When the IBM-PC BASIC interpreter sends hex code OD (carriage re-
turn) it adds an extra hex OA (line feed). Hex code 1A (end-of-file) also gets
special treatment: the interpreter does not send it at all. This can cause
problems in programs that generate graphics or download character data,
but there is a solution. Try changing line 20 in the preceding program and
adding the coding shown below.
Coding for IBM-PC with monochrome display:
20 GOSUB 100
100 O=INP(&H3BD) : IF 0<128 THEN 100
110 OUT &H3BC,I :OUT &H3BE,5 :OUT &H3BE,4
120 RETURN
Coding for IBM-PC with colour adaptor:
20 GOSUB 100
100 O=INP(&H379) :IF 0<128 THEN 100
110 OUT &H378,1 :OUT &H37A,5 :OUT &H37A,4
120 RETURN
SWITCH COMBINATION FUNCTIONS
Several additional functions can be obtained by pressing the control
panel switches in combinations.
COURIER 0
SANSERIF 0
ORATOR 0
Reverse micro-feed
! Top of form
Figure 2-7. Switch combination functions of control panel