hello-audio: emit 1KHz square wave on MB2 speaker

Bart Massey 2023

The 1KHz square wave is the "hello world" of audio programs.

While button A on the MB2 is pressed, the program toggles a GPIO line connected to the MicroBit v2 speaker every 500µs: this causes the MB2 to emit an annoying 1KHz square wave.

License

This work is licensed under the "MIT License". Please see the file LICENSE.txt in this distribution for license terms.