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Several questions for turning LEDs on with PCA9956B

Question asked by daehyeon kim on Apr 13, 2017
Latest reply on May 2, 2017 by Dario Arias



I'm using PCA9956B to controll 40pcs of RGB LEDs

I connect 5 of PCA9956B and gave the address(10h, 12h, 14h, 16h, 18h) to them.

then, 8 RGB LEDs is to be connected to each PCA9956B

(because PCA9956B is 24-channel controller, RGB LED has 3-pin)


When I send I2C messages to each addresses I can see the ACK signal on the I2C lines.

So I've tried to turn LEDs on, but it doesn't seem to be working well.


The first thing I've done is that pulling down the /OE pin to ground.

on the datasheet, It is nessesary to make LEDs turning on

then Initialized MODE1 register as default values for unexcepted situations

and change the registers such as LEDOUT, PWM, IREF..


But I can't see any LED lighting.

What I have to check or do I miss something to do here?


Thank for your assistance.