Added C-implementation for NeoPixel.

Changed a few colors/animation settings for demo purposes.

Signed-off-by: Dirk Jahnke <dirk@familie-jahnke.de>

src/NeoPixel.c

@@ -0,0 +1,81 @@
+#include "mgos_bitbang.h"
+#include "mgos_gpio.h"
+#include "mgos_system.h"
+
+enum NeoPixel_ColorOrder {
+  RGB = 0,
+  GRB = 1,
+  BGR = 2,
+};
+
+#define MAX_LEDS 100
+static uint8_t NeoPixel_pin = 0;
+static uint8_t NeoPixel_numPixels = 0;
+static uint8_t NeoPixel_leds[3 * MAX_LEDS];
+static NeoPixel_ColorOrder NeoPixel_colorOrder = RGB;
+
+// ## **`NeoPixel_create(pin, numPixels, order)`**
+// Create and return a NeoPixel strip object. Example:
+// ```javascript
+// let pin = 5, numPixels = 16, colorOrder = NeoPixel.GRB;
+// let strip = NeoPixel.create(pin, numPixels, colorOrder);
+// strip.setPixel(0 /* pixel */, 12, 34, 56);
+// strip.show();
+//
+// strip.clear();
+// strip.setPixel(1 /* pixel */, 12, 34, 56);
+// strip.show();
+// ```
+void NeoPixel_create(uint8_t, pin, uint8_t numPixels, enum NeoPixel_ColorOrder order) {
+  mgos_gpio_init();
+  NeoPixel_pin = pin;
+  NeoPixel_numPixels = numPixels;
+  NeoPixel_colorOrder = order;
+  // GPIO.set_mode(pin, GPIO.MODE_OUTPUT);
+  mgos_gpio_set_mode(pin, MGOS_GPIO_MODE_OUTPUT);
+  // GPIO.write(pin, 0);  // Keep in reset.
+  mgos_gpio_write(pin, false);
+  NeoPixel_clear();
+}
+
+// ## **`NeoPixel_clear()`**
+// Clear in-memory values of the pixels.
+void NeoPixel_clear() {
+  for (int i=0; i<NeoPixel_numPixels * 3; ++i) {
+    NeoPixel_leds[i] = 0;
+  }
+}
+
+// ## **`NeoPixel_set(i, r, g, b)`**
+// Set i-th's pixel's RGB value.
+// Note that this only affects in-memory value of the pixel.
+void NeoPixel_set(uint8_t pixel, uint8_t red, uint8_t green, uint8_t blue) {
+  uint8_t v0, v1, v2;
+  if (NeoPixel_colorOrder == RGB) {
+    v0 = red; v1 = green; v2 = blue;
+  } else if (NeoPixel_colorOrder == GRB) {
+    v0 = green; v1 = red; v2 = blue;
+  } else if (NeoPixel_colorOrder == BGR) {
+    v0 = blue; v1 = green; v2 = red;
+  } else return;
+  NeoPixel_leds[pixel] = v0;
+  NeoPixel_leds[pixel+1] = v1;
+  NeoPixel_leds[pixel+2] = v2;
+}
+
+// ## **`NeoPixel_show()`**
+// Output values of the pixels.
+void NeoPixel_show() {
+  // GPIO.write(this.pin, 0);
+  mgos_gpio_write(pin, false);
+  // Sys.usleep(60);
+  mgos_usleep(60);
+  // BitBang.write(this.pin, BitBang.DELAY_100NSEC, 3, 8, 8, 6, this.data, this.len);
+  mgos_bitbang_write_bits(NeoPixel_pin, DELAY_100NSEC, 3, 8, 8, 6, NeoPixel_leds, NeoPixel_numPixels);
+  // GPIO.write(this.pin, 0);
+  mgos_gpio_write(pin, false);
+  // Sys.usleep(60);
+  mgos_usleep(60);
+  // GPIO.write(this.pin, 1);
+  mgos_gpio_write(pin, true);
+}