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.
## APA102
### Getting Started
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.
```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`:
```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.
## WS2812
### Getting Started
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:
