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3M™ Multi-Touch Chassis Display User Guide
3M Touch Systems, Inc. Proprietary Information -- 37732v04
Table 7. Power On Check Bit Fields
Bit Number
Description
Notes
0 Not
used
1
ROM_ERROR
Code area checksum error
2
PWM Error
Touch screen not connected or potential problem
3
NOV_ERROR
Parameter blocks checksum error
4
HDW_ERROR
Problem with ADCs
5--7 Not
used
Command Status – The status for the last command request. This field is used to
determine whether the last request was processed successfully. It is also used to track the
progress of a multi-stage request, such as 2 point calibration. The Status Request does not
affect the contents of this field, i.e., successful or unsuccessful processing of a previous
status request does not cause the command status field to be updated.
Table 8. Valid Command Status Field Entries
Response
Description
0
Failure in command processing
1
Command being processed
2
Stage 1 processing complete (for multi-stage commands)
3 Command
complete
4
Soft Reset Occurred
5
Hard Reset Occurred
6 -- 7
Not used
Get Feature - GetMaxCount
This is a request to send information that indicates the maximum number of simultaneous
touches supported by the controller.
Table 9. Setup Stage
Offset
Field
Size
Value
Description
0 bmRequestType
1
0xA1
Class,D2H,Interface
1 bRequest 1
0x01
Get
Report
2 wValue
2
0x0312
msb=03=Feature
lsb=12 Feature Report ID
4 wIndex
2
0 Always
0
6 wLength
2
2 Always
2
Table 10. Data Stage (controller response)
Offset
Field
Size
Value
Description
0
Report ID
1
0x12
Feature Report ID
1 Max
Count 1
0x1E
Number
of actual fingers supported
Note:
The number of actual contacts reported may exceed this number.