Intermec 073292-001 用户手册
Chapter 4 — Theory of Operation
Standard asynchronous serial signals TxD, RxD, RTS and CTS are
multiplexed onto the 10-pin scanner connector as shown in the “Tethered
Scanner Signal Descriptions” table on page 84, and routed through the
FPGA.
multiplexed onto the 10-pin scanner connector as shown in the “Tethered
Scanner Signal Descriptions” table on page 84, and routed through the
FPGA.
SCAN_RTS and SCAN_CTS are accessed by software through memory-
mapped FPGA registers when the FPGA scanner interface is configured
for serial scanners. SCAN_TXD and SCAN_RXD are routed through the
FPGA to the “ST” UART on the PXA255. The operating system maps
this UART as COM3.
mapped FPGA registers when the FPGA scanner interface is configured
for serial scanners. SCAN_TXD and SCAN_RXD are routed through the
FPGA to the “ST” UART on the PXA255. The operating system maps
this UART as COM3.
Scanner Power
3.3V and 5V scanner power is controlled through HCR register U11
output SCAN_PWR_EN*. The 22-pin scanner port supports only 3.3V
scanner power. The 16-pin scanner port supports both 3.3V and 5V
power. SCAN_PWR_EN* switches both supplies on and off
simultaneously through high-side switches U12 and U13; the voltage
appropriate to the installed scanner is selected through the scanner flex
wiring. A loopback pin on the connector feeds the selected voltage back to
the interface’s pull-up resistors.
output SCAN_PWR_EN*. The 22-pin scanner port supports only 3.3V
scanner power. The 16-pin scanner port supports both 3.3V and 5V
power. SCAN_PWR_EN* switches both supplies on and off
simultaneously through high-side switches U12 and U13; the voltage
appropriate to the installed scanner is selected through the scanner flex
wiring. A loopback pin on the connector feeds the selected voltage back to
the interface’s pull-up resistors.
5V power for tethered scanners attached through the docking connector
(TETH_SCAN_VCC) is controlled by HCR register U11 output
DOCK_EN through high-side switch U13.
(TETH_SCAN_VCC) is controlled by HCR register U11 output
DOCK_EN through high-side switch U13.
Tethered Scanners
Decoded-output tethered scanners and undecoded (DBP) tethered
scanners are supported through an optional 10-pin Stewart connector built
onto a flex circuit that plugs into 16-pin scan port J3.
scanners are supported through an optional 10-pin Stewart connector built
onto a flex circuit that plugs into 16-pin scan port J3.
• Undecoded tethered scanners use the FPGA count gathering interface
• Decoded scanners are supported as serial (TTL-level RS-232) devices
(See “Serial (RSTTL) Scanner Interface” on page 82).
• Decoded scanners may also be supported as wand emulation or laser
emulation devices (see “Wands and Wand Emulation” on page 80), but
serial is preferred to minimize power consumption, and avoid speed and
buffer size limitations.
serial is preferred to minimize power consumption, and avoid speed and
buffer size limitations.
Laser interface and TTL-level serial signals are supported at the 10-pin
Stewart connector using Intermec’s standard pin-out (except that no
battery power is provided on pin 10):
Stewart connector using Intermec’s standard pin-out (except that no
battery power is provided on pin 10):
CK30 Handheld Computer Service Manual
83