Nowadays there are a lot of things done by machines. Often these machines make use of communication channels to receive controlling information from human persons or other machines. Also between subparts of a machine there is often a communication channel. There are several kinds of communication channels varying from a simple electrical wire to complicated networks.udSince the computer is increasingly used to receive information and to control machines (devices) it is important to think about what is the best kind of communication channel to use between them. In former days the serial port was most used, now there are a lot of technologies for the communication between computer and device such as IEEE1394 (FireWire), IrDa (Infrared), Bluetooth, CAN, I2C and USB. Of course each technology has its own advantages and disadvantages regarding to specific properties. If we want to use a communication channel between computer and device important to find out what are the necessary properties for the desired application. As an example of different kind of properties there are: data transfer/second; robustness; prize; distance between device(s) and computer; topology; delay time; amount of data/transfer; constancy of data/time.udGoal of this project is to investigate some of the specifications of the delay time of data transfers in systems with the USB protocol. Unfortunately it is not possible to investigate all the parameters; therefore we only look at the most interesting of them. When the average and worst-case delay time are known possible to determine if the protocol is feasible for certain real-time applications. This explains the title of this report: "Adequacy of the Universal Serial Bus for real-time systems". To clear up the term real-time and to explain why we want to test USB the remaining part of this chapter is about these subjects.
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