Catch Ctrl-C and unlock I2C bus before exiting

Author: hjw

CircuitPython_Essentials/CircuitPython_I2C_Scan.py

@@ -1,15 +1,24 @@
 # CircuitPython demo - I2C scan
+# 
+# If you run this and it seems to hang, try manually unlocking
+# your I2C bus from the REPL with
+# ` >>> import board `
+# ` >>> board.I2C().unlock() `
 
 import time
-
 import board
 
 i2c = board.I2C()
 
 while not i2c.try_lock():
     pass
 
+try:
+
 while True:
     print("I2C addresses found:", [hex(device_address)
                                    for device_address in i2c.scan()])
     time.sleep(2)
+
+finally:  # unlock the i2c bus when ctrl-c'ing out of the loop
+    i2c.unlock()