Additions and improvements to WS2812 chainable leds support

diff --git a/extdrv/ws2812.c b/extdrv/ws2812.c
index c379c16..f6ac983 100644 (file)
--- a/extdrv/ws2812.c
+++ b/extdrv/ws2812.c
@@ -21,7 +21,7 @@
  *************************************************************************** */
 
 /*
- * Support for the WS2812 Chainable RGB Leds
+ * Support for the WS2812 and WS2812B Chainable RGB Leds
  *
  * WS2812 protocol can be found here : https://www.adafruit.com/datasheets/WS2812.pdf
  *
@@ -48,7 +48,7 @@ void ws2812_config(const struct pio* gpio)
 }
 
 static uint8_t led_data[NB_LEDS * 3];
-static uint16_t max_led = 0;
+static int16_t max_led = -1;
 static uint32_t nb_bytes = 0;
 
 
@@ -136,7 +136,12 @@ int ws2812_send_frame(uint16_t nb_leds)
                return -1;
        }
        if (nb_leds == 0) {
+               if (max_led == -1) {
+                       return 0;
+               }
                nb_leds = max_led;
+               /* All leds set previously will be sent, back to no leds set */
+               max_led = -1;
        }
        nb_bytes = (nb_leds + 1) * 3;
        ws2812_bit_sender();
@@ -159,12 +164,23 @@ int ws2812_set_pixel(uint16_t pixel_num, uint8_t red, uint8_t green, uint8_t blu
        }
        return 0;
 }
+/* Get a pixel (led) color from the data buffer */
+int ws2812_get_pixel(uint16_t pixel_num, uint8_t* red, uint8_t* green, uint8_t* blue)
+{
+       if (pixel_num >= NB_LEDS) {
+               return -1;
+       }
+       *green = led_data[ ((pixel_num * 3) + 0) ];
+       *red = led_data[ ((pixel_num * 3) + 1) ];
+       *blue = led_data[ ((pixel_num * 3) + 2) ];
+       return 0;
+}
 
 /* Clear the internal data buffer. */
 void ws2812_clear_buffer(void)
 {
        memset(led_data, 0, (NB_LEDS * 3));
-       max_led = 0;
+       max_led = -1;
 }
 
 /* Clear the internal data buffer and send it to the Leds, turning them all off */
@@ -173,7 +189,7 @@ void ws2812_clear(void)
        /* Start at first led and send all leds off */
        ws2812_clear_buffer();
        ws2812_send_frame(NB_LEDS);
-       max_led = 0;
+       max_led = -1;
 }
 
 void ws2812_stop(void) __attribute__ ((alias ("ws2812_clear")));

diff --git a/include/extdrv/ws2812.h b/include/extdrv/ws2812.h
index 1026e99..486af0c 100644 (file)
--- a/include/extdrv/ws2812.h
+++ b/include/extdrv/ws2812.h
@@ -88,6 +88,15 @@ int ws2812_send_frame(uint16_t nb_leds);
  */
 int ws2812_set_pixel(uint16_t pixel_num, uint8_t red, uint8_t green, uint8_t blue);
 
+/* Read the value of a pixel (led) color from the data buffer (frame)
+ * The returned value is the last value set using ws2812_set_pixel(), but not
+ *   necessarily the actual color of the led if ws2812_send_frame() has not been
+ *   called with a big enough value. It is the value that would be set when using
+ *   ws2812_send_frame() with 0 or with a value equal to or above the pixel number
+ *   in the ws2812_get_pixel() call.
+ */
+int ws2812_get_pixel(uint16_t pixel_num, uint8_t* red, uint8_t* green, uint8_t* blue);
+
 /* Clear the internal data buffer. */
 void ws2812_clear_buffer(void);