mpr081 Freescale Semiconductor, Inc, mpr081 Datasheet - Page 6

• Manufacturer Part Number: mpr081
• Description: Touch Pad Controller
• Manufacturer: Freescale Semiconductor, Inc

Table 7. MPR08 Family Overview
MPR081
6
FUNCTIONAL OVERVIEW
combinations of capacitive touch pads, capacitive sliders,
capacitive rotaries, and mechanical keys. The device
includes a piezo buzzer driver which generates key click
sounds to provide audible feedback of pad touches and/or
A quick word on terminology:
– A mechanical keyswitch is a switch containing, at its
– A capacitive touch pad is a contactless 'key' which
– A capacitive rotary is a group of touch pads arranged in
– A capacitive slider is an elongated touch pad for which
– A full pad is a touch pad whose conductive area is
MPR081
MPR082
1. The 20 pads are implemented by two independent arrays of 10 touch pads.
The MPR081user interface controller monitors various
Product
simplest, two contacts which have either a high (>10 M:)
or a low resistance (<10 k:) between them depending on
switch position. Momentary push switches normally are
low resistance when pressed. Latching switches (such as
slide switches) provide high resistance in one position,
low resistance in the other.
detects the presence or absence of a finger. The raw
detection output is a single bit giving touch condition.
a ring for which not only the presence or absence of a
finger is detected, but also the position of a finger along
the circumference of the rotary.
not only the presence or absence of a finger is detected,
but also the position of a finger along the length of the
slider. The raw detection output is a single bit giving touch
condition, plus a multi-bit word for position. A typical
application is a volume control, where one end of the
slider corresponds to minimum volume and the other end
to maximum.
connected to one electrode of the touch controller and
ground.
I
I
2
2
C with RST
C with RST
Bus
Sounder
Yes
Yes
DETAILED DESCRIPTION
Rotary Slider
16-Positions
—
key presses. The MPR081 also uses a standardized user
register set to configure the part on power up, and to read
pad, slider and key status. The commonality between
products in the MPR08 family of controllers simplifies
migration between parts.
– A split pad is a touch pad whose conductive area is
– A pad array is a collection of full and split pads
– A pad array with n key lockout will only report one touch
– A pad array with 2 key rollover ignores further pads after
–
Touch Pad Array
connected to more than one electrode of the touch
controller. For the MPR08 family, a split pad is always
connected to two electrodes and typically looks like a pair
of interlaced fingers.
interconnected to each other and a number of electrode
lines. The number of pads available in a pad array with N
electrode lines using full and two-electrode split pads is
sum(1 to N), made up of N full pads and sum(1 to (N-1))
split pads. The MPR082 uses two sets of 4 electrode lines
and, therefore, each 4-electrode pad array has a
capability of 4 full pads and sum(1 to 3) or 1+2+3 = 6 split
pads, and a total pad count of sum(1 to 4) or 1+2+3+4 =
10 full plus split pads.
at a time. Multiple simultaneous touches are ignored.
touching a first pad. If a pad is touched and held, and then
a second pad is touched, the second pad is ignored. If the
first pad is released while the second pad is still touched,
then the second pad will be reported as a new touch.
pads will be detected as pressed in succession or
simultaneously without requiring any previous pads to be
released first.
A pad array with n-key rollover allows any number of
20 Pads
—
(1)
Highest resolution rotary
Two independent arrays of 10 touch pads
Freescale Semiconductor
Main Attribute
Sensors