sx8645 Semtech Corporation, sx8645 Datasheet - Page 25

• Manufacturer Part Number: sx8645
• Description: Ultra Low Power, Capacitive Button And Wheel Touch Controller 12 Sensors With Enhanced Led Drivers
• Manufacturer: Semtech Corporation

ADVANCED COMMUNICATIONS & SENSING
3.15.4 Example
A typical example of the assertion and clearing of the INTB and the I2C communication is shown in Figure 25.
When a button is touched the SX8645 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 SX8645 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.
Revision 7_5, February 10
Figure 26
Polarity definition, (a) normal, (b) inverted
Touch Controller (12 sensors) with Enhanced LED Drivers
Figure 25
© 2010 Semtech Corp.
Interrupt and I2C
25
Ultra Low Power, Capacitive Button and Wheel
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SX8645