User guide

CY3280-MBR3 Evaluation Kit User Guide, Doc. #: 001-89905 Rev. *B 46
Hardware
Figure 4-16. Default J15
Note: The kit is shipped with the combination/setting 'C' and the third jumper is connected vertically
so that it is not shorted to any other pin.
4.3.7 Capacitance Variation Demonstration
The kit provides three methods to demonstrate parasitic capacitance variation on the button sensors
available on the kit, as shown in Figure 4-17. These methods are used to showcase the SmartSense
auto-tuning capability of the device. See SmartSense Auto-Tuning Feature on page 28 to learn the
procedure to test these methods using this kit.
The methods are:
■ Using the trace method: Button BTN4 (connected to the CS6 pin of CY8CMBR3116) is con-
nected to the SW3 slide switch, which can be used to provide two different routes between the
pin and the sensor pad. One route is longer than the other. Different trace lengths have different
parasitic capacitance; therefore, you can change the length of the trace to change the parasitic
capacitance on the sensor.
■ Using external capacitance: The SW1 switch is provided to add an extra capacitance of 10 pF or
15 pF on BTN2 (connected to the CS4 pin of the CY8CMBR3116).
■ Using an additional 1-mm overlay: An additional overlay of 1 mm is provided with this kit. You can
place this overlay over the sensors to change the parasitic capacitance.