PCA9552

     The PCA9552 LED Blinker blinks LEDs in I² C-bus and SMBus applications where PCA9552 is necessary to limit bus traffic or free up the I²C Master!fls (MCU, MPU, DSP, chipset, etc.) timer. The uniquenes of PCA9552 is the internal oscillator with two programmable blink rates. To blink LEDs using normal I/O Expanders like the PCF8574 or PCA9554, the bus master must send repeated commands to turn the LED on and off. PCA9552  greatly increases the amount of traffic on the I²C-bus and uses up one of the mastertimers.

   The PCA955 LED Blinker instead requires only the initial set up command to program BLINK RATE 1 and BLINK RATE 2 (i.e., the frequency and duty cycle) for each individual output. From then on, only one command from the bus master is required to turn each individual open drain output ON, OFF, or to cycle at BLINK RATE 1 or BLINK RATE 2. Maximum output sink current is 25 mA per bit and 200 mA per package.