Datasheet

AR1000 SERIES RESISTIVE TOUCH SCREEN CONTROLLER
DS41393B-page 12 Preliminary  2009-2012 Microchip Technology Inc.
3.2 4, 5, 8-Wire Sensor Selection
The desired sensor type of 4/8-wire or 5-wire is
hardware selectable using pin M2.
If 4/8-wire has been hardware-selected, then the
choice of 4-wire or 8-wire is software-selectable via the
TouchOptions Configuration register.
When 4/8-wire is hardware-selected, the controller
defaults to 4-wire operation. If 8-wire operation is
desired, then the TouchOptions Configuration register
must be changed.
3.3 4-Wire Touch Sensor Interface
Sensor tail pinouts can vary by manufacturer and part
number. Ensure that both sensor tail pins for one
sensor axis (layer) are connected to the controller’s
X-/X+ pins and the tail pins for the other sensor axis
(layer) are connected to the controller’s Y-/Y+ pins. The
controller’s X-/X+ and Y-/Y+ pin pairs do not need to
connect to a specific sensor axis. The orientation of
controller pins X- and X+ to the two sides of a given
sensor axis is not important. Likewise, the orientation of
controller pins Y- and Y+ to the two sides of the other
sensor axis is not important.
Connections to a 4-wire touch sensor are as follows
(See Figure 3-2).
FIGURE 3-2: 4-WIRE TOUCH SENSOR INTERFACE
Tie unused controller pins 5WSX-, SX+, SY-, and SY+
to V
SS.
See Section 3.8 “ESD Considerations” and
Section 3.9 “Noise Considerations” for important
information regarding the capacitance of the controller
schematic hardware.
TABLE 3-1: 4/8-WIRE vs. 5-WIRE
SELECTION
Type M2 pin
4/8-wire V
SS
5-wire VDD