Support for NeoPixel LEDs. More...

Data Structures
struct	neopixel_data_t
	Individual data block for a NeoPixel: 24-bit color green-red-blue sent MSb first. More...

Macros
#define	NEOPIXEL_CHANNEL_COUNT (3U)
	Number of color channels per neopixel.

#define	NEOPIXEL_COLOR_BITS (NEOPIXEL_CHANNEL_COUNT * 8U)
	Total number of bits for a single NeoPixel.

#define	NEOPIXEL_CODE_T0H_NS (300U)
	Period of the 0-NRZ-code high assertion time, in nanoseconds.

#define	NEOPIXEL_CODE_T0L_NS (900U)
	Period of the 0-NRZ-code low assertion time, in nanoseconds.

#define	NEOPIXEL_CODE_T1H_NS (600U)
	Period of the 1-NRZ-code high assertion time, in nanoseconds.

#define	NEOPIXEL_CODE_T1L_NS (600U)
	Period of the 1-NRZ-code low assertion time, in nanoseconds.

#define	NEOPIXEL_CODE_TBIT_NS (1200U)
	Total period, in nanoseconds, for the high and low portions of the NRZ bit codes.

#define	NEOPIXEL_CODE_TRST_NS (80000U)
	Minumum period, in nanoseconds, of the reset code.

#define	NEOPIXEL_GAMMA_CORRECTION_DEFAULT (2.8f)
	Default gamma correction factor for NeoPixels. More...

Detailed Description

Support for NeoPixel LEDs.

NeoPixel Timing Requirements

Data codes

NeoPixels use a NRZ (non-return-to-zero) code with a fixed timing width to transmit color data.

 Code  | Timing waveform
------ | ----------------------------------------------------------------------
       |      |<------- 1.20 us ----->|        (Nominal 1.25±0.6 us ≈ 800 kHz)
       |       _______
   0   |   XXX|       |________________XXX
       |      |<-T0H->|<-     TOL   ->|
       |        (0.3)        (0.9)                         us (25% duty-cycle)
       |
       |       ___________
   1   |   XXX|           |____________XXX
       |      |<-  T1H  ->|<-  T1L  ->|
       |          (0.6)      (0.6)                         us (50% duty-cycle)
       |
  RST  |   XXX_____________________________________XXX
       |      |<-              TRST             ->|
       |                       (80)                        us

Data transmission

Data is transmitted during each refresh cycle. All NeoPixels color codes are transmitted in sequence followed by a reset code. Each subsequent NeoPixel re-transmits any bit codes that follow after reception of its data.

NeoPixel  | Data                                | Reset   | Data                               | Reset    
--------- | ----------------------------------- | ------- | ---------------------------------- | --------
          |                                     |         |                                    |
          | <--------------- Data frame 1 --------------->|<--------------- Data frame 2 --------------->
          |     Data1       Data2       Data3   |         |   Data1        Data2       Data3   |
    D1    |_<̅_̅_̅_̅_̅_̅_̅_̅_̅_̅_̅_><̅_̅_̅_̅_̅_̅_̅_̅_̅_̅_̅_><̅_̅_̅_̅_̅_̅_̅_̅_̅_̅_̅_>____//____<̅_̅_̅_̅_̅_̅_̅_̅_̅_̅_̅_̅_><̅_̅_̅_̅_̅_̅_̅_̅_̅_̅_̅_><̅_̅_̅_̅_̅_̅_̅_̅_̅_̅_̅_>____//____
          | <G1><R1><B1><G2><R2><B2><G3><R3><B3>|         |<G1><R1><B1><G2><R2><B2><G3><R3><B3>|
    D2    |_____________<̅_̅_̅_̅_̅_̅_̅_̅_̅_̅_̅_><̅_̅_̅_̅_̅_̅_̅_̅_̅_̅_̅_>____//_________________<̅_̅_̅_̅_̅_̅_̅_̅_̅_̅_̅_><̅_̅_̅_̅_̅_̅_̅_̅_̅_̅_̅_>____//____
          |             <G2><R2><B2><G3><R3><B3>|         |            <G2><R2><B2><G3><R3><B3>|
    D3    |_________________________<̅_̅_̅_̅_̅_̅_̅_̅_̅_̅_̅_>____//_____________________________<̅_̅_̅_̅_̅_̅_̅_̅_̅_̅_̅_>____//____
          |                         <G3><R3><B3>|         |                        <G3><R3><B3>|
    D4    |_________________________________________//_____________________________________________//____
          |                                     |         |                                    |

Macro Definition Documentation

◆ NEOPIXEL_GAMMA_CORRECTION_DEFAULT

#define NEOPIXEL_GAMMA_CORRECTION_DEFAULT (2.8f)

Default gamma correction factor for NeoPixels.

From: https://learn.adafruit.com/led-tricks-gamma-correction/the-longer-fix.