MPR083

Sensors

Freescale Semiconductor

3

Preliminary

1.1.3

Terminology

The following terms are used to describe front panel interface and capacitive touch sensor technology throughout this document.

Table 2. Terminology

Term

Definition

Touch Sensor

A Touch Sensor is the combination of a Touch Sensor Controller and a connected conductive area

referred to as an electrode.

Touch Sensor Controller

A Touch Sensor Controller is the intelligent part of a Touch Sensor which measures capacitance and

differentiates between touched and untouched pads.

Key

A Key or Switch is a mechanical device that makes an electrical connection only when pressed.

Touch Pad

A Touch Pad is a type of capacitive sensor that is used for direct replacement of a Key. A capacitive

touch sensor determines touch state by differentiating between high and low capacitances. When

there is a change in the state this can be interpreted in the same way as a mechanical Key.

Encoder

An Encoder is a group of touch pads arranged in a circular shape where the state of each touch pad

is used to determine the direction of rotation around the touch pads.

Rotary

A Rotary is a group of touch pads arranged in a circular shape where the state of each touch pad is

interpreted as an angle along the touch pads.

Slider

A Slider is a group of touch pads arranged in a row where the state of each touch pad is used to

determine the position along the length of the touch pads.

Solid Pad

A Solid or Full Pad is a type of touch pad where exactly one electrode is used

Split Pad

A Split Pad is a type of touch pad where more than one electrode is used. Split Pads are used to

increase the total number of possible touch pads without increasing the electrical connections to the

Touch Sensor Controller.

N-key Lockout

N-Key Lockout refers to the logic that determines how many keys can be simultaneously touched in

a system. For example, 1-key lockout would only allow a single key to be touched before ignoring

all future touches.

N-key rollover

N-Key Rollover refers to the logic that determines how many keys can be pressed in succession

without releasing previous keys. For example, a system with 1-key lockout and 2-key rollover would

allow 2-keys to be pressed in succession but would only report the second key once the first key

was released.

Inter-Integrated Circuit Communication