UART driven neopixels using Serial1

NeoPixelBus.cpp

@@ -32,12 +32,28 @@ License along with NeoPixel.  If not, see
 #include "NeoPixelBus.h"
 
 #if defined(ESP8266)
-// due to linker overriding the ICACHE_RAM_ATTR for cpp files, these methods are
+
-// moved into a C file so the attribute will be applied correctly
+    #ifdef ESPUARTWS2812
-extern "C" void ICACHE_RAM_ATTR send_pixels_800(uint8_t* pixels, uint8_t* end, uint8_t pin);
+        extern "C" {
-extern "C" void ICACHE_RAM_ATTR send_pixels_400(uint8_t* pixels, uint8_t* end, uint8_t pin);
+        #include "eagle_soc.h"
+        #include "uart_register.h"
+        #include <Arduino.h>
+        }
+        #define UART_INV_MASK  (0x3f<<19)
+        #define UART 1
+
+    #else
+        // due to linker overriding the ICACHE_RAM_ATTR for cpp files, these methods are
+        // moved into a C file so the attribute will be applied correctly
+        extern "C" void ICACHE_RAM_ATTR send_pixels_800(uint8_t* pixels, uint8_t* end, uint8_t pin);
+        extern "C" void ICACHE_RAM_ATTR send_pixels_400(uint8_t* pixels, uint8_t* end, uint8_t pin);
+    #endif
+
 #endif
 
+
+
+
 NeoPixelBus::NeoPixelBus(uint16_t n, uint8_t p, uint8_t t) : 
     _countPixels(n), 
     _sizePixels(n * 3), 
@@ -46,7 +62,11 @@ NeoPixelBus::NeoPixelBus(uint16_t n, uint8_t p, uint8_t t) :
     _activeAnimations(0),
     _flagsPixels(t)
 {
+
+#ifndef ESPUARTWS2812
     setPin(p);
+#endif
+
 
     _pixels = (uint8_t *)malloc(_sizePixels);
     if (_pixels) 
@@ -69,16 +89,28 @@ NeoPixelBus::~NeoPixelBus()
     if (_animations) 
         free(_animations);
 
+#ifndef ESPUARTWS2812
     pinMode(_pin, INPUT);
+#endif
+
 }
 
-void NeoPixelBus::Begin(void) 
+ void NeoPixelBus::Begin(void) 
-{
+ {
-    pinMode(_pin, OUTPUT);
+
-    digitalWrite(_pin, LOW);
+#ifdef ESPUARTWS2812 
+    /* Serial rate is 4x 800KHz for WS2811 */
+    Serial1.begin(3200000, SERIAL_6N1, SERIAL_TX_ONLY);
+    CLEAR_PERI_REG_MASK(UART_CONF0(UART), UART_INV_MASK);
+    //SET_PERI_REG_MASK(UART_CONF0(UART), UART_TXD_INV);
+    SET_PERI_REG_MASK(UART_CONF0(UART), (BIT(22)));
+#else  
+     pinMode(_pin, OUTPUT);
+     digitalWrite(_pin, LOW);
+#endif
+     Dirty();
+ }
 
-    Dirty();
-}
 
 void NeoPixelBus::Show(void) 
 {
@@ -111,7 +143,9 @@ void NeoPixelBus::Show(void)
     // state, computes 'pin high' and 'pin low' values, and writes these back
     // to the PORT register as needed.
 
+#ifndef ESPUARTWS2812
     noInterrupts(); // Need 100% focus on instruction timing
+#endif 
 
 #ifdef __AVR__
 
@@ -724,8 +758,28 @@ void NeoPixelBus::Show(void)
     if ((_flagsPixels & NEO_SPDMASK) == NEO_KHZ800)
     {
 #endif
+#ifndef ESPUARTWS2812        
         // 800 KHz bitstream
         send_pixels_800(p, end, _pin);
+#else 
+
+    char buff[4];
+
+    do
+    {
+        uint8_t subpix = *p++;
+
+        buff[0] = data[(subpix >> 6) & 3];
+        buff[1] = data[(subpix >> 4) & 3];
+        buff[2] = data[(subpix >> 2) & 3];
+        buff[3] = data[subpix & 3];
+        Serial1.write(buff, sizeof(buff));    
+
+    } while (p < end);
+
+
+
+#endif 
 
 #ifdef INCLUDE_NEO_KHZ400_SUPPORT
     }
@@ -973,7 +1027,10 @@ void NeoPixelBus::Show(void)
 
 #endif // end Architecture select
 
+#ifndef ESPUARTWS2812
     interrupts();
+#endif
+
     ResetDirty();
     _endTime = micros(); // Save EOD time for latch on next call
 }

NeoPixelBus.h

@@ -20,6 +20,8 @@ License along with NeoPixel.  If not, see
 #include <Arduino.h>
 #include "RgbColor.h"
 
+#define ESPUARTWS2812 // drive neopixels by UART on GPIO2 on ESP8266 thanks to Forkineye. https://github.com/forkineye/ESPixelStick
+
 // '_flagsPixels' flags for LED _pixels (third parameter to constructor):
 #define NEO_RGB     0x00 // Wired for RGB data order
 #define NEO_GRB     0x01 // Wired for GRB data order
@@ -120,6 +122,12 @@ private:
     uint8_t _pinMask;       // Output PORT bitmask
 #endif
 
+#ifdef ESPUARTWS2812
+    /* 6 bit UART lookup table, first 2 bits ignored. Start and stop bits are part of the pixel stream. */
+const char data[4] = { 0b00110111, 0b00000111, 0b00110100, 0b00000100 };
+#endif
+
+
     struct FadeAnimation
     {
         uint16_t time;