15
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I = Input; O = Output
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1 This external trigger signal can be either level trigger or pulse trigger.
Level trigger:
The trigger signal is generated via the external trigger pull or the external IO interface. A trigger pull
activates a decode session (duration:
≥
25ms). Ensure the level of trigger signal maintains unchanged during the
decode session.
Pulse trigger:
When the trigger signal is detected, scanning is activated until a barcode is decoded or the decode
session timeout expires (pulse width:
≥
25ms). The duration can be programmed. To learn how to program the
parameter, please see the EM20-85 user guide.
For the external trigger circuit
, please see the “Trigger Circuit” section in Chapter 5. If the EXT_TRIG# pin is not used,
leave it unconnected.
※
2 Giving a 20
μs low pulse on the EXT_RST# pin of the 12-pin FPC connector will reset the engine. If this pin is not used,
leave it unconnected.
※
3 This output signal can be used by an external LED to indicate good read status.
The EXT_DSF pin produces a high output (default duration: 20ms, user-programmable) when a good read occurs. To
learn how to program these parameters, please see the EM20-85 user guide.
For the external LED circuit
design, please see the “Good Read LED Circuit” section in Chapter 5. If the EXT_DSF pin
is not used, leave it unconnected.
※
4 This output signal can be used by an external beeper circuit to generate audible feedback to the user to indicate
power-on and good read statuses.
Power On beep:
The EXT_BUZ pin produces a PWM output (duration: 400ms; frequency: 2090Hz, 2630Hz, 3130Hz
and 4260Hz.) 215ms after power-on. The beep can be programmed On or Off. To learn how to program the parameter,
please see the EM27 user guide.
Good Read beep:
The EXT_BUZ pin produces a PWM output (default duration: 80ms; frequency: 2710Hz, 3940Hz,
4800Hz) when a good read occurs. Default frequency is 2710Hz. The beep can be programmed On or Off. To learn
how to program these parameters, please see the EM27 user guide.
For the external beeper circuit design, please see the
“Beeper Circuit” section in Chapter 5. If the EXT_BUZ pin is not
used, leave it unconnected.
