Specifications

Chapter 5 - Smart-Frame Protocol II CARROLL TOUCH
5-2 Touch System Programmer’s Guide
Overview
The Smart-Frame Protocol II (SFP-II) is a firmware protocol intended
to be the successor to the existing Smart-Frame Protocol firmware
protocol, which was defined in 1985. Driving factors behind the
development of the SFP-II protocol are:
• The introduction of touch systems using guided acoustic wave
technology, which supports high resolution touch coordinates as
well as z-axis touch coordinates - features not supported by the
existing Smart-Frame Protocol.
• The need for general and architectural enhancements to the SFP.
SFP-II has been initially implemented on guided acoustic wave
systems, but is designed for and will be implemented on all Carroll
Touch systems.
Extensibility
SFP-II is designed to support true extensibility, allowing features to be
added or removed over time. It does this by providing a standard
mechanism whereby applications or drivers that interface with the
touch system can determine which features the touch system supports.
This mechanism consists of two parts: the touch system can report the
protocol version (not to be confused with the firmware version) to an
application or driver via the Protocol Version Report, and the
application or driver can use the SetReportProperties (21H) command
to request that a Report Properties Report be sent. This report includes
a parameter called FunctionVersion that can be used to determine if a
particular function is supported.
The protocol version number reflects the unique set of features
supported by that version of the protocol. Any time that a feature is
added, removed, or changed in such a way that it would be visible to the
user using the published SFP-II functions, the protocol version number
is incremented.
The protocol version number of the SFP is (retroactively) defined to be
1.0. Note, however, that because the SFP contains no mechanism for
reporting the protocol version number, SFP touch systems do not
actually respond with a Protocol Version Report. Instead, if an
application or driver receives no response when attempting to switch to
SFP-II mode using the SwitchToSFP-II (65H) SFP command, it should
timeout waiting for the command, and then assume that the touch
system only supports SFP (SFP 1.0).