Added ESP32 support.

Modified library so that it refuses to build on an unknown architecture
instead of building and then doing nothing.

Added ESP32 support, which might not be optimal, but seems to work for
me.

Adafruit_NeoPixel.cpp

@@ -101,10 +101,13 @@ void Adafruit_NeoPixel::updateType(neoPixelType t) {
   }
 }
 
-#ifdef ESP8266
+#if defined(ESP8266) 
 // ESP8266 show() is external to enforce ICACHE_RAM_ATTR execution
 extern "C" void ICACHE_RAM_ATTR espShow(
   uint8_t pin, uint8_t *pixels, uint32_t numBytes, uint8_t type);
+#elif defined(ESP32)
+extern "C" void espShow(
+  uint8_t pin, uint8_t *pixels, uint32_t numBytes, uint8_t type);
 #endif // ESP8266
 
 void Adafruit_NeoPixel::show(void) {
@@ -1411,7 +1414,7 @@ void Adafruit_NeoPixel::show(void) {
 // END ARM ----------------------------------------------------------------
 
 
-#elif defined(ESP8266)
+#elif defined(ESP8266) || defined(ESP32)
 
 // ESP8266 ----------------------------------------------------------------
 
@@ -1512,6 +1515,8 @@ void Adafruit_NeoPixel::show(void) {
     }
   }
 
+#else 
+#error Architecture not supported
 #endif
 
 

esp8266.c

@@ -2,10 +2,12 @@
 // ESP8266 work for the NeoPixelBus library: github.com/Makuna/NeoPixelBus
 // Needs to be a separate .c file to enforce ICACHE_RAM_ATTR execution.
 
-#ifdef ESP8266
+#if defined(ESP8266) || defined(ESP32)
 
 #include <Arduino.h>
+#ifdef ESP8266
 #include <eagle_soc.h>
+#endif
 
 static uint32_t _getCycleCount(void) __attribute__((always_inline));
 static inline uint32_t _getCycleCount(void) {
@@ -14,8 +16,13 @@ static inline uint32_t _getCycleCount(void) {
   return ccount;
 }
 
+#ifdef ESP8266
 void ICACHE_RAM_ATTR espShow(
  uint8_t pin, uint8_t *pixels, uint32_t numBytes, boolean is800KHz) {
+#else
+void espShow(
+ uint8_t pin, uint8_t *pixels, uint32_t numBytes, boolean is800KHz) {
+#endif
 
 #define CYCLES_800_T0H  (F_CPU / 2500000) // 0.4us
 #define CYCLES_800_T1H  (F_CPU / 1250000) // 0.8us
@@ -51,10 +58,18 @@ void ICACHE_RAM_ATTR espShow(
   for(t = time0;; t = time0) {
     if(pix & mask) t = time1;                             // Bit high duration
     while(((c = _getCycleCount()) - startTime) < period); // Wait for bit start
+#ifdef ESP8266
     GPIO_REG_WRITE(GPIO_OUT_W1TS_ADDRESS, pinMask);       // Set high
+#else
+    gpio_set_level(pin, HIGH);
+#endif
     startTime = c;                                        // Save start time
     while(((c = _getCycleCount()) - startTime) < t);      // Wait high duration
+#ifdef ESP8266
     GPIO_REG_WRITE(GPIO_OUT_W1TC_ADDRESS, pinMask);       // Set low
+#else
+    gpio_set_level(pin, LOW);
+#endif
     if(!(mask >>= 1)) {                                   // Next bit/byte
       if(p >= end) break;
       pix  = *p++;