Input/Output

There are as many choices for I/O devices as there are embedded systems. Your application will determine what type of I/O devices you need. Fortunately, a veritable army of Linux programmers have had years to develop and refine the necessary device drivers to support nearly any hardware imaginable. Probably the best example can be seen in the large number of network controllers supported. Chances are good that if a peripheral function exists on silicon, someone has already written the supporting code. Significantly, this includes the component manufacturers themselves, as Linux has become a major force in the marketplace in recent years.

If your requirements are very simple (for example, a few LEDs and simple switches), chances are good that you can use a low-cost parallel port by slightly modifying the drivers. Some very simple systems require no I/O at all. While a device with no I/O probably wouldn’t be very useful, such devices are possible, since Linux, unlike Windows, has no set hardware requirements. Therefore, the choice is entirely up to you.