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© 2003 Wasp Technologies, Inc.
COM Manager
The COM manager controls the communication link between the WDT2200 and
the host through a RS232 serial port.
LOADER
The function of the loader is identical to that of the MSDOS loader except for the
memory allocation/de-allocation scheme being simplified. The loader's operations
are:
1. read .exe header
2. find enough memory for .exe
3. read binary into RAM
4. relocation based on RAM allocation
5. set up all registers
6. jump to the entry point
LCD Manager
The LCD manager handles the cursor positioning and graphic pattern display.
Two character pattern fonts are supported. The WDT2200 can support both 6x8
font
(20 column by 8 lines)
and 8x16 font
(16 column by 4 line)
.
EXEC
The EXEC is the job scheduler. It manages top-level operation flow of the
WDT2200 system. The EXEC program is analogous to the COMMAND.COM
program in MS DOS-based machines.
2.3 Operation Flow
The EXEC program controls the WDT2200. When the portable terminal is powered up, EXEC
performs the power-on-test (POT). EXEC proceeds to verify if the WDT2200 should make a warm
or cold booting. A
warm boot
resets the system without clearing any RAM program or data files.
Device configurations preserve the same values as they had before the warm boot. On the other hand,
a
cold boot
will clear the RAM and initialize the WDT2200 to default values.
The WDT2200 is always testing its main and backup batteries. The LCD will display a warning
message when the test fails.
Power on Test
Test failure message
Main battery test
"WARNING MAIN BATTERY LOW"
Backup battery test
"WARNING LITHIUM BATTERY LOW"
When the main battery is low, a warning message will be displayed on the LCD when THE
WDT2200 is power on. For THE WDT2200, it can automatically detect battery status, a warning
sign will be display on battery icon on the upper side of LCD.
During the start-up process, EXEC also initializes the WDT2200 barcode scanner and RS232
communication port, and creates all dynamic data structures; e.g. keypad queue and COM buffer.
