low level spi control for dotstar

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lobsterman
 
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Joined: Fri Mar 10, 2017 12:56 pm

low level spi control for dotstar

Post by lobsterman »

Hi all, I am trying to control a single dotstar LED with my low level control tools. i am quite familiar with I2C (via SDA, SCL Pins), but the Dotstar needs to be driven with SPI which in my hands is a 4 wire interface (MOSI, MISO, SCK, CS). The Adafruit description talks about a 2 wire control <https://learn.adafruit.com/adafruit-dotstar-leds> labeled data D0 and clock C0 and I am trying to match up how the C1/D1 maps onto my standard SPI pins MOSI/MISO/SCK/CS. Is MOSI = D1? Is SCK = C1? I am controlling the interface from an FTDI click <http://pub.ucpros.com/download/ftdi_cli ... qs2h4cm8t4> using my serial java libraries and any advice on the fundamental mechanics for how the Adafruit/Dotstar terminology matches up with standard SPI terminology would be greatly appreciated. Best,

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coyote20000
 
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Re: low level spi control for dotstar

Post by coyote20000 »

Hey there,
I think the icsp pins would work without issue.

Mosi would be your data pin and CLK would be your clock. MISO is not needed because the led really has nothing to say back to the uC. (One way communication).

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adafruit_support_carter
 
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Re: low level spi control for dotstar

Post by adafruit_support_carter »

MOSI -> DI
SCK -> CI

MISO isn't used since the LEDs do not return any data. CS isn't used in the case of DotStars.

You want to use the I pins (DI/CI) instead of the O pins (DO/CO). The I pins are the input to the chain, the O pins are the output of the chain.

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