The Plasma library is intended to drive APA102 / DotStar™ or WS2812 / NeoPixel™ LEDs on the Plasma 2040 board, though it can be used with your own custom pins/wiring.
- [Notes On PIO Limitations](#notes-on-pio-limitations)
The WS2812 and APA102 drivers use the PIO hardware on the RP2040. There are only two PIOs with four state machines each, placing a hard limit on how many separate LED strips you can drive.
In most cases you'll use `0` for PIO and `0` for PIO state-machine, but you should change these if you plan on running different strand types together, or if you're using something else that uses PIO.
Construct a new `WS2812` instance, specifying the number of LEDs, PIO, PIO state-machine and GPIO pin.
```python
import plasma
LEDS = 30
FPS = 60
led_strip = plasma.WS2812(LEDS, 0, 0, 15)
```
Start the LED strip by calling `start`. This sets up a timer which tells the RP2040 to DMA the pixel data into the PIO (a fast, asyncronous memory->peripheral copy) at the specified framerate.
You can set the colour of an LED in either the RGB colourspace, or HSV (Hue, Saturation, Value). HSV is useful for creating rainbow patterns.
#### RGB
Set the first LED - `0` - to Purple `255, 0, 255`:
```python
led_strip.set_led(0, 255, 0, 255)
```
#### HSV
Set the first LED - `0` - to Red `0.0`:
```python
led_strip.set_hsv(0, 0.0, 1.0, 1.0)
```
### Set Brightness
APA102 pixels support global brightness, allowing their brightness to be specified independent of their colour. You can set the overall brightness of your strip by calling:
```python
led_strip.set_brightness(15)
```
You can set brightness from `0` to `31`. This directly maps to the 5-bit brightness value sent to the APA102 LEDs.
Construct a new `APA102` instance, specifying the number of LEDs, PIO, PIO state-machine and GPIO data/clock pins.
```python
import plasma
LEDS = 30
FPS = 60
led_strip = plasma.APA102(LEDS, 0, 0, 15, 14)
```
Start the LED strip by calling `start`. This sets up a timer which tells the RP2040 to DMA the pixel data into the PIO (a fast, asyncronous memory->peripheral copy) at the specified framerate.
```python
led_strip.start(FPS)
```
### Set An LED
You can set the colour of an LED in either the RGB colourspace, or HSV (Hue, Saturation, Value). HSV is useful for creating rainbow patterns.
#### RGB
Set the first LED - `0` - to Purple `255, 0, 255`:
The `plasma` module contains constants for the LED and button pins:
*`plasma.PIN_LED_R` = 16
*`plasma.PIN_LED_G` = 17
*`plasma.PIN_LED_B` = 18
*`plasma.PIN_BUTTON_A` = 12
*`plasma.PIN_BUTTON_B` = 13
### Buttons
Import the `Button` class from the `pimoroni` module and the pin constants for the buttons:
```python
from pimoroni import Button
from plasma import PIN_BUTTON_A, PIN_BUTTON_B
```
Set up an instance of `Button` for each button:
```python
button_a = Button(PIN_BUTTON_A)
button_b = Button(PIN_BUTTON_B)
```
To get the button state, call `.read()`. If the button is held down, then this will return `True` at the interval specified by `repeat_time` until `hold_time` is reached, at which point it will return `True` every `hold_time / 3` milliseconds. This is useful for rapidly increasing/decreasing values such as hue:
```python
state = button_a.read()
```
### RGBLED
Import the `RGBLED` class from `pimoroni` and the pin constants for the buttons:
```python
from pimoroni import RGBLED
from plasma import PIN_LED_R, PIN_LED_G, PIN_LED_B
```
And set up an instance of `RGBLED` for the LED:
```python
led = RGBLED(PIN_LED_R, PIN_LED_G, PIN_LED_B)
```
To set the LED colour, call `.set_rgb(r, g, b)`. Each value should be between 0 and 255:
