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Chapter 5 - Smart-Frame Protocol II CARROLL TOUCH
5-8 Touch System Programmer’s Guide
The bytes within the command packet are indexed beginning at 0 for
the SFP-II command number, and ending at (command packet byte
count - 1) for the last parameter byte. The length of the command
packet is given by the packet byte count from the validation layer.
Example
A simple example of an SFP-II command is the GetTouchState (01)
command, which has one byte of data and no optional command
parameters, is:
66 01 01 FF
A more complex example of a SFP-II command is the imaginary Fubar
command, which expects a one byte parameter (bip) and a two byte
parameter (flap):
66 04 <Fubar> <Bip> <FlapHi> <FlapLo> FF
If the command opcode for Fubar is 27H, and the values of the Bip and
Flap parameters are 18H and 8923H, respectively, the command packet
is as follows:
66 04 27 18 89 23 FF
Reports
An SFP-II report has the format:
header packetbytecount commanderrorstatus
reportnumber optionalreportparameters trailer
header
= Defined to be EOH.
packetbytecount
= Length of the report the command error status
+ the report parameters (if any) in bytes. For example, a
report with two bytes of parameters would have a byte
count of 4 (one byte for the command number, one byte
for the command error status, and two bytes for the
parameters).
commanderrorstatus
= A one byte parameter that indicates whether the SFP-II
command number and/or the SFP-II command