Specifications
For
instance,
if
the x-co-ordinate
is
outside the
range
0
to
80, the cursor will
be
left
at
the
left
edge
of
the screen
at
the line specified
by
the y-co-ordinate. Bit 7 of the
address bytes
is
ignored,
offsets
of
8OCHEX)
do
not
change
the address value.
2.
Some
language processors will
not
properly address
column
9 or line 9
when
using the
Cursor
Address
facility,
because they automatically
expand
a "09"
code
into a
TAB,
and
insert
several spaces.
The
suggested solution
is
to
add
an
offset
of
80(HEX)
to
both
the x-
and
y-co-ordinates, since the terminal emulator ignores the top
bit
of the address.
3. Cursor
Up
will
have
no
effect
if
the cursor
is
positioned
on
line
O.
4. Cursor
Down
will perform a
scroll
(ie.
entire
screen
up
one
line)
if
the cursor
is
positioned
on
the
bottom
line of the in-use screen.
5.
Cursor
Right
has
no
effect
if
the cursor
is
positioned in
column
80.
6.
Cursor Left will
have
no
effect
if
the cursor
is
positioned in
column
0 of
any
line.
7. In the
CP/M
2.2 terminal
drivers,
there are
27
lines (0-26)
and
80
columns
(0-79)
on
the
60Hz
video
driver,
and
35
Co-34)
lines
and
80
columns
in the
50Hz
video driver.
8.
The
Televideo
920
"Half-intensity" control
codes
perform the
same
effects
as the "Reverse
Video"
control codes.
The
Televideo
920
"Clear Screen"
code
performs a "Clear Screen
and
Home"
•
9.
Programs
using these control
codes
should
be
made
flexible
as additional control
codes
may
be
implemented
in the future.
Megatel
Computer
Technologies Toronto,
Canada
Appendix
Page
A-18