/*
  This routine writes an array of bytes with RGB values to the Dataout port
  using the fast 800kHz clockless WS2811/2812 protocol.
*/
#include "WS2812.h"

// Timing in ns
#define w_zeropulse   350
#define w_onepulse    900
#define w_totalperiod 1250


void ws2812_init()
{
  ws2812_DDREG |= mask; // Enable DDR
}

#define w_nop1  "nop      \n\t"
#define w_nop2  "rjmp .+0 \n\t"

void ws2812_sendarray(uint8_t *data, uint16_t datlen)
{
  uint8_t curbyte,ctr;
  uint8_t sreg_prev;
  
  sreg_prev=SREG;
  cli();  

  while (datlen--) 
  {
    curbyte=*data++;
    
    asm volatile(
    "       ldi   %0,8  \n\t"
    "loop%=:            \n\t"
    "       st    X,%3 \n\t"    //  '1' [02] '0' [02] - re
    w_nop1
    w_nop2
    "       sbrs  %1,7  \n\t"    //  '1' [04] '0' [03]
    "       st    X,%4 \n\t"     //  '1' [--] '0' [05] - fe-low
    "       lsl   %1    \n\t"    //  '1' [05] '0' [06]
    w_nop1
    w_nop1
    w_nop2
    w_nop2
    "       brcc skipone%= \n\t"    //  '1' [+1] '0' [+2] - 
    "       st   X,%4      \n\t"    //  '1' [+3] '0' [--] - fe-high
    "skipone%=:               "     //  '1' [+3] '0' [+2] - 
    w_nop1
    w_nop2
    "       dec   %0    \n\t"    //  '1' [+4] '0' [+3]
    "       brne  loop%=\n\t"    //  '1' [+5] '0' [+4]
    :  "=&d" (ctr)
    : "r" (curbyte), "x" (&ws2812_PORTREG), "r" (mask), "r" (~mask)
    );
  }
  
  SREG=sreg_prev;  
}