3M™ Multi-touch Display M2256PW User Guide

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POC Status – The status of the Power-on Checks. Various controller systems are checked at power-up. If any failures in these systems are detected, a POC flag is set. The POC status field reports the state of these flags.

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

 

Cmd 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

3M Touch Systems, Inc. Proprietary Information – 37531 Rev D

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3M M2256PW manual Get Feature GetMaxCount, Power On Check Bit Fields Bit Number Description