Siemens SIMATIC HMI SICALIS PMC 7 Equipment Manual page 51

Restrictions in the selection of the code
The 8042 keyboard controller and the Windows NT keyboard driver:
In the selection of the MAKE and BREAK codes, the following restrictions must
be noted:
– The key codes must lie between 1h and 7Fh.
– The prefix F0h causes the keyboard controller to set Bit No. 7 when handling
the next Byte. Windows NT interprets this as the release of a key.
– The prefixes E0h and E1h are also permissible.
Key Code Recognition by the Driver File, SiKey.sys:
The following restrict only applies when the codes used should also trigger a bit
action:
If a code consists of both a key ( e.g. F1) and a combination code ( e.g. ALT),
the combination code may not begin with the same sequence as the short
code. In this case, the key codes should be extended with codes, which
Windows NT does not recognize.
Example:
The key code for releasing key F1 is BBh, for releasing the Shift key AAh.
Releasing the key combination Shift-F1 thus send the combination code BBh
AAh.
The keyboard driver interprets the code BBh as indicating that the key F1 has
been released. Thus the system will never recognize that the key combination
Shift-F1 was released.
Solution: Extend the code for the F1 key e.g. by the code E1h 01h.
Compiling a Keyboard Mapping Table
The keyboard mapping table is required, when keyboard controller does not use
standard MAKE/BREAK codes and an application expects virtual key codes from
these keys.
The keyboard mapping table is a 32-bit Windows DLL. The table is created by
compiling and linking a C file. To do so, you will need a MS C 32-Bit compiler and
Windows NT DDK for Windows NT 4.0.
Keyboard Mapping Table Installation
After compiling, copy the file, KbdTaco.dll, into the Windows NT directory
\System32.
In the Start menu, activate the keyboard mapping table from
\Settings\Control Panel\Keyboard. On the Input Locales panel,click on
the Properties button and select the Keyboard Layout, TacoKeyboard .
SICALIS PMC 7 Operator Panel Equipment Manual
Release 09/00
Developer Version
C-5