Added code for Lab 9

Lab09/MicroPython/Code/pwm/pwm_fade4.py

@@ -0,0 +1,37 @@
+# Example using PWM to fade an LED  on pin GP16.
+
+import time
+import machine
+from machine import Pin, PWM
+
+def pwmFade(fadeTime):
+    # 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(fadeTime)
+    return 0
+
+
+# Construct PWM object, with LED on Pin(25).
+pwm = PWM(Pin(16))
+
+# Set the PWM frequency.
+pwm.freq(1000)
+
+print("Fade time is set to .001")
+# Fade the LED in and out a few times.
+pwmFade(.001)
+
+print("Fade time is set to .01")
+# Fade the LED in and out a few times.
+pwmFade(.01)
+