Intermec 073290-001 User Manual

boots. The factory-set default is restored if the registry is lost or “Restore 
Defaults” is selected from the Configuration Menu. 

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. 

Software turns the backlight on and off through HCR register U16 signal 
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. 

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. 

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. 

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. 

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. 

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.