3M™ MicroTouch™ Controller SX112 Reference Guide
21
3M Touch Systems, Inc. Proprietary Information
Table 7 Calibrate Raw 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.
Diagnostic Command
Syntax:
<SOH>
DX
<CR>
Description:
This command requests that the controller check for sensor failures such as broken
corners, broken wires, etc.
Response:
<SOH>
0
<CR> Positive
response.
<SOH>
1
<CR>
Command not supported.
<SOH>
2
<CR> Failure
detected.
Finger Only
Syntax:
<SOH>
FO
<CR>
Description:
The controller is set to only respond to finger touches and disable the pen.
Response:
<SOH>
0
<CR> Positive response
Format Raw
Syntax:
<SOH>
FR
<CR>
Description:
Returns the signal level (amount of touch) of each of the four sensor corners in digital
format. The returned values are not corrected for stray values.
The Format Raw data is a 41-byte packet that includes 1 status byte and 40 bytes of
binary corner data. The first byte of each packet always has its high bit (Bit 7) set to
provide synchronization with the host system. Refer to Table 8 for General Packet
Formats. Each corner data is composed of a pair of 32-bit I and Q values, which are
delivered in 10 bytes.
I and Q are complex touch currents as measured in phase and 90 degrees out of phase
with the corner drive signal. Refer to Table 9 for I/Q Corner Components.
To use the Format Raw command, the controller and host system must be in an 8-bit data
communication mode. The Format Raw command returns a negative response if the
controller is not using an 8-bit communication mode.
