48 lines
1.9 KiB
Markdown
48 lines
1.9 KiB
Markdown
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# APA102 Module
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| Since | Origin / Contributor | Maintainer | Source |
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| :----- | :-------------------- | :---------- | :------ |
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| 2016-01-26 | [Robert Foss](https://github.com/robertfoss)| [Robert Foss](https://github.com/robertfoss)| [apa102.c](../../app/modules/apa102.c)|
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This module provides Lua access to [APA102 RGB LEDs](https://youtu.be/UYvC-hukz-0) which are similar in function to the common [WS2812](ws2812) addressable LEDs.
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> DotStar LEDs are 5050-sized LEDs with an embedded micro controller inside the LED. You can set the color/brightness of each LED to 24-bit color (8 bits each red green and blue). Each LED acts like a shift register, reading incoming color data on the input pins, and then shifting the previous color data out on the output pin. By sending a long string of data, you can control an infinite number of LEDs, just tack on more or cut off unwanted LEDs at the end.
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source: [Adafruit](https://www.adafruit.com/products/2343)
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## apa102.write()
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Send ABGR data in 8 bits to a APA102 chain.
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#### Syntax
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`apa102.write(data_pin, clock_pin, string)`
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#### Parameters
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- `data_pin` any GPIO pin 0, 1, 2, ...
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- `clock_pin` any GPIO pin 0, 1, 2, ...
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- `string` payload to be sent to one or more APA102 LEDs.
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It should be composed from a ABGR quadruplet per element.
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- `A1` the first pixel's Intensity channel (0-31)
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- `B1` the first pixel's Blue channel (0-255)<br />
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- `G1` the first pixel's Green channel (0-255)
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- `R1` the first pixel's Red channel (0-255)
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... You can connect a lot of APA102 ...
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- `A2`, `B2`, `G2`, `R2` are the next APA102s Intensity, Blue, Green and Red channel parameters
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#### Returns
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`nil`
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#### Example 1
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```lua
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a = 31
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b = 0
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g = 0
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r = 255
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leds_abgr = string.char(a, b, g, r, a, b, g, r)
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apa102.write(2, 3, leds_abgr) -- turn two APA102s to red, connected to data_pin 2 and clock_pin 3
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```
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#### Example 2
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```lua
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-- set the first 30 leds to red
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apa102.write(2, 3, string.char(31, 255, 0, 0):rep(30))
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```
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