A 3-axis accelerometer senses the orientation of the phone and changes the screen accordingly, allowing the user to easily switch between portrait and landscape mode. Photo browsing, web browsing, and music playing support both upright and left or right widescreen orientations. Unlike the iPad, the iPhone does not rotate the screen when turned upside-down, with the Home button above the screen, unless the running program has been specifically designed to do so. The 3.0 update added landscape support for still other applications, such as email, and introduced shaking the unit as a form of input (generally for undo functionality). The accelerometer can also be used to control third-party apps, notably games. It is also used for fitness tracking purposes, primarily as a pedometer. Starting with the iPhone 5S, this functionality was included in the M7 Motion coprocessor and subsequent revisions of the embedded chip.