1 files changed, 59 insertions, 0 deletions
diff --git a/examples/rp2/pio_ws2812.py b/examples/rp2/pio_ws2812.py
new file mode 100644
index 000000000..dd021a9d5
--- /dev/null
+++ b/examples/rp2/pio_ws2812.py
@@ -0,0 +1,59 @@
+# Example using PIO to drive a set of WS2812 LEDs.
+
+import array, time
+from machine import Pin
+import rp2
+
+# Configure the number of WS2812 LEDs.
+NUM_LEDS = 8
+
+
+@rp2.asm_pio(
+    sideset_init=rp2.PIO.OUT_LOW,
+    out_shiftdir=rp2.PIO.SHIFT_LEFT,
+    autopull=True,
+    pull_thresh=24,
+)
+def ws2812():
+    # fmt: off
+    T1 = 2
+    T2 = 5
+    T3 = 3
+    wrap_target()
+    label("bitloop")
+    out(x, 1)               .side(0)    [T3 - 1]
+    jmp(not_x, "do_zero")   .side(1)    [T1 - 1]
+    jmp("bitloop")          .side(1)    [T2 - 1]
+    label("do_zero")
+    nop()                   .side(0)    [T2 - 1]
+    wrap()
+    # fmt: on
+
+
+# Create the StateMachine with the ws2812 program, outputting on Pin(22).
+sm = rp2.StateMachine(0, ws2812, freq=8_000_000, sideset_base=Pin(22))
+
+# Start the StateMachine, it will wait for data on its FIFO.
+sm.active(1)
+
+# Display a pattern on the LEDs via an array of LED RGB values.
+ar = array.array("I", [0 for _ in range(NUM_LEDS)])
+
+# Cycle colours.
+for i in range(4 * NUM_LEDS):
+    for j in range(NUM_LEDS):
+        r = j * 100 // (NUM_LEDS - 1)
+        b = 100 - j * 100 // (NUM_LEDS - 1)
+        if j != i % NUM_LEDS:
+            r >>= 3
+            b >>= 3
+        ar[j] = r << 16 | b
+    sm.put(ar, 8)
+    time.sleep_ms(50)
+
+# Fade out.
+for i in range(24):
+    for j in range(NUM_LEDS):
+        ar[j] = ar[j] >> 1 & 0x7F7F7F
+    sm.put(ar, 8)
+    time.sleep_ms(50)