Date   : Tue, 23 May 1989 22:12:39 GMT
From   : atha!auvax.AthabascaU.CA!tech@decwrl.dec.com (Richard Loken)
Subject: TRS80 Model II 40 column screen mode

TRSDOS for the Model II has a control code to switch the console into 40 column
mode and another to switch it to 80 column mode.

I have used this phenomenon when writing BASIC programs in TRSDOS but I
recently
tried to do this under P&T CP/M and found there is no such feature.  Undaunted
I searched the TRS80 manuals to find out how this mechanism is handled - but in
vain.  I phoned TriSoft to find out if CP/M handles this feature in some 
obscure manner but they didn't seem to know that the Model II had a 40 column
mode and suggested it might have be done by building characters out of the 
graphics character set.

I am unsatisfied with the graphics theory (mostly because I would have to write
a bunch of code to build my new bigger character set).  It appears to me that 
in 40 column mode the character set is identical but built out of bigger dots.

So..  Daddy, how does Tandy put bigger characters onto the TRS80 Model II?  
If this is a hardware feature can you provide enough hard information for me
to get this running under CP/M?

Are there any 8 bit afficianados out there?

     *********     73
    **********     Richard Loken VE6BSV
   .      ****     
  ..      ****     Athabasca University
 ....     ****     Athabasca, Alberta Canada
..........****     tech@athabascau.ca    alberta!auvax!tech