Analyzer for capturing elapsed time values if predetermined conditions

Abstract

A time-stamp timer for a GPIB system including a counter for providing elapsed time values and capture logic for capturing GPIB samples upon predetermined conditions and for capturing a maximum elapsed time value upon rollover of the counter. The GPIB samples and time values are preferably captured into a first-in, first-out (FIFO) buffer. The capture logic preferably resets the counter after GPIB signals are captured due to the predetermined conditions, so that each time value represents an elapsed time between GPIB samples. If the counter reaches a rollover condition, the capture logic causes another capture into the buffer for capturing the maximum elapsed time value. Thus, any consecutive maximum elapsed time values are summed with a final elapsed time value to determine elapsed time between any two valid GPIB captures. In one embodiment, marker logic marks each first occurrence of the maximum elapsed time value to notify software of timer rollover.