character question|
Message #1 Posted by Eric Smith on 23 Aug 2011, 5:35 a.m.
The LCD drivers in the "Halfnut" versions of the HP-41 series added 32 new characters to the displayable character set, though unfortunately HP did not revise the mainframe ROM code to give access to those characters, so they could only be displayed by custom microcode.
The characters were shown in the CHHU Chronicle Volume 2 Number 4 Page 11.
It is obvious what many of the characters, such as the lower case Roman alphabet, are supposed to be. Some are probably intended to be Greek characters, such as:
110 lower case pi
111 lower case alpha
112 lower case beta
113 lower case gamma
115 lower case sigma (non-word-final)
117 upper case gamma
11e lower case lambda
13c lower case delta
The one that's completely baffling me is code 114 (sixth row, fifth column). Does anyone have a guess as to what that is supposed to represent?
There are suitable Unicode code points for almost all of the 41 characters other than the "hangman" series, although any given font may not include them. For instance, the "alpha append" character (which I usually refer to as "lazy T", is approximated pretty well by Unicode point 22a2, "right tack". Even the left- and right-facing geese are vaguely similar to 2977 (leftwards arrow through less-than) and 2b43 (rightwards arrow through greater-than). Close enough for government work, anyhow.
I'm using DejaVu Sans Mono for a project, and am disappointed that it does not have 2221 "measured angle", which would be suitable for the HP-41 angle character.
I'm not trying to create a font that looks like the HP-41 14-segment display, as Luiz Vieira has already done a great job of that. Rather, I'm trying to put together a monospaced sans-serif font that has representations of the 41's special characters in a style to match a conventional font. I'm struggling through editing a TrueType font with Fontforge, which seems like a good program but I haven't yet mastered it. If anyone here is interested in helping with my little project, please send me email. The fruits of these labors will be demonstrated at the upcoming HHC 2011 conference.