Datasheet

nugget Theory of Operation
4-3
4
This appendix contains the theory of operation for the 241X.
Main PCB
The main PCB contains the primary circuitry for the Trakker Antares
®
terminals. It also
contains the Vadem VG-230, which is a PC/XT compatible processor. The functions of
the main PCB are:
• Processing keyboard input
• Processing output data to the liquid crystal display (LCD)
• Processing decoded bar code data from the scanner interface
• Processing decoded bar code data from the linear imager interface
• Providing radio communication interface (2415 only)
• Providing serial communication or input to devices such as wand scanners using
the COM1 external interface port
The main PCB also provides interfaces to the main battery and backup battery. The DC
power supply provides all necessary voltages to operate the terminal.
Liquid Crystal Display (LCD) Interface
The VG-230 supports the FRAME, LOCLK, M, LCDU(0-3), and SHCLK signals for
the LCD interface. The low battery LED is controlled independently from the ASIC
while the remaining ICON interfaces are controlled from the ASIC using ICON-CLK,
ICON-DATA, and ICON-CS. Discrete signals to the LCD include LCDEN, VPBIAS,
LCD-CTRL, and LCD-ADJ. Backlight Signals are BACKLT-ON and BACKLT-HIGH.
The LCD is powered from VCCBL, which is generated from VBAT, and VCCLCD,
which is switched from VCC230A with the VPLCD signal.
Keyboard Interface
The Vadem VG-230 provides a scanned keyboard interface to the keypad. The keypad
has a SUSPEND/RESUME button that is routed to the VG-230. An EXT interrupt is
created and toggles the processor into a low power mode.
The keypad provides a TRIGGER* interface for the scan button at the top of the
keyboard. The TRIGGER* is processed to enable bar code scanning.
To generate a hard reset and reboot of the terminal
• Press and hold the _ key until the Good Read LED lights up for longer than 8
seconds.