chore(swan_r5):pwmio test

Author: m-mcgowan

ports/stm/boards/swan_r5/tests/pwnio.py

@@ -0,0 +1,18 @@
+import time
+import pwmio
+
+
+def fade(pin):
+    led = pwmio.PWMOut(pin, frequency=5000, duty_cycle=0)
+    # LED setup for QT Py M0:
+    # led = pwmio.PWMOut(board.SCK, frequency=5000, duty_cycle=0)
+
+    while True:
+        for i in range(100):
+            # PWM LED up and down
+            if i < 50:
+                led.duty_cycle = int(i * 2 * 65535 / 100)  # Up
+            else:
+                led.duty_cycle = 65535 - int((i - 50) * 2 * 65535 / 100)  # Down
+            time.sleep(0.01)
+