MPR084

Sensors

4

Freescale Semiconductor

Preliminary

2

External Signal Description

2.1

Device Pin Assignment

Table 3 shows the pin assignment for the MPR084. For a more detailed description of the functionality of each pin, refer to the

appropriate chapter.

The two packages available for the MPR084 are a 5x5mm 16 pin QFN and a 4x5mm 16 pin TSSOP. Both of the packages and

their respective pinouts are shown in Figure 3.

Figure 3. Package Pinouts

2.2

Recommended System Connections

The MPR084 Capacitive Touch Sensor Controller requires ten external passive components. When connecting the MPR084 in

a touch sensor system, the electrode lines must have pull-up resistors. The recommended value for these pull-ups is 780k

Ω.

Some electrode arrays will require higher or lower values depending on the application.

In addition to the 8 resistors a bypass capacitor of 1µF should always be used between the VDD and VSS lines.and a 4.7

Ωk

pull-up resistor should be included on the IRQ.

Table 3. Device Pin Assignment

Pin

Name

Function

1ATTN

Attention Pin. Input, active low, when asserted sets the Configuration Register’s DCE bit high

allowing communication with the part.

2IRQ

Interrupt Request Pin. Output, active-low, open-drain interrupt request signaling new events.

3

VDD

Positive Supply Voltage

4

VSS

Ground

5SCL

6SDA

7

AD0

Address input. Low = slave address 0x5C. High = slave address 0x5D.

8

SOUNDER

Sounder driver output. Connect a piezo sounder from this output to ground. Output is push-pull

9 - 16

E1, E2, E3, E4, E5,

E6, E7, E8

Touch Pad Electrode connections.

PAD

Exposed pad

Exposed pad on package underside (QFN only). Connect to VSS.

E5

E6

E7

E8

VDD

VSS

ATTN

IRQ

3

4

1

2

10

9

12

11

78

56

14 13

16 15

E1

E2

E3

E4

E5

E6

E7

E8

VDD

VSS

SCL

SDA

AD0

SOUNDER

ATTN

IRQ

1

4

3

2

5

8

7

6

16

13

14

15

12

9

10

11

QFN

TSSOP