|HP-ASCII and Trigraphs||Back to Index|
As mentioned elsewhere, HP calculators use a non-standard version of ASCII which does not directly map to the Macintosh's ASCII based disk file system and is difficult to input on a standard keyboard. Fortunately, HP also provides a work around for these limitations: When you send or receive HP objects as text files, HPConnect will translate these special characters into "trigraphs" - groups of three standard ASCII characters. These trigraphs can be readily input with any standard keyboard and even a simple text editor:
|129||\x-||Mean (bar-x)||130||\.V||Inverted Triangle|
|137||\<=||Less or Equal||13||\>=||Greater or Equal|
|141||\->||Right Arrow||142||\<-||Left Arrow|
|143||\|v||Down Arrow||144||\|^||Up Arrow|
|151||\Gr||Rho||152||\Gs||Lower Case Sigma|
|155||\GD||Delta Triangle||156||\PI||Upper Case Pi|
|157||\GW||Upper Case Omega||158||\||Square Dot|
|All others||\### where "###" is the three digit ASCII code of the character. For example, the euro symbol is "\160"|
|HP ASCII File Format||Back to Index|
An HP formatted text file has two main attributes. First, it probably uses trigraphs to indicates special HP ASCII symbols such as infinity and right arrow. Second, it begins with a special one line header that tells the HP what calculator settings should be used to interpret the file.
The one line header has the form "%%HP: T(t)A(a)F(r);" where t, a, and r are the translation mode, angle mode and radix mode:
|Translation Mode||Angle Mode||Radix Mode|
|0||No translation||D||Degree Mode||.||Period is used as the decimal point: 123,456.789|
|1||Translate linefeeds (ASCII #10) to carriage-return + linefeed (#13 #10)||G||Gradian Mode||,||Comma is used as the decimal point: 123.456,789|
|2||Translate some special characters. (HP ASCII characters less than 160 are translated into trigraphs)||R||Radian Mode|
|3||Translate all special characters.|
Note that while HPConnect can read files written with any translation mode and send them to the HP, when accepting files from the HP it will always uses translation mode #3.To use these trigraphs to write HP calculator software on your Mac, use your favorite text editor and use the trigraphs whenever you need a special HP symbol or character. To copy the software to the HP, make sure the text file has a proper header (for example, "%%HP: T(3)A(R)F(.);"). Next, start HPConnect normally,select ASCII transfer mode and send the file to the HP. When the HP receives the file, it will attempt to compile it into an HP object.
NOTE: Please note that if the ASCII file is not syntactically correct, the HP calculator will reject it. This is a limitation of the HP, not HPConnect.
|© 2005, Michael W. Heinz, Sr - aka "Porkchop D. Clown". All rights reserved.||Back to Index|