Synaptics Touchpad Interfacing Guide (ACF126)
This guide describes how computers and other hosts interface to the Synaptics TouchPad.
The first section describes the TouchPad generally, including operating modes, features, host interactions, and principles of operation, with many historical notes comparing older versions of the Synaptics TouchPad with the present one, version 4.5.
The Synaptics TouchPad family supports a variety of protocols for communicating with the host computer. The next few sections describe the available protocols:
• The PS/2protocol is the method that most portable computers use to interface with keyboards and pointing devices.
• The Serialprotocol connects the pointing device to the host using a standard RS-232 serial port.
• The ADBprotocol is used by Apple Macintosh family computers. (See page 64.) In each case, the TouchPad supports the industry standard “mouse” protocol plus a number of TouchPad-specific extensions. This Guidedescribes the PS/2 and Serial protocols in complete detail, and the ADB protocol in all details not covered by Apple publications. System architects and developers can read these sections of the Guideto learn how to interface to the TouchPad hardware. (For detailed mechanical and electrical data, refer to the various Model TM41xx Product Specificationsheets also available from Synaptics.)
Most operating systems provide driver software to handle the TouchPad at the hardware level. Software developers will be more interested in the TouchPad Driver API, a highlevel interface that Microsoft Windows applications can use to take advantage of all the special abilities of the Synaptics TouchPad and the Synaptics drivers.