Glossary
AN66308 - CY8CMBR2044 CapSense® Design Guide, Doc. No. 001-66308 Rev. *F
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CapSense Sigma Delta (CSD) is a Cypress-patented method of performing self-capacitance (also called
self-cap) measurements for capacitive sensing applications.
In CSD mode, the sensing system measures the self-capacitance of an electrode, and a change in the
self-capacitance is detected to identify the presence or absence of a finger.
Debounce
A parameter that defines the number of consecutive scan samples for which the touch should be present
for it to become valid. This parameter helps to reject spurious touch signals.
A finger touch is reported only if the Difference Count is greater than Finger Thr Hysteresis for a
consecutive Debounce number of scan samples.
Driven-Shield
A technique used by CSD for enabling liquid tolerance in which the Shield Electrode is driven by a signal
that is equal to the sensor switching signal in phase and amplitude.
Electrode
A conductive material such as a pad or a layer on PCB, ITO, or FPCB. The electrode is connected to a
port pin on a CapSense device and is used as a CapSense sensor or to drive specific signals associated
with CapSense functionality.
Finger Threshold
A parameter used with Hysteresis to determine the state of the sensor. Sensor state is reported ON if the
Difference Count is higher than Finger Threshold + Hysteresis, and it is reported OFF if the Difference
Count is below Finger Threshold
– Hysteresis.
Ganged Sensors
The method of connecting multiple sensors together and scanning them as a single sensor. Used for
increasing the sensor area for proximity sensing and to reduce power consumption.
To reduce power when the system is in low-power mode, all the sensors can be ganged together and
scanned as a single sensor taking less time instead of scanning all the sensors individually. When the
user touches any of the sensors, the system can transition into active mode where it scans all the sensors
individually to detect which sensor is activated.
PSoC supports sensor-ganging in firmware, that is, multiple sensors can be connected simultaneously to
AMUXBUS for scanning.
Gesture
Gesture is an action, such as swiping and pinch-zoom, performed by the user. CapSense has a gesture
detection feature that identifies the different gestures based on predefined touch patterns. In the
CapSense component, the Gesture feature is supported only by the Touchpad Widget.
Guard Sensor
Copper trace that surrounds all the sensors on the PCB, similar to a button sensor and is used to detect a
liquid stream. When the Guard Sensor is triggered, firmware can disable scanning of all other sensors to
prevent false touches.
Hatch Fill or Hatch Ground or Hatched Ground
