9be0c5b6   
   From: msmcdoug@no.spam.iinet   
      
   N Morrison wrote:   
      
   > Original Model I resolution was 128×48 (1024 characters * 6 bits)   
      
   That's the graphical resolution. To faithfully represent the TRS-80   
   character set (and hence use an unmodified port of xtrs) you need 64x6=384   
   pixels across, 16x12=192 pixels down. You also require 384x192 to support   
   the Model I "hires" graphics, such as the PCG-80 etc.   
      
   > Highest resolutions in the series with a hi-res board were 640x240 or   
   > 512x192 (I think).   
      
   The Model III hires board was 512x192, simply because the Model III   
   characters were actually 8 bits wide (64x8=512), rather than 6.   
      
   Model 4 hires was 640x240, because the Model 4 screen was 80x24 characters.   
   Characters in Model 4 mode are 8 bits wide and 10 bits high - the graphics   
   characters appear funny because the bottom 2 rows of pixels are missing from   
   each character (every 3rd row of pixels).   
      
   Using the zipit z2 would require a 5-pixel wide character set for Model   
   I/III mode (the graphics would thus be distorted). 80-column Model 4 mode   
   would be out of the question. Not sure how LCD rotation is handled and what   
   the implications are to, say, xtrs.   
      
   In a nutshell, IMHO, a bad choice of platform. A pity... :(   
      
   Regards,   
      
   --   
   |              Mark McDougall                | "Electrical Engineers do it   
   |     |   with less resistance!"   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)