PCA9552_06 datasheet(9/28 Pages) PHILIPS

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PCA9552_5

Product data sheet

Rev. 05 — 9 March 2006

9 of 28

Philips Semiconductors

PCA9552

16-bit I2C-bus LED driver with programmable blink rates

6.4 Pins used as GPIOs

LED pins not used to control LEDs can be used as general purpose I/Os (GPIOs).

For use as input, set LEDn to high-impedance (01) and then read the pin state via the

input register.

For use as output, connect external pull-up resistor to the pin and size it according to the

DC recommended operating characteristics. LED output pin is HIGH when the output is

programmed as high-impedance, and LOW when the output is programmed LOW through

the ‘LED selector’ register. The output can be pulse-width controlled when PWM0 or

PWM1 are used.

6.5 Power-on reset

When power is applied to VDD, an internal Power-On Reset (POR) holds the PCA9552 in

a reset condition until VDD has reached VPOR. At that point, the reset condition is released

and the PCA9552 registers are initialized to their default states. Thereafter, VDD must be

lowered below 0.2 V to reset the device.

6.6 External RESET

A reset can be accomplished by holding the RESET pin LOW for a minimum of tw(rst). The

PCA9552 registers and I2C-bus state machine will be held in their default states until the

RESET input is once again HIGH.

This input requires a pull-up resistor to VDD if no active connection is used.

PCA9552 Datasheet(PDF) 9 Page - NXP Semiconductors