New family of LED dimmers and blinkers expands use of the IІC Bus in computing, communication and networking applications
October 6, 2003 - Royal Philips Electronics announced two new series of IІC General Purpose I/O expanders (PCA953x and PCA955x) optimized for controlling LED dimming and blinking in products ranging from mobile phones to servers in computing, communication and networking applications. These new 2, 4, 8 and 16 bit devices represent an innovation in IІC capabilities, allowing designers an easier way to build systems with more dimming or blinking LEDs than previously possible using just basic General Purpose I/Os (GPIO) or microcontrollers (MCUs).Manufacturers of applications such as cell phones and servers are increasingly requiring multiple blinking LEDs for eye-catching keypad lighting applications, as well as practical purposes such as status indication. The new PCA953x LED Dimmers and PCA955x LED Blinkers allow more system flexibility by off-loading the LED power consumption and eliminating the programming of the MCU.
The new IІC devices have an internal oscillator with four 8-bit (256 values) internal registers that are used to set two programmable blink rates. This removes the need for the MCU to use one of its timers to send repeated commands to "blink" LEDs (repeatedly turning individual LEDs on and off). It also significantly reduces the IІC bus traffic compared to when a standard GPIO is used to blink or dim the LED freeing up the IІC bus for additional traffic and control of additional devices. Once programmed, the internal oscillator allows the IІC bus to be disconnected from the PCA953x or PCA955x with the LED continuing to be dimmed or blink, something not possible with normal GPIOs.
Availability
The 8-pin PCA9550 2-bit LED Blinker, 16-pin PCA9551 8-bit LED Blinker, 24-pin PCA9552 16-bit LED Blinker/PCA9532 16-bit LED Dimmer and 8-pin PCA9553 4-bit LED Blinker are available now. The 8-pin PCA9530 2-bit LED Dimmer, 16-pin PCA9531 8-bit LED Dimmer and 8-pin PCA9533 4-bit LED Dimmer are sampling now with releases through the end of the year.
