ESP8266 support (based on Makuna's NeoPixelBus lib)

Adafruit_NeoPixel.cpp

@@ -7,7 +7,8 @@
   (possible exception with upper PORT registers on the Arduino Mega).
 
   Written by Phil Burgess / Paint Your Dragon for Adafruit Industries,
-  contributions by PJRC and other members of the open source community.
+  contributions by PJRC, Michael Miller and other members of the open
+  source community.
 
   Adafruit invests time and resources providing this open source code,
   please support Adafruit and open-source hardware by purchasing products
@@ -70,6 +71,13 @@ void Adafruit_NeoPixel::begin(void) {
   digitalWrite(pin, LOW);
 }
 
+
+#ifdef 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);
+#endif // ESP8266
+
 void Adafruit_NeoPixel::show(void) {
 
   if(!pixels) return;
@@ -97,7 +105,9 @@ void Adafruit_NeoPixel::show(void) {
 
   noInterrupts(); // Need 100% focus on instruction timing
 
+
 #ifdef __AVR__
+// AVR MCUs -- ATmega & ATtiny (no XMEGA) ---------------------------------
 
   volatile uint16_t
     i   = numBytes; // Loop counter
@@ -377,7 +387,7 @@ void Adafruit_NeoPixel::show(void) {
         [lo]    "r" (lo),
         [ptr]   "e" (ptr));
   }
-#endif
+#endif // NEO_KHZ400
 
 // 12 MHz(ish) AVR --------------------------------------------------------
 #elif (F_CPU >= 11100000UL) && (F_CPU <= 14300000UL)
@@ -557,7 +567,7 @@ void Adafruit_NeoPixel::show(void) {
         [lo]     "r" (lo),
         [ptr]    "e" (ptr));
   }
-#endif
+#endif // NEO_KHZ400
 
 // 16 MHz(ish) AVR --------------------------------------------------------
 #elif (F_CPU >= 15400000UL) && (F_CPU <= 19000000L)
@@ -669,14 +679,19 @@ void Adafruit_NeoPixel::show(void) {
         [hi]     "r" (hi),
         [lo]     "r" (lo));
   }
-#endif
+#endif // NEO_KHZ400
 
 #else
  #error "CPU SPEED NOT SUPPORTED"
-#endif
+#endif // end F_CPU ifdefs on __AVR__
+
+// END AVR ----------------------------------------------------------------
+
 
 #elif defined(__arm__)
 
+// ARM MCUs -- Teensy 3.0, 3.1, LC, Arduino Due ---------------------------
+
 #if defined(__MK20DX128__) || defined(__MK20DX256__) // Teensy 3.0 & 3.1
 #define CYCLES_800_T0H  (F_CPU / 4000000)
 #define CYCLES_800_T1H  (F_CPU / 1250000)
@@ -732,11 +747,7 @@ void Adafruit_NeoPixel::show(void) {
     }
     while(ARM_DWT_CYCCNT - cyc < CYCLES_400);
   }
-#endif
-
-
-
-
+#endif // NEO_KHZ400
 
 #elif defined(__MKL26Z64__) // Teensy-LC
 
@@ -822,10 +833,9 @@ void Adafruit_NeoPixel::show(void) {
   );
 #else
 #error "Sorry, only 48 MHz is supported, please set Tools > CPU Speed to 48 MHz"
-#endif
+#endif // F_CPU == 48000000
 
-
-#else // Arduino Due
+#else // Other ARM architecture -- Presumed Arduino Due
 
   #define SCALE      VARIANT_MCK / 2UL / 1000000UL
   #define INST       (2UL * F_CPU / VARIANT_MCK)
@@ -888,9 +898,23 @@ void Adafruit_NeoPixel::show(void) {
   while(*timeValue < period); // Wait for last bit
   TC_Stop(TC1, 0);
 
-#endif // end Arduino Due
+#endif // end Due
+
+// END ARM ----------------------------------------------------------------
+
+
+#elif defined(ESP8266)
+
+// ESP8266 ----------------------------------------------------------------
+
+  // ESP8266 show() is external to enforce ICACHE_RAM_ATTR execution
+  espShow(pin, pixels, numBytes, type);
+
+#endif // ESP8266
+
+
+// END ARCHITECTURE SELECT ------------------------------------------------
 
-#endif // end Architecture select
 
   interrupts();
   endTime = micros(); // Save EOD time for latch on next call

esp8266.c

@@ -0,0 +1,67 @@
+// This is a mash-up of the Due show() code + insights from Michael Miller's
+// 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
+
+#include <Arduino.h>
+#include <eagle_soc.h>
+
+static uint32_t _getCycleCount(void) __attribute__((always_inline));
+static inline uint32_t _getCycleCount(void) {
+  uint32_t ccount;
+  __asm__ __volatile__("rsr %0,ccount":"=a" (ccount));
+  return ccount;
+}
+
+void ICACHE_RAM_ATTR espShow(
+ uint8_t pin, uint8_t *pixels, uint32_t numBytes, uint8_t type) {
+
+#define CYCLES_800_T0H  (F_CPU / 2500000) // 0.4us
+#define CYCLES_800_T1H  (F_CPU / 1250000) // 0.8us
+#define CYCLES_800      (F_CPU /  800000) // 1.25us per bit
+#define CYCLES_400_T0H  (F_CPU / 2000000) // 0.5uS
+#define CYCLES_400_T1H  (F_CPU /  833333) // 1.2us
+#define CYCLES_400      (F_CPU /  400000) // 2.5us per bit
+
+  uint8_t *p, *end, pix, mask;
+  uint32_t t, time0, time1, period, c, startTime, pinMask;
+
+  pinMask   = _BV(pin);
+  p         =  pixels;
+  end       =  p + numBytes;
+  pix       = *p++;
+  mask      = 0x80;
+  startTime = 0;
+
+#ifdef NEO_KHZ400
+  if((type & NEO_SPDMASK) == NEO_KHZ800) { // 800 KHz bitstream
+#endif
+    time0  = CYCLES_800_T0H;
+    time1  = CYCLES_800_T1H;
+    period = CYCLES_800;
+#ifdef NEO_KHZ400
+  } else { // 400 KHz bitstream
+    time0  = CYCLES_400_T0H;
+    time1  = CYCLES_400_T1H;
+    period = CYCLES_800;
+  }
+#endif
+
+  for(t = time0;; t = time0) {
+    if(pix & mask) t = time1;                             // Bit high duration
+    while(((c = _getCycleCount()) - startTime) < period); // Wait for bit start
+    GPIO_REG_WRITE(GPIO_OUT_W1TS_ADDRESS, pinMask);       // Set high
+    startTime = c;                                        // Save start time
+    while(((c = _getCycleCount()) - startTime) < t);      // Wait high duration
+    GPIO_REG_WRITE(GPIO_OUT_W1TC_ADDRESS, pinMask);       // Set low
+    if(!(mask >>= 1)) {                                   // Next bit/byte
+      if(p >= end) break;
+      pix  = *p++;
+      mask = 0x80;
+    }
+  }
+  while((_getCycleCount() - startTime) < period); // Wait for last bit
+}
+
+#endif // ESP8266

examples/strandtest/strandtest.ino

@@ -1,5 +1,5 @@
 #include <Adafruit_NeoPixel.h>
-#include <avr/power.h>
+#include <avr/power.h> // Comment out this line for non-AVR boards (Arduino Due, etc.)
 
 #define PIN 6
 

library.properties

@@ -1,5 +1,5 @@
 name=Adafruit NeoPixel
-version=1.0
+version=1.0.1
 author=Adafruit
 maintainer=Adafruit <[email protected]>
 sentence=Arduino library for controlling single-wire-based LED pixels and strip.