add APA102 lights.

msg/CMakeLists.txt

@@ -50,6 +50,7 @@ set(msg_files
 	airspeed.msg
 	airspeed_validated.msg
 	airspeed_wind.msg
+	apa102_control.msg
 	autotune_attitude_control_status.msg
 	battery_status.msg
 	button_event.msg

msg/apa102_control.msg

@@ -0,0 +1,10 @@
+# Control up to 1001 LEDs on APA102
+
+uint64 timestamp                # time since system start (microseconds)
+
+uint16 number_leds              #total number of leds [0,1001]
+uint8 offset_group              #offset group (multiple of 13) of leds to control [0,77]
+uint32[13] led_values           #follows spi 32 bit LED schema for apa102
+
+# [  PAD 1's  ][ BRIGHT 0:31 ][ BLU 0:255 ][ GRN 0:255 ][ RED 0:255 ]
+# [ 31 ... 29 ][ 28  ...  24 ][ 23 ... 16 ][ 15 ...  8 ][ 7  ...  0 ]