Compsee Apex III, Technical Reference Manual

Page: 91 / 168

Apex PDT Technical Reference Manual 6 Utility Programs
COAM30002 Rev. 2.00 8/13/02
6-19
Low-Level API
The basic mechanism for communicating with the installed Bar
Code Driver is via the DOS multiplex interrupt (sometimes referred
to as the TSR interrupt - Int 2Fh). All parameters are passed in
registers to the interrupt and all registers that are not shown are
undefined. Undefined registers vary by function.
All API interrupts use register ax to pass the following:
AH = our ID value (default is BCD_ID, defined as 0CEh).
AL = requested service ID
00 – install check
01 – uninstall the driver, freed memory is returned to DOS
02 – Set API option with string
03 – Scan now
04 – Query driver (future implementation)
05 – Set and use external buffer
06 – Internal (Compsee) use only
Install Check
Service 00 – Install Check
Input:
ah = BCD_ID
al = 00
Returns:
ah = BCD_ID
al = 0FFh if installed
Notes:
This function simply returns the al set to 0FFh and is used
to determine if the driver is installed. There is no
mechanism supplied to install the driver from an
application. Do NOT attempt this! The driver must be
installed from the DOS command line or a batch file such
as
[autoexec.bat] .
Uninstall
Service 01 – Uninstall
Input:
ah = BCD_ID
al = 01
Returns:
none
Notes:
Under DOS, a TSR can only be uninstalled from the
command line and can only be uninstalled if it is the last
TSR installed (DOS limitations). If possible, this function
will uninstall the driver. See
CAUTION and additional
notes on next page.