A Micro-Controller interface for Control-L devices
Tony Dale
Department of Computer Science
University of Canterbury
Abstract
The Sony Corporation's Control-L protocol is proprietry but publicly available. Many video devices can use this protocol, and thus provide semi-professional video editing facilities, depending on the capabilities of the video device (usually a camera or video cassette recorder).
Implementing the Control-L protocol presents some challenges because although it is based on 9600 baud asynchronous characters, start bits for each character are provided from a central source. This introduces strict timing constraints for a controlling device to comply with which are beyond the capabilities of the hardware and operating systems of many available computer systems, especially multi-user systems.
his article describes a ``freeware'' implementation of the Control-L protocol on the MIT Miniboard. A simple asynchronous protocol is used to communicate with a host computer, via an RS232 link.