WS2812 example: Improve supported bandwidths (#486)

Adjusts constants to 3,3,4 to support higher bandwidths on any of WS2812, WS2812B, and SK6812 LEDs.

pio/ws2812/ws2812.pio

@@ -7,9 +7,13 @@
 .program ws2812
 .side_set 1
 
-.define public T1 2
-.define public T2 5
-.define public T3 3
+; The following constants are selected for broad compatibility with WS2812,
+; WS2812B, and SK6812 LEDs. Other constants may support higher bandwidths for
+; specific LEDs, such as (7,10,8) for WS2812B LEDs.
+
+.define public T1 3
+.define public T2 3
+.define public T3 4
 
 .lang_opt python sideset_init = pico.PIO.OUT_HIGH
 .lang_opt python out_init     = pico.PIO.OUT_HIGH
@@ -49,9 +53,9 @@ static inline void ws2812_program_init(PIO pio, uint sm, uint offset, uint pin,
 
 .program ws2812_parallel
 
-.define public T1 2
-.define public T2 5
-.define public T3 3
+.define public T1 3
+.define public T2 3
+.define public T3 4
 
 .wrap_target
     out x, 32