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Dotstar LED - How does it work?
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Dotstar LED - How does it work?

by momo1 on Fri Apr 23, 2021 6:16 am

Hi there,

I was looking at the Dotstar LED strip and could not fully understand how it communicates with the LEDs and the accompanying microcontrollers attached to them. I know that it uses SPI protocol to send a 32 Byte message to the LEDs to let them know what colour to display. But I'm confused how this communication takes place. My understanding of the SPI protocol is that it is a synchronous protocol that reads data on each clock cycle. However, how do the LEDs know that a message is for them instead of some other LED. If we are providing a serial input signal, how it that propensated down the strip of LEDs and how come an LED can know that it should turn on rather than the other LEDs near it?

momo1
 
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Re: Dotstar LED - How does it work?

by adafruit_support_bill on Fri Apr 23, 2021 7:07 am

The microcontroller sends a series of bytes to the pixels strip. The first pixel will keep the first 3 bytes it receives (4 bytes for RGBW) and pass the rest along to the next pixel in the chain.

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Please be positive and constructive with your questions and comments.