28  3M™ MicroTouch™ Controller EX USB Reference Guide 
 
3M Touch Systems, Inc. Proprietary Information -- 29489v05  
Response 
The parameter data is sent to the host in a Parameter Data report. All parameter data is 
treated as if it were stored as bytes. This means that multi-byte values will be sent MSB 
first.  
If the command cannot be processed, the device stalls endpoint 0. The command cannot 
be processed if the parameter number is not valid. It cannot be processed if less than 4 
bytes (wLength) are requested. It cannot be processed if more data is requested than is 
contained in the parameter. 
Parameter Data Report 4 
This report is sent in response to any request for parameter data. All parameter data is 
treated as if it were stored as bytes in the order that it is stored in memory. This means 
that multi-byte values will be sent MSB first.  
Table 20.  Parameter Data Report 
Offset  Field  Size  Value  Description 
0  Report ID  1  0x04  Report ID number 
1  Data size  2  0xXXXX  Amount of data to follow 
3  Data bytes  Data Size  0xXX  Data bytes 
Data size – the number of data bytes to follow.  
Data byte – At least 1 data byte will follow when data size is greater than zero. The 
number of data bytes returned by this report is limited by the “Max Param Write” value 
returned by the Controller ID report. The contents of this data section are dependent on 
which parameter is being accessed.