Controls a NeoPixel using an RFDuino board with functions that resemble the NeoPixel API

raw_neopixel_rfduino.ino

// WS2812_RFduino_Test
// By Thomas Olson
// teo20140220.01
// teo20140719.01 Modified for Arduino 1.5.7
// 20141022.. verified works with Arduino 1.5.8
// No complicated Pixel Library needed.
// Tested with WS2812B 4 pin versions.
// Modified by Sam Decrock to resemble NeoPixel API

const int ws2812pin = 6;
const int nPIXELS = 60;

const int nLEDs = nPIXELS * 3;
uint8_t ledBar[nLEDs];
uint8_t brightness = 255;

void setup() {
  pinMode(ws2812pin, OUTPUT);
  digitalWrite(ws2812pin, LOW);
  clearStrip();
  delay(1);
}


// Taken from neopixel strandtest:
void loop() {
  colorWipe(Color(255, 0, 0), 50); // Red
  colorWipe(Color(0, 255, 0), 50); // Green
  colorWipe(Color(0, 0, 255), 50); // Blue
}

// Fill the dots one after the other with a color
void colorWipe(uint32_t color, uint8_t wait) {
  for(uint16_t i=0; i<nPIXELS; i++) {
      setPixelColor(i, color);
      showStrip();
      delay(wait);
  }
}

// ============================
// NeoPixel API like functions:
// ============================

uint32_t Color(uint8_t r, uint8_t g, uint8_t b) {
  return ((uint32_t)r << 16) | ((uint32_t)g <<  8) | b;
}

void setPixelColor(int pixel, uint32_t color) {
  uint8_t red = (uint8_t)(color >> 16);
  uint8_t green = (uint8_t)(color >>  8);
  uint8_t blue = (uint8_t)color;
  
  red = (red * brightness) >> 8;
  green = (green * brightness) >> 8;
  blue = (blue * brightness) >> 8;
  
  setPixelColor(pixel, red, green, blue);
}

void setPixelColor(int pixel, byte red, byte green, byte blue) {
  ledBar[3*pixel] = green;
  ledBar[3*pixel+1] = red;
  ledBar[3*pixel+2] = blue;
}


void clearStrip() {
  for(uint32_t i; i<64; i++) {
    setPixelColor(i, 0);
  }
  showStrip();
}

void showStrip(){
  noInterrupts();
  for(int wsOut = 0; wsOut < nLEDs; wsOut++){
    for(int x=7; x>=0; x--){
      NRF_GPIO->OUTSET = (1UL << ws2812pin);
      if(ledBar[wsOut] & (0x01 << x)) {
        __ASM ( \
              " NOP\n\t" \
              " NOP\n\t" \
              " NOP\n\t" \
              " NOP\n\t" \
              " NOP\n\t" \
              );
        NRF_GPIO->OUTCLR = (1UL << ws2812pin);
      
      }else{
        NRF_GPIO->OUTCLR = (1UL << ws2812pin);
        __ASM ( \
              " NOP\n\t" \
              " NOP\n\t" \
              " NOP\n\t" \
              );      
      }
    }
  }
  delayMicroseconds(50); // latch and reset WS2812.
  interrupts();  
}

Update - took the delayMicroseconds all the way down to (1) and seems to have solved the problem. LED's still work, and Simblee hasn't lost the connection to my phone in almost an hour. Hope this might be helpful for others.