Arduino WS2812 control

Projects Programming
10

first of all you will have to set the pinmode in begin()

void Adafruit_NeoPixel::begin(void) {
  if(pin >= 0) {
    pinMode(pin, OUTPUT);
    digitalWrite(pin, LOW);
  }
  begun = true;
}

Hence my question.
Then in show() if it is a 16MHz AVR, it should not be such a big deal

// 16 MHz(ish) AVR --------------------------------------------------------
#elif (F_CPU >= 15400000UL) && (F_CPU <= 19000000L)

#ifdef NEO_KHZ400 // 800 KHz check needed only if 400 KHz support enabled
  if(is800KHz) {
#endif

    // WS2811 and WS2812 have different hi/lo duty cycles; this is
    // similar but NOT an exact copy of the prior 400-on-8 code.

    // 20 inst. clocks per bit: HHHHHxxxxxxxxLLLLLLL
    // ST instructions:         ^   ^        ^       (T=0,5,13)

    volatile uint8_t next, bit;

    hi   = *port |  pinMask;
    lo   = *port & ~pinMask;
    next = lo;
    bit  = 8;

because this is how it is defined. A lot less complex than writing a port specific ASM as for slower clock rates.