SX8663 datasheet(24/64 Pages) SEMTECH

24 / 64 page

ADVANCED COMMUNICATIONS & SENSING

Rev5 4

th August 2011

www.semtech.com

SX8663

Capacitive Button Matrix (up to 36) and Proximity Controller

with Individual LED Drivers and Buzzer Output

3.15 General Purpose Input and Outputs

The SX8663 offers eight General Purpose Input and Outputs (GPIO) pins which can be configured in any of these

modes:

- GPO (General Purpose Output) with Autoligth ON/OFF

- SPO (Special Purpose Output). GPIO7 only; in this mode the GPIO can be connected to an external buzzer.

The input state of the GPIO is only used during the initial phase of the power up period.

Each of these GPIO modes is described in more details in the following sections.

The polarity of the GPO pins is defined as in figure below, driving an LED as example. It has to be set accordingly

in SPM parameter GpioPolarity.

Figure 22

polarity = 1/Normal (a), polarity = 0/Inverted (b)

The PWM blocks used GPO modes are 8-bits based and clocked at 2MHz typ. hence offering 256 selectable

pulse width values with a granularity of 0.5us typ.

Figure 23

PWM definition, (a) small pulse width, (b) large pulse width

3.15.1 GPO

GPIOs configured as GPO will operate as digital outputs which can generate both standard low/high logic levels

and PWM low/high duty cycles levels. Typical application is LED ON/OFF control.

Transitions between ON and OFF states can be triggered either automatically (Autolight ON) or manually by the

host (Autolight OFF). This is illustrated in figures below.

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