# LED

    identifier: 0x1609d4f0
    camel: led
    group: light
    status: stable

A controller for displays of individually controlled RGB LEDs.

For 64 or less LEDs, the service should support the pack the pixels in the pixels register.
Beyond this size, the register should return an empty payload as the amount of data exceeds
the size of a packet. Typically services that use more than 64 LEDs
will run on the same MCU and will maintain the pixels buffer internally.

## Registers

    define max_pixels_length 64
    rw pixels: bytes @ value

A buffer of 24bit RGB color entries for each LED, in R, G, B order.
When writing, if the buffer is too short, the remaining pixels are set to `#000000`;
If the buffer is too long, the write may be ignored, or the additional pixels may be ignored.
If the number of pixels is greater than `max_pixels_length`, the read should return an empty payload.

    rw brightness = 0.05: u0.8 / @ intensity

Set the luminosity of the strip.
At `0` the power to the strip is completely shut down.

    ro actual_brightness: u0.8 / @ 0x180

This is the luminosity actually applied to the strip.
May be lower than `brightness` if power-limited by the `max_power` register.
It will rise slowly (few seconds) back to `brightness` is limits are no longer required.

    const num_pixels: u16 # @ 0x182

Specifies the number of pixels in the strip.

    const num_columns?: u16 # @ 0x183

If the LED pixel strip is a matrix, specifies the number of columns.

    rw max_power? = 200: u16 mA @ max_power

Limit the power drawn by the light-strip (and controller).

    const leds_per_pixel?: u16 # @ 0x184

If known, specifies the number of LEDs in parallel on this device.
The actual number of LEDs is `num_pixels * leds_per_pixel`.

    const wave_length?: u16 nm { typical_min=365, typical_max=885 } @ 0x185

If monochrome LED, specifies the wave length of the LED.
Register is missing for RGB LEDs.

    const luminous_intensity?: u16 mcd { typical_min=10, typical_max=5000 } @ 0x186

The luminous intensity of all the LEDs, at full brightness, in micro candella.

    enum Variant: u8 {
        Strip = 1,
        Ring = 2,
        Stick = 3,
        Jewel = 4,
        Matrix = 5
    }
    const variant?: Variant @ variant

Specifies the shape of the light strip.