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4 - 3 - 11,
Parallel Port Command
To use this command, a printer witn a standard Centronics
interface must
0e
connected to the PARALLEL port on the rear
panel.
A Centron1cs test jig may also be used in place of a
printer (see appendix).
Once a printer has been connected, first polling is used
to detect the BUSY signal,
ai1d
all available characters are
then printed.
Next, tne BUSY signal is detected using an
interrupt and, again, a full set
oi
c~aracters
is printed.
If a Centronics test jig is connect2,J, one of the data
signal lines is set to "ON", tne signal coni:cnt is looped
back to tne BUSY signal and a read check is performed.
The
STB signal is used to choose which of the eight data lines
shoula be set to "ON".
This means all data lines can be
tested.
Finally, the test determines if an interrupt was
properly generated.
diag>
parallel
-v
Set PRINTER or TEST PROBE to the PARALLEL PORT and hit <RETURN> key
PARALLEL PORT CHECK:
Write data
by
Polling ...................... OK
Write data
by
Interrupt .................... OK
diag>
Printer connected
diag>
parallel
-v
Set PRINTER or TEST PROBE to the PARALLEL PORT and hit <RETURN> key
PARALLEL PORT CHECK:
diag>
Data lines all Low ......................... OK
Data lines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . OK
Interrupt . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . OK
Centronics test jig connected
NWS-1510/1530/1580
4-19
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