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3M™ MicroTouch™ Controller RX142 Reference Guide

3M Touch Systems, Inc. Proprietary Information

The low order bits (X3 – X0 and Y3 – Y0) are not significant in a 1024 by 1024 sensor

because data can fluctuate with each touch, and therefore may not be completely

accurate.

Table 4 Data Sequence

MSB

Bits

LSB

Data Sequence 7

6

5

4

3

2

1

0

S

Byte 1

1

S6

S5

S4

S3

S2

S1

S0

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

Y

Byte 5

0

Y13 Y12 Y11

Y10

Y9

Y8

Y7

Table 5 defines the status bits (Byte 1) for the Format Tablet data.

Table 5 Format Tablet Status Bits

Bit

Description

Values

S0 – S5 Reserved

—

S6

Proximity (touch state) 1 = Sensor is being touched (a touchdown or a continued touch).

0 = Sensor is not being touched (a touch liftoff or inactive).

When the proximity bit changes from 1 to 0 (touch liftoff), the

controller outputs one final set of X/Y coordinate data with the bit

equal to 0 and the X/Y coordinate data equal to the last touch point.

S7

Packet synchronization Always 1.

Get Controller Number

Syntax:

<SOH>Q002<CR>

Response:

<SOH>XXXXXXXX<CR> Where each X is a hexadecimal digit, most significant digit

first.

Description:

This command is used to get a controller number for applications use. The controller does

not use this value. This is useful for identifying individual controllers in a multiple

controller system.

Mode Stream

Syntax:

<SOH>MS<CR>

Response:

<SOH>0<CR>

Positive response.

The controller will respond with ACK for compatibility with older controllers. This

format is the only format supported by this controller.

Description:

Sends a continuous stream of X/Y coordinate data when you touch the sensor. The

controller continues to send data as long as you touch the sensor. The controller sends the

data even if the touch is stationary and unchanging.