A Multichannel Event Timer for Real-Time Laboratory Computer Systems

In this paper we describe an event timer which was designed to be used in a neurophysiological laboratory. The timer is used with an LSI 11/03 computer and interfaces with the computer through a standard Digital Equipment Corporation DRV 11 interface board. The time of occurrence of pulses on up to 15 different input lines can be recorded with an accuracy determined by the time base of the timer, which can be varied from 1 to 5000 gs. In order to record events that occur simultaneously on different channels or in very rapid succession, we employ a first-in, first-out (FIFO) register as a buffer. An input scanner allows one timer to be used for timing events that occur on several input channels. This device may be useful in other applicatoins in which the time of occurrence of multiple events needs to be accurately timed.