SX8661 datasheet(30/88 Pages) SEMTECH

30 / 88 page

ADVANCED COMMUNICATIONS & SENSING

DATASHEET

Revision v3.2, January 2011

www.semtech.com

SX8661

Low Power, Capacitive Button Touch and Proximity Controller

(8 sensors) with LED Drivers and Analog Output

3.18 General Purpose Input and Outputs

The SX8661 offers eight General Purpose Input and Outputs (GPIO) pins which can be configured in any of these

modes:

- GPP (General Purpose PWM)

- GPO (General Purpose Output)

- SPO (Special Purpose Output)

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 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.

Figure 28

polarity = 1 (a), polarity = 0 (b)

The PWM blocks used in GPP and 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 29

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

3.18.1 GPP mode

GPIOs configured as GPP will operate as PWM outputs directly controlled by the host. A typical application is

LED dimming.

Typical GPP operation is illustrated in figure below.

SX8661 데이터시트(PDF) 30 Page - Semtech Corporation