Atari 400 Technical Reference Manual page 44

PUT CHARACTERS and PUT RECORD
The handler accepts display data in the following screen mode
dependent forms; there is no facility for the handler to receive
graphics data in packed form.
Figure 5-7
7 °
+-+-+-+-+-+-+-+-+
ATASCII
+-+-+-+-+-+-+-+-+
+-+-+-+-+-+-+-+-+
C D
+-+-+-+-+-+-+-+-+
+-+-+-+-+-+-+-+-+
? I -D I
+-+-+-+-+-+-+-+-+
+-+-+-+-+-+-+-+-+
? IDI
+-+-+-+-+-+-+-+-+
+-+-+-+-+-+-+-+-+
?
D
+-+-+-+-+-+-+-+-+
Mode 0
Modes 1,2 -- C = color/data
set,
D = truncated ATASCII.
Modes 3,5,7 -- D
=
color.
Modes 4,0,8 -- D
=
color.
Modes 9,10,11 -- D
=
data.
Graphics Mode 3-11 PUT Data Form
NOTE: For all modes, if the output data byte e~uals $9B (EOL), that
byte will be treated as an EOL character; and if the output
data byte
e~uals
$7D (CLEAR) that byte will be treated as a
screen-clear character.
The cursor moves to the next cursor position as each data byte is
written. For mode
0,
the cursor will stay within the specified
margins; for all other modes, the cursor ignores the margins.
While outputting, the Display Handler monitors the keyboard to
detect the pressing of the [CTRLJ
1
key combination. When this
occurs, the handler loops internally until that key combination
is pressed again: This effects a stop/start function that
freezes the screen display. Note that there is no ATASCII code
associated with either the [CTRLJ
1
key combination or the
start/stop function. The stop/start function can be controlled
only from the keyboard (or by altering database variable CH as
discussed in Appendix L, E4).
OPERATING SYSTEM C010555 -- Section 5
59