3M M2256PW 用户手册

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3M™ Multi-touch Display M2256PW User Guide 

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

AD 

 Indicates the PX series of controllers 

Ffff  =  Four ASCII characters that indicate the features supported by the 

controller. 

****  Indicates no additional features configured 

Ss 

=  Two ASCII characters that provide status information about the 

controller hardware. The two characters represent one byte. Each 
character is in the range 0 to 9 and A to F. 

Table 2 defines the meaning of each bit in the status byte. Each bit 
can be set to 1 or 0, where 1 = an error and 0 = no error. So a 
response of: 

00 = No diagnostic errors (normal response) 

The PX running with no errors returns the following string: 

<SOH> AD****00 <CR> 

The format includes two bitmapped ASCII hex status bytes.   A “00” indicates no errors.   

0 Not 

used 

 

1 

ROM_ERROR 

Code area checksum error 

2 

PWM Error     

Touch screen not connected or potential problem. 

3 

NOV_ERROR        Parameter Block1 checksum error 

4 

HDW_ERROR 

Problem with ADCs 

5 

Not used      

 

6 

Not used      

 

7 

Not used      

 

The format is a six byte packet that includes one status byte, four bytes of binary X,Y 
position data and a touch ID.  The X,Y coordinates are 14 bits, providing a range of 0 to 
16,383. The data is sent in the following format: 

Status - Byte 1 

1 

P

1

0

0 0 0 0

0

X 

- 

Byte 

2 

0  X6 X5 X4 X3 X2 X1 X0 

X 

- 

Byte 

3 

0 

X13 X12 X11 X10 X9  X8  X7 

Y 

- 

Byte 

4 

0  Y6 Y5 Y4 Y3 Y2 Y1 Y0