User`s manual

A data dump printout of a program shows exactly what the printer
is receiving, regardless of what the computer is sending. The following
program run in the data dump mode can show how the Apple IIc and
ProDOS BASIC handle certain codes.
5 PRINT CHR$(4);"PR#1"
10 FOR X=125 TO 200
20 PRINT CHR$(X);
30 NEXT X
300 PRINT CHR$(4);"PR#0"
After you type this program, put the printer in data dump mode
and run the program. Remember to press the ON LINE button to
make the LX-90 print the final line.
Data Dump Mode
0000 7D 7E 7F 00 01 0 2 03 OD OA 07 53 59 4E 54
41 58 }~........SYNTAX
0001 20 45 52 52 4F 52 OD OA OD OA 42 52 45 41
4B 07 ERROR....BREAK.
0002 20 49 4E 20 32 30 OD OA 5D
Now compare the printer with the list of hex codes on pages A-2
and A-3. The first three codes in line 0000 (7D, 7E, and 7F) are equiva-
lent to decimal codes 125, 126, and 127, so those codes are transmitted
normally. The next four codes (00, 01, 02, and 03), however, show
that the eighth bit has been made equal to zero.
The code after 03 should be 04, but since the IIc has a special pur-
pose for that code, it is not sent to the printer; instead it causes a
syntax error, as you can see by reading the guide section. (Because of
the syntax error you must press control and reset to return keyboard
output to the screen.)
The data dumping capability can help you find problems and debug
programs quickly.
E-9