General Purpose Clock
The Raspberry Pi has two hardware clocks available for the end user (the others are reserved or used by the system). One of these user accessible clocks is used for Pulse Width Modulation (PWM), which is the subject of Chapter 7. The other is known as GPCLK0 in the Broadcom vernacular.
To assist in our exploration, the piclk command has been provided as part of this book’s included software. This saves us from writing programs to conduct experiments and remains as a tool for you to use.
The piclk Command
If you installed the book’s provided software, the piclk command should be immediately available as follows: ...