Merge pull request #192 from dereulenspiegel/ws2812

Add support for WS2812 based LED strips

README.md

@@ -125,6 +125,7 @@ pre_build/latest/nodemcu_512k_latest.bin is removed. use pre_build/latest/nodemc
 #define LUA_USE_MODULES_UART
 #define LUA_USE_MODULES_OW
 #define LUA_USE_MODULES_BIT
+#define LUA_USE_MODULES_WS2812
 #endif /* LUA_USE_MODULES */
 ...
 // LUA_NUMBER_INTEGRAL
@@ -330,3 +331,13 @@ cu:send("hello")
 	ds18b20 = nil
     package.loaded["ds18b20"]=nil   
 ```
+
+####Control a WS2812 based light strip
+```lua
+	-- set the color of one LED on GPIO 2 to red
+	ws2812.write(4, string.char(0, 255, 0)) 
+	-- set the color of 10 LEDs on GPIO 0 to blue
+	ws2812.write(3, string.char(0, 0, 255):rep(10))
+	-- first LED green, second LED white
+	ws2812.write(4, string.char(255, 0, 0, 255, 255, 255))
+```

app/include/user_config.h

@@ -64,6 +64,7 @@
 #define LUA_USE_MODULES_OW
 #define LUA_USE_MODULES_BIT
 #define LUA_USE_MODULES_MQTT
+#define LUA_USE_MODULES_WS2812
 #endif /* LUA_USE_MODULES */
 
 // #define LUA_NUMBER_INTEGRAL

app/modules/modules.h

@@ -117,6 +117,15 @@
 #define ROM_MODULES_BIT
 #endif
 
+#if defined(LUA_USE_MODULES_WS2812)
+#define MODULES_WS2812 "ws2812"
+#define ROM_MODULES_WS2812 \
+		_ROM(MODULES_WS2812, luaopen_ws2812, ws2812_map)
+#else
+#define ROM_MODULES_WS2812
+#endif
+
+
 #define LUA_MODULES_ROM      \
         ROM_MODULES_GPIO    \
         ROM_MODULES_PWM		\
@@ -131,7 +140,8 @@
         ROM_MODULES_ADC     \
         ROM_MODULES_UART    \
         ROM_MODULES_OW      \
-        ROM_MODULES_BIT
+        ROM_MODULES_BIT		\
+		ROM_MODULES_WS2812
 
 #endif
 

app/modules/ws2812.c

@@ -0,0 +1,82 @@
+#include "lualib.h"
+#include "lauxlib.h"
+#include "platform.h"
+#include "auxmods.h"
+#include "lrotable.h"
+/**
+ * All this code is mostly from http://www.esp8266.com/viewtopic.php?f=21&t=1143&sid=a620a377672cfe9f666d672398415fcb
+ * from user Markus Gritsch.
+ * I just put this code into its own module and pushed into a forked repo,
+ * to easily create a pull request. Thanks to Markus Gritsch for the code.
+ *
+ */
+
+// ----------------------------------------------------------------------------
+// -- This WS2812 code must be compiled with -O2 to get the timing right.
+// -- http://wp.josh.com/2014/05/13/ws2812-neopixels-are-not-so-finicky-once-you-get-to-know-them/
+// The ICACHE_FLASH_ATTR is there to trick the compiler and get the very first pulse width correct.
+static void ICACHE_FLASH_ATTR send_ws_0(uint8_t gpio) {
+  uint8_t i;
+  i = 4;
+  while (i--)
+    GPIO_REG_WRITE(GPIO_OUT_W1TS_ADDRESS, 1 << gpio);
+  i = 9;
+  while (i--)
+    GPIO_REG_WRITE(GPIO_OUT_W1TC_ADDRESS, 1 << gpio);
+}
+
+static void ICACHE_FLASH_ATTR send_ws_1(uint8_t gpio) {
+  uint8_t i;
+  i = 8;
+  while (i--)
+    GPIO_REG_WRITE(GPIO_OUT_W1TS_ADDRESS, 1 << gpio);
+  i = 6;
+  while (i--)
+    GPIO_REG_WRITE(GPIO_OUT_W1TC_ADDRESS, 1 << gpio);
+}
+
+// Lua: ws2812.write(pin, "string")
+// Byte triples in the string are interpreted as G R B values.
+// ws2812.write(4, string.char(0, 255, 0)) uses GPIO2 and sets the first LED red.
+// ws2812.write(3, string.char(0, 0, 255):rep(10)) uses GPIO0 and sets ten LEDs blue.
+// ws2812.write(4, string.char(255, 0, 0, 255, 255, 255)) first LED green, second LED white.
+static int ICACHE_FLASH_ATTR ws2812_write(lua_State* L) {
+  const uint8_t pin = luaL_checkinteger(L, 1);
+  size_t length;
+  const char *buffer = luaL_checklstring(L, 2, &length);
+
+  platform_gpio_mode(pin, PLATFORM_GPIO_OUTPUT, PLATFORM_GPIO_FLOAT);
+  platform_gpio_write(pin, 0);
+  os_delay_us(10);
+
+  os_intr_lock();
+  const char * const end = buffer + length;
+  while (buffer != end) {
+    uint8_t mask = 0x80;
+    while (mask) {
+      (*buffer & mask) ? send_ws_1(pin_num[pin]) : send_ws_0(pin_num[pin]);
+      mask >>= 1;
+    }
+    ++buffer;
+  }
+  os_intr_unlock();
+
+  return 0;
+}
+
+#define MIN_OPT_LEVEL 2
+#include "lrodefs.h"
+const LUA_REG_TYPE ws2812_map[] =
+{
+  { LSTRKEY( "write" ), LFUNCVAL( ws2812_write )},
+  { LNILKEY, LNILVAL}
+};
+
+LUALIB_API int luaopen_ws2812(lua_State *L) {
+  // TODO: Make sure that the GPIO system is initialized
+  LREGISTER(L, "ws2812", ws2812_map);
+  return 1;
+}
+
+// ----------------------------------------------------------------------------
+