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Blinking across multiple PCA9745B LED drivers

Question asked by Oliver Ebert on Jan 16, 2018
Latest reply on Jan 17, 2018 by Oliver Ebert

Hello,

 

we're using two (SPI-)daisy-chained NXP PCA9745B LED drivers and want to blink some LEDs synchronously on both ICs.  The respective LEDs of each driver are associated with a LED group that is configured identically on both ICs.  The gradation start command is issued simultaneously to both ICs.  While the LEDs on each IC are blinking in sync (as expected), the blinking frequencies between different ICs seem to differ and the blinking LEDs diverge pretty quickly!  I don't see any facilities for synchronizing multiple drivers (except for using the /OE pin for external dimming/blinking?)... am I missing something?  Is this use case even supported by the drivers?

 

How would one go about blinking LEDs synchronously across multiple PCA9745B LED drivers?

 

Thanks and regards

Oliver

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