Carrol Touch TouchSystems CarrollTouch Prog, Руководство программиста

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Chapter 5 - Smart-Frame Protocol II CARROLL TOUCH
5-18 Touch System Programmer’s Guide
Overloaded Functions
Some SFP-II functions are overloaded in a manner similar to the way
that C++ supports overloaded functions.
An overloaded function is a function that is normally used to set the
values of some parameters, but can also be used to get the values of the
same parameters.
• To set the parameter values, the host sends the complete command
including all parameters. The touch system sets the parameters
using the values sent by the host, and returns a report that contains
the resulting values for the parameters.
• To get the parameter values, the host sends only the command
number with none of the parameter values present or a subset of
the parameter values present, depending on the function definition.
The touch system returns a report that contains the parameter
values.
If the host sends a command that includes the command number and a
partial list of parameters, it is an illegal action and an invalid parameter
error is returned in Cmderr.
For example, to get the current touch values using the SetTouchModes
(20H) command, the host sends the command as follows:
66 01 20 FF
The touch system responds with the following report:
E0 05 00 20 01 01 00 FF
This report indicates no errors in Cmderr and reports the values for the
three parameters defined for the function that were in effect when the
command was sent (
01
,
01
, and
00
). No parameter values were
changed.
However, to set the touch values using the SetTouchModes (20H)
command, the host sends the command as follows:
66 04 20 01 01 01 FF
The touch system responds with the following report:
E0 05 00 20 01 01 01 FF