Specifications

CARROLL TOUCH Chapter 5 - Smart-Frame Protocol II
Touch System Programmer’s Guide 5-17
Not Enough Parameters
If the number of command parameters is less than the number of
command parameters expected for the command, an SFP-II report
packet is sent with Cmderr pointing to the location of the first missing
parameter (the trailer).
Note that this case differs from the invalid byte count case. In this case,
the command packet byte count is consistent with the total number of
bytes in the command number and parameters, there just weren’t
enough parameters.
If the host sends the SetTouchModes (20H) command as follows to
enable touch detection and set the TouchStateReportType to the Multi
Touch State Report, but leaves off the required third parameter (the
TouchReportingMode parameter):
66 03 20 01 02 FF
The touch system responds with the following report:
E0 04 03 20 01 02 FF
The 03 byte is Cmderr and indicates that a third parameter was
expected but not present.
Too Many Parameters
If the number of command parameters is greater than the number of
command parameters expected for the command, an SFP-II report
packet is sent with Cmderr pointing to the location of the first extra
parameter.
Suppose the host sends the SetTouchModes (20H) command as follows.
The first three parameters correctly enable touch detection (01), set the
TouchStateReportType to the Multi Touch State Report (02), and set
the TouchReportingMode to Continuous (02). However, an erroneous
fourth parameter (04) is also included:
66 05 20 01 02 02 04 FF
The touch system responds with the following report:
E0 06 04 20 01 02 02 04 FF
The 04 byte is Cmderr and indicates that an extra parameter (the fourth
parameter) was present but not expected.