Epson PX-8 - Page 118

REV.-A
read, while FRC continues counting until another interrupt by the BRDT trigger pulse occurs. The
next pulse repeats the operation. In this manner, the main CPU can accurately read the barcode
pattern data by means
of software.
The BRDT signal is also connected to the A-D converter; converter output is used to examine the
barcode data signal for any unacceptable deviation from the nominal voltage levels and has noth-
ing to do with data read.
R52
TRIGo-----~----------~r_--------------~------~P62
10K
Analog interface AN I N IJ------t--..>--------------,
GND~
R106
100K
R107
100K
J4
9
ONI/OFF
+5
+5
C33rl;
10K 5.1 K
Barcode interface
R23
2.2K
Q10
+5u------.~~--~
+
C2
2
VB
3
120
Fig. 2-96 Barcode Interface Circuit
2-94
C3~
(2E)
7508