SX8663 datasheet(21/64 Pages) SEMTECH

21 / 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

3.13 Interrupt

3.13.1 Power up

During power up the INTB is kept low. Once the power up sequence is terminated the INTB is cleared

autonomously. The SX8663 is then ready for operation.

Figure 17

Power Up vs. INTB

During the power on period the SX8663 stabilizes the internal regulators, RC clocks and the firmware initializes all

registers.

During the power up the SX8663 is not accessible and I2C communications are forbidden. The GPIOs set as

inputs with a pull up resistor.

As soon as the INTB rises the SX8663 will be ready for I2C communication. The GPIOs are then configured

according the parameters in the SPM.

The value of INTB before power up depends on the INTB pull up resistor supply voltage.

3.13.2 Assertion

INTB is updated in Active or Doze mode once every scan period.

The INTB will be asserted at the following events:

• if a Button event occurred (touch or release if enabled). I2C register CapStatKeys show the detailed status of

the Buttons,

• when actually entering Active or Doze mode via a host request (may be delayed by 1 scan period). I2C

• once compensation procedure is completed either through automatic trigger or via host request (may be

delayed by 1 scan period),

• once SPM write is effective (may be delayed by 1 scan period),

• once NVM burn procedure is completed (may be delayed by 1 scan period),

• during reset (power up, hardware RESETB, software reset).

3.13.3 Clearing

The clearing of the INTB is done as soon as the host performs a read to any of the SX8663 I2C registers.

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