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EX II 3000SP Controller Reference Guide
3M Touch Systems Proprietary Information
Format Tablet
Syntax: <SOH>FT<CR>
Description: Outputs the X/Y touch coordinate data in a 5-byte packet. The packet
includes 1 status byte and 4 bytes of binary X/Y coordinate data. The
protocol also establishes the X and Y coordinate output as 14 binary bits
providing a range of 0 to 16,383.
The low order bits (X3 – X0 and Y3 – Y0) are not significant in a 1024 by
1024 touch screen because data can fluctuate with each touch, and therefore
may not be completely accurate.
To use Format Tablet, the controller and host system must be in an 8-bit
data communication mode. The Format Tablet command returns a negative
response if the controller is in 7-bit format.
Response:
<SOH>0<CR> Positive response
After the controller is in Format Tablet mode, touching the screen causes
the controller to return a response in the following format:
SXxYy
S = Status byte, first byte of data. Refer to Table 8.
Xx = X (horizontal) coordinate data; second and third bytes of data.
Yy = Y (vertical) coordinate data; fourth and fifth bytes of data.
Table 8 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
*MSB = Most Significant Bit, LSB = Least Significant Bit
Table 9 defines the status bits (Byte 1) for the Format Tablet data.