In the "Quick reference for the WiPy", under "Pins and GPIO" the use of GP2 and GP1 is not good, because they are connected to UART0_RX and UART_TX on the expansionboard.
I was trying the example with GP2, and my communication via USB stopped.
Be carefull not to use GP1 and GP2, if you also uses the usb connection.
Quick reference for the WiPy
Quick reference for the WiPy
Yes Frida is my watchdog!