sx8638 Semtech Corporation, sx8638 Datasheet - Page 25

• Manufacturer Part Number: sx8638
• Description: Low Power, Capacitive Button And Slider Touch Controller 8 Sensors With Enhanced Led Drivers And Proximity
• Manufacturer: Semtech Corporation

SX8638
Low Power, Capacitive Button and Slider Touch Controller
(8 sensors) with Enhanced LED Drivers and Proximity
ADVANCED COMMUNICATIONS & SENSING
DATASHEET
3.15.4 Example
A typical example of the assertion and clearing of the INTB and the I2C communication is shown in Figure 25.
Interrupt and I2C
Figure 25
When a button is touched the SX8638 will assert the interrupt (1). The host will read the IrqSrc information over
the I2C and this clears the interrupt (2).
If the finger releases the button the interrupt will be asserted (3). The host reading the IrqSrc information will clear
the interrupt (4).
In case the host does not react to an interrupt this results in a missing touch.
3.16 General Purpose Input and Outputs
3.16.1 Introduction and Definitions
The SX8638 offers eight General Purpose Input and Outputs (GPIO) pins which can be configured in any of these
modes:
- GPI (General Purpose Input)
- GPP (General Purpose PWM)
- GPO (General Purpose Output)
Each of these modes is described in more details in the following sections.
The polarity of the GPP and GPO pins is defined as in figure below, driving an LED as example. It has to be set
accordingly in SPM parameter GpioPolarity.
Polarity definition, (a) normal, (b) inverted
Figure 26
Revision 7_6, September 10
© 2010 Semtech Corp.
www.semtech.com
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