Function Code 0 — Set Video Mode - Zenith Z-100 Reference Manual

Function Code 0 — Set V i deo Mode
To set the desired video mode, a value from 0 to 7 is placed in the AL register
before implementing the interrupt command. The recognized modes and their
function codes are presented in Table 7.18.
Table 7.18. Video Mode Function Codes
FUNCTION
CODE
0
output.
2 8 0
80 characters x 25 rows, monochrome display at the RGB
output.
video pages.
80 characters x 25 rows, color display at the RGB output.
Individual text pages may be scrolled.
4 ltd
320 x 200 pixel resolution, color at the RGB output.
Text emulation capability for 40 x 25.
5
gC
320 x 200 pixel resolution, monochrome at the RGB output.
40 x 25 text emulation.
$;6
640 x 200 pixel resolution, monochrome at the RGB output.
All three scrolling modes available (see scrolling selection).
80 x 25 text display on a monochrome display adapter card.
Function Code 1 — Select Cursor Type
To set cursor type, load bits 0 to 4 of CH with the starting scan line value and
load bits 0 to 4 of CL with the ending scan line value. While it is possible to
load a value between 0 and 31, characters are normally eight scan lines tall,
so it is advised that values in the range 0 to 7 be used. Also, the starting scan
value may not be greater than the ending scan value.
Function Code 2 — Select Cursor Position
Load DH with the desired cursor row number, and DL with the column number.
= 0 places the cursor in the uppermost left-hand position
= 0 and DL
DH
of the screen. Load BH with the desired video page number, consistent with the
video mode selected. Also see information on setting the video page display func-
tions.
VIDEO MODE DESCRIPTION
40 characters x 25 rows, monochrome display at the RGB
40 characters x 25 rows, color display at the RGB output.
Individual video pages may be scrolled without affecting other
Video Graphics Programming
Page 7.35