Script and Tests

Script: button_led_blink_with_plot

• Right-click button_led_blink_with_plot.hex (below), and choose Save Link As…to download.

button_led_blink_with_plot.hex

• Click the micro:bit Python Editor’s Open button, then select and open button_led_blink_with_plot.hex. 
• Click Send to micro:bit.  
• Click the three vertical dots  ⋮  by the Send to micro:bit button, and select Disconnect.
• Start the CYBERscope:
  • In a different browser tab, go to cyberscope.parallax.com.  
  • Click the CYBERscope’s Connect button.
  • In the serial port dialog, select the port with mbed in its name, and then click Connect. 

Tests

• Wait until the plotted dots reach (or wrap back around to) somewhere in the 2k to 4k range.
• Press and hold the pushbutton for about six blinks.
• Verify that your plot resembles this.  

NOTE: Before the first pushbutton press, you might notice the red Ch2 voltage trace is plotting irregularly in the 0.5 to 1.5 V range.  That’s because the LED pin is a floating input that has not been set to low or high by pin13.write_digital(0) or pin13.write_digital(1).

Also verify the following:

• While the button is not held down:
  • The black ch0 trace connected to the pushbutton should repeatedly plot points close to 0 V along the bottom of the plot area.  
  • The red ch2 trace connected to the LED should also plot points close to 0 V along the bottom of the plot.  
• While the button is held down:
  • The black ch0 trace should plot points at around 3.3 V.
  • The red ch2 trace should plot the on signals in the 2.5 to 3.3 V neighborhood, and off signals at 0 V, should continue to repeat while the button is pressed and held down.
• In the CYBERscope, click Disconnect.