Intermec 073297-001 User Manual
Chapter 4 — Theory of Operation
boots. The factory-set default is restored if the registry is lost or “Restore
Defaults” is selected from the Configuration Menu.
Defaults” is selected from the Configuration Menu.
Temperature Compensation
Temperature compensation is implemented in the software display driver,
using temperature information read through the PSC to vary the duty
cycle of the PWM output.
using temperature information read through the PSC to vary the duty
cycle of the PWM output.
Backlight
Software turns the backlight on and off through HCR register U16 signal
BKLT_ON.
BKLT_ON.
The monochrome display uses an EL backlight with drive circuitry built
into the display module. The color display uses a white LED backlight
driven by backlight driver U48. Since U48 is stuffed on all PCB
assemblies, gate U27 senses when a monochrome display is installed and
disables U48 for power savings.
into the display module. The color display uses a white LED backlight
driven by backlight driver U48. Since U48 is stuffed on all PCB
assemblies, gate U27 senses when a monochrome display is installed and
disables U48 for power savings.
Backlight High/Low intensity control (supported on the white LED
backlight only) is controlled through HCR register U11 signal
BKLT_LOW using U48 RSET pin.
backlight only) is controlled through HCR register U11 signal
BKLT_LOW using U48 RSET pin.
Keypad
The CK30 computer supports replaceable keypads of up to 63 keys (plus a
handle trigger) arranged in an 8 x 8 matrix scanned from the PXA255
processor. Currently three keypad styles are defined: 42-key, 50-key and
52-key. The keypad itself is a low-profile elastomeric keypad with
conductive carbon pucks, similar to the M90 keypad. It is adhesively
attached to the top surface of the CK30 top cover and connects to the
main PCB connector J11 through a hole in the top cover. This facilitates
keypad replacement in the field.
handle trigger) arranged in an 8 x 8 matrix scanned from the PXA255
processor. Currently three keypad styles are defined: 42-key, 50-key and
52-key. The keypad itself is a low-profile elastomeric keypad with
conductive carbon pucks, similar to the M90 keypad. It is adhesively
attached to the top surface of the CK30 top cover and connects to the
main PCB connector J11 through a hole in the top cover. This facilitates
keypad replacement in the field.
Key Matrix Scanning
Keys are arranged in an 8 x 8 matrix. Row,Column position (0,0) is
reserved for the handle trigger reed switch, which connects to the main
PCB through connector J4.
reserved for the handle trigger reed switch, which connects to the main
PCB through connector J4.
The eight column lines KEY_DRV7:0 are driven from PXA255 GPIO
pins (GPIO73-GPIO66) configured as open-drain outputs. The 8 return
(row) lines KEY_RET7:0 are pulled up through 10K resistors and
monitored through the FPGA.
pins (GPIO73-GPIO66) configured as open-drain outputs. The 8 return
(row) lines KEY_RET7:0 are pulled up through 10K resistors and
monitored through the FPGA.
The FPGA incorporates a memory-mapped register for software to read
the state of KEY_RET7:0. It also includes interrupt logic that, when
enabled by software, interrupts the processor on any edge of
KEY_RET7:0.
the state of KEY_RET7:0. It also includes interrupt logic that, when
enabled by software, interrupts the processor on any edge of
KEY_RET7:0.
CK30 Handheld Computer Service Manual
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