MPR121_10 FREESCALE [Freescale Semiconductor, Inc], MPR121_10 Datasheet - Page 43

• Manufacturer Part Number: MPR121_10
• Description: Proximity Capactive touch Senosr controller
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

Sensors
Freescale Semiconductor
AN3894: MPR121 GPIO and LED Driver Function
INTRODUCTION
vice. MPR121 not only has priority unique features like independent electrode auto configuration (refer to AN3889), 13th simu-
lated pseudo electrode for proximity detection (refer to AN3893), it also has 8 GPIO ports with LED driver capability. The GPIO
and LED driver function can be used when not all the 12 input sensing channels are occupied for touch sensing detection, which
is made possible by internal multiplexed pin structure. This increaseS the cost efficiency of the system and makes the MPR121
fit for even wider application.
MULTIFUNCTION PINS
tifunction pins. When these multifunction pins are not configured as electrodes, they may be used to drive LED or for general
GPIO purpose.
PIN #
ELECTRODE
GPIO
MPR121 is a feature rich second generation touch sensor controller after Freescale’s initial release of the MPR03x series de-
MPR121 has 12 input sensing channels ELE0~ELE11, which occupies pin 8 to pin 19. Among these, pin 12 to pin 19 are mul-
ELE0
—
8
Figure 46. Configuration 1: MPR121 runs from a 1.71 V to 2.75 V supply.
1.71 V to 2.75 V
ELE1
—
9
VDD
ELE2
10
—
GND
ELE3
11
—
0.1 μF
1.71 V to 2.75 V
GPIO0
ELE4
12
VDD
GND
75 kΩ 1%
GPIO1
ELE5
13
20
6
5
1
2
3
4
7
VDD
VSS
VREG
IRQ
SCL
SDA
ADDR
REXT
GPIO2
ELE6
14
TOUCH SENSOR
MPR121Q
GPIO3
ELE7
15
ELE11/LED7
ELE10/LED6
ELE9/LED5
ELE8/LED4
ELE7/LED3
ELE6/LED2
ELE5/LED1
ELE4/LED0
GPIO4
ELE8
ELE3
ELE2
ELE1
ELE0
16
19
18
17
16
15
14
13
12
11
10
9
8
GPIO5
ELE9
17
GPIO6
ELE10
18
MPR121
ELE11
GPIO7
19
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