BB2TD DEFAULT SCAN CODES
Each matrix point of the BB2TD 8 * 8 digital touch panel matrix has an default scan code. The default scan codes are stored in the touch panel scanner scan code table. This table is a part of the touch panel scanner firmware. If the user presses a touch panel key, the touch panel scanner transmit the default scan code to the PC/104 CPU keyboard interface.

When a touch panel key is pressed, the touch panel sends the default scan code for KEY DOWN (bit7 = low) over the serial link to the motherboard keyboard controller on the PC/104 CPU. If the touch panel key is released, the touch panel scanner sends the default scan code for KEY UP (bit7 = high) to the motherboard keyboard controller.

In Microsoft Windows- based applications for the BB2TD, the default scan code is the OEM Scan Code for Windows keystroke messages. If a user presses and releases BB2TD touch panel keys, the BB2TD touch panel scanner passes the keystrokes to Windows. Windows saves the keystrokes in the system message queue and then transfers them to the message queue of the program with the input focus. Together with all keystroke messages, Windows passes a 32- bit parameter lParam to the window procedure of the program with the input focus. This parameter contains six fields. One field is the OEM Scan Code. The OEM Scan Code is the default scan code of the BB2TD touch panel scanner.

SSV SOFTWARE SYSTEMS PC/104 Products. BB2TD DSC. File: P43.HTM, Last Update: 18-Sept-1997
Copyright (c) 1996, 1997 WST. All rights reserved.