14
Trigger
Driving the nTrig pin (PIN 12) on the host interface connector low for over 10ms causes the EM1399-LD
to start a scan and decode session. If barcode is decoded, the EM1399-LD waits for the voltage at the
nTrig pin to turn high (or the trigger to be released) after sending the data to the Host. If the trigger is
released during a scan attempt, the EM1399-LD immediately stops decoding.
Next decode session does not happen until the EM1399-LD receives active trigger signal (driving the
nTrig pin low) again.
As a decode session involves image capture, barcode decoding and other steps, it is suggested that the
minimum interval between two triggers should exceed 50ms.
The following trigger circuit is provided for reference.
B3F-4000
S1
2
3
1
4
5
6
C3
100pF
CBW1608/60R
L1
C4
100pF
nTrig
R15
10K
VDD
