How it Works

How the led_blink_2x Script Works

These statements repeat indefinitely inside the while True loop:

• The pin13.write_digital(1) method call sets a high signal through P13, turning on the green light.  
• The pin14.write_digital(1) call does the same thing but through P14, turning on the yellow light.
• The sleep(500) call makes the script pause for 0.5 s.  The lights stay on during this time.
• The pin13.write_digital(0) and pin14_write_digital(0) calls set P13 and P14 low, turning the LED lights off.
• The sleep(500) call makes the script pause for another 0.5 s, during which time, the lights stay off.

Try This: On/Off Alternating

Changing from simultaneous to alternating blinks is pretty simple.  All you have to do is change the state argument in two of the pin14.write_digital calls.

• Change the line 1 comment and the project name field to led_blink_2x_alternating.  
• Change the first pin14.write_digital call’s state argument from 1 to 0.
• Change the second pin14.write_digital call’s state argument from 0 to1.
• Click Save and then click Send to micro:bit.
• Verify that only one light is on at a time, and that they alternate.