Added code for Lab 9

Lab09/MicroPython/Code/pwm/pwm_fade.py

@@ -0,0 +1,26 @@
+# Example using PWM to fade an LED.
+
+import time
+import machine
+from machine import Pin, PWM
+
+
+# Construct PWM object, with LED on Pin(25).
+pwm = PWM(Pin(15))
+
+# Set the PWM frequency.
+pwm.freq(1000)
+
+# Fade the LED in and out a few times.
+duty = 0
+direction = 1
+for _ in range(8 * 256):
+    duty += direction
+    if duty > 255:
+        duty = 255
+        direction = -1
+    elif duty < 0:
+        duty = 0
+        direction = 1
+    pwm.duty_u16(duty * duty)
+    time.sleep(0.005)