TL;DR: In this article, a bank of switches coupled to a multitapped delay line for selecting delay line signals for setting the basic clock timing is used to provide an uninterrupted succession of clock pulses.
Abstract: A microprogrammed commercial instruction processor in a data processing system includes a bank of switches coupled to a multitapped delay line for selecting delay line signals for setting the basic clock timing. Another of the switches when activated conditions the commercial instruction processor so that when it is reset a special clock setting firmware loop is entered. The loop provides an uninterrupted succession of clock pulses which allows one to adjust the basic clock timing within specification.