Using specialized memory

Embedded systems often provide access to their peripheral devices over specific ranges of memory addresses. When a program accesses an address in such a region, it does not read or write a value in memory. Instead, data is sent to a device or read from a device mapped to this address.

This technique is commonly named MMIO (short for memory-mapped input/output). In this recipe, we will learn how to access peripheral devices of the Raspberry PI using MMIO from userspace Linux applications.

How to do it...

The Raspberry PI has a number of peripheral devices that are accessible over MMIO. To demonstrate how MMIO works, our application will access the system timer:

1. In your working ~/test directory...