The Universal Serial Bus (USB) (1)

The USB Interface described elsewhere in this issue demonstrates that the USB may be used for DIY projects related to measurement and control. But how does one develop USB compatible peripherals, which conditions should be satisfied, and where can the necessary information be found?The USB is a serial bus system designed for connection to and addressing of several peripheral devices. USB is considerably more complex than RS232, but also much faster at up to 1.5 Mbit/s (for low-speed devices) or 12 Mbit/s (for full-speed devices). Furthermore, the designers of the USB have paid a lot of attention to simplicity and ease of use. It is fair to say that the concept of Plug and Play, for the first time, actually applies to the USB, which allows devices to be connected and automatically initialised with the PC switched on or off. With USB, you don’t have to grapple with interrupt conflicts, wrong addresses and missing drivers.