Atmel ARM-Based Evaluation Kit AT91SAM9N12-EK AT91SAM9N12-EK Scheda Tecnica
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AT91SAM9N12-EK
873
SAM9N12/SAM9CN11/SAM9CN12 [DATASHEET]
11063K–ATARM–05-Nov-13
Figure 42-9. 5-Wire principle
42.7.6 5-wire Position Measurement Method
In an application only monitoring clicks, 100 points per second is typically needed. For handwriting or motion detection,
the number of measurements to consider is approximately 200 points per second. This must take into account that
multiple measurements are included (over sampling, filtering) to compute the correct point.
the number of measurements to consider is approximately 200 points per second. This must take into account that
multiple measurements are included (over sampling, filtering) to compute the correct point.
The 5-wire touchscreen panel works by applying a voltage at the corners of the resistive layer and measuring the vertical
or horizontal resistive network with the sense input. The ADC converts the voltage measured at the point the panel is
touched.
or horizontal resistive network with the sense input. The ADC converts the voltage measured at the point the panel is
touched.
A measurement of the Y position of the pointing device is made by:
Connecting Upper left (UL) and upper right (UR) corners to VDDANA
Connecting Lower left (LL) and lower right (LR) corners to ground.
The voltage measured is determined by the voltage divider developed at the point of touch (Yposition) and the
SENSE input is converted by ADC.
SENSE input is converted by ADC.
A measurement of the X position of the pointing device is made by:
Connecting the upper left (UL) and lower left (LL) corners to ground
Connecting the upper right and lower right corners to VDDANA.
The voltage measured is determined by the voltage divider developed at the point of touch (Xposition) and the
SENSE input is converted by ADC.
SENSE input is converted by ADC.
Pen
Contact
U
L
U
R
L
L
L
R
Sense
Resistive layer
Conductive Layer
U
L
U
R
L
L
L
R
VDDANA
GND
VDDANA for Yp
GND for Xp
VDDANA for Xp
GND for Yp
Sense