Chapter 4 — Theory of Operation
Tethered Scanner Signal Descriptions
Pin Signal Name Scanner Signal Description
1 Vext +5V in Switched scanner power: Selectable (flex option) as either:
•
5 VDC
±
5% @ 250mA maximum continuous (default)
•
Switched off when the CK30 suspends, and on low-battery.
Can be configured to stay on during Suspend, but is shut off
by hardware if the battery is critically low or removed.
Using a different tethered scan flex, this voltage can be changed
to:
•
3.3 VDC
±
5% @ 150mA maximum continuous
2 GND GND
3 Trigger* Trigger
Active-low bi-directional trigger signal. This is an open-drain
line driven and sensed by the FPGA (under application software
control) and the scanner’s trigger.
•
5V-tolerant 3.3V CMOS input and open-drain output. 20K
pull-up to SCAN_VCC.
4 Lasenable/Scan_RTS* Enable
Active-low laser enable output to tethered scanners. For decoded
scanners, this signal becomes an active-low, TTL level, serial
RTS handshake. 3.3V CMOS output. Tri-stated when
SCAN_PWR_EN is off or SCAN_PORT = 1. Can be driven in
an open-drain mode (software selectable).
5 Beep Beep
Beep output to tethered scanners. 3.3V CMOS output. Tri-
stated when BEEP_EN is off.
6 Shield GND
7 Video*/Scan_RxD* Video
Bar code video input from non-decoded scanners. Active-high
or low: only transitions are sensed.
•
5V-tolerant 3.3V CMOS Schmitt trigger input. 4.75k pull-
up to SCAN_VCC.
For decoded scanners, this signal becomes a TTL level serial
RxD input.
•
5V-tolerant 3.3V CMOS input. 4.75k pull-up to
SCAN_VCC.
•
0 = 0 or space state
•
1 = 1 or marking state
8 SOS/Scan_CTS* SOS
SOS (Start of Scan) marker from laser scanner. For decoded
scanners, this signal becomes an active-low, TTL level, serial
CTS handshake. 5V-tolerant 3.3V CMOS input. 20K pull-up
to SCAN_VCC.
9
GoodRead/Scan_TxD
*
Decode LED
Active-low bar code “Good Read” output to tethered scanners.
For decoded scanners, this signal becomes a TTL level serial
TxD output.
•
3.3V CMOS output. Tri-stated when SCAN_PWR_EN is
off or SCAN_PORT = 1. Can be driven in an open-drain
mode (software selectable).
•
0 = 0 or space state
•
1 = 1 or marking state
10 NC NC No connection.
84 CK30 Handheld Computer Service Manual
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