From: RDC@oz.org   
      
   Frank Durda IV  wrote in message ....   
   ...Sat, May 2 1998 12:00 am   
      
   "The Model 4/4D/4P used a masked version of the Motorola MC 6845 Video   
   controller, a device eventually copied by just about everyody else.   
   It is the basic video controller in the original IBM PC, and all PC video   
   cards since then mimic the 6845 registers (zero thru 15) to provide PC   
   compatibility.   Getting information about The 6845 should therefore be   
   incredibly easy.  All of the Tandy 1000 and up technical reference manuals   
   have programming information on these registers.   
      
      
   However, Tandy elected to use a masked part in the Model 4 series, called a   
   68045, where some of the registers contain hard-coded values and cannot be   
   changed.  In particular, the registers controlling the number of rows and   
   columns, horizontal and vertical sync, are preset.  By raising and lowering   
   a   
   pin on the 68045, you can select between two hard-coded sets of values,   
   which Tandy used for the 64x16 and 80x24 screen dimensions the Model 4   
   supports.   
      
      
   Somewhere around I have the masked settings that Tandy ordered for these   
   devices if you are really interested."   
      
   -------------------------------------   
      
   Hi Frank,   
      
   Going back a ways I know...   
      
   Do you still have the mask settings for the 68045 part by any chance?   
      
   Would be most appreciated if you do.   
      
      
      
   Cheers,   
      
   Leslie   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)