Remember:
This program only modifies the Viewmaster 80 cursor.
The 40 column cursor is generated by the computer and is merely
"passed through" the Viewmaster 80 (Statement 10 of the program
ensures the Viewmaster 80 is activated).
The Viewmaster 80 cursor is actually made up of 9 rows of horizontal
lines. These rows are numbered 0 through 8, starting at the top.
Statements 40 and 50 in the example program determine the
beginning (FIRST) and ending (LAST) rows to be displayed. In the
program example shown, the cursor becomes a small square block,
consisting of rows 2 through 5. Rows 0, 1, 6, 7, and 8 are blank. This
is illustrated in the picture following.
The Viewmaster 80 cursor blink rate can be varied from steady to
fast, or turned off entirely by changing the "BLINK =" value in
statement 30. The allowable values and their functions are:
BLINK = 0
Steady; non-blinking cursor
BLINK = 32 Cursor OFF
BLINK = 64 Fast blinking cursor
BLINK = 96 Normal blinking cursor
ViewMaster 80 Graphics Display
When the Viewmaster 80 is active, the 80 column text display is
generated by the Viewmaster 80, not by the Apple's 40 column video
circuitry. But the graphics displays, accessed via the GR, HGR, and
HGR2 commands, are generated by the Apple and must be passed
through the Viewmaster 80. In 40 column mode this is done
automatically. In Viewmaster 80 mode, all graphics display routines
must be preceded with a POKE 49330,0 to flip the graphics display
soft switch on the Viewmaster 80, allowing the graphics to pass
through. Any subsequent character output to the Viewmaster 80 will
automatically flip the soft switch back to 80 column text mode.
20
ViewMaster 80