Date   : Mon, 30 Jan 1984 1116-:00CST
From   : Doug <HUNEYCUTT@gunter-adam>
Subject: Z-100 graphics..

The Z-100 dedicates 3 64K banks to RGB video display RAM.  The 6845 CRT
controller is highly programmable.  You can program the beast to display
other than the standard 225 scan lines, but you have to go into interlace
mode to do it.  Zenith's new catalog has a slow-decay color monitor for
use with interlace applications (the standard B&G and RGB monitors flicker
noticeably when interlaced mode is used).

  A point to make is that the Z-100 is always in graphics mode.  All displays
are software (or firmware) controlled.  When programmed with the standard
boot-up parameters, each character consists of 9 bytes (one per scan line).
You <can> program the controller to use up to 16 scan lines without changing
too much, which gives 400 lines/screen (25 text lines).  To go higher than
400 lines, you need to take into account the ROM address mapping scheme used
by the Z-100 to simplify screen memory accesses.

  One of the engineers said that, with 64K RAMs installed, you could technically
go higher than 800 scan lines per screen.  Don't know exactly how you'd do
that, but no matter...no screen could handle that density.  HUG has some 
demo software (SARTC, etc) that demonstrates the interlace/high density modes.

Doug