METHOD AND CONTROL DEVICE FOR LAUNCH-OFF-SHIFT AT-SPEED SCAN TESTING

摘要

The invention provides a method for launch-off-shift at-speed scan testing for at least two scan chains of an integrated circuit comprises iteratively shifting set values for functional elements of a first one of the scan chains clocked with a shift clock, iteratively shifting set values for functional elements of a second one of the scan chains clocked with the shift clock, launching an at-speed scan test clocked with a functional clock for the first one of the scan chains at a last shift cycle of the first one of the scan chains, delaying the last shift cycle for the second one of the scan chains for a predetermined time span, launching an at-speed scan test clocked with a functional clock for the second one of the scan chains at the last shift cycle of the second one of the scan chains, capturing the sample values of the functional elements of the first and second scan chains after the last shift cycle of the scan chains.

主权项

1. A method for launch-off-shift at-speed scan testing for at least two scan chains of an integrated circuit, comprising:
iteratively shifting set values for functional elements of a first one of the scan chains clocked with a shift clock; iteratively shifting set values for functional elements of a second one of the scan chains clocked with the shift clock; launching an at-speed scan test clocked with a functional clock for the first one of the scan chains at a last shift cycle of the first one of the scan chains; delaying the last shift cycle for the second one of the scan chains for a predetermined time span; launching an at-speed scan test clocked with the functional clock for the second one of the scan chains at the last shift cycle of the second one of the scan chains; capturing the sample values of the functional elements of the first one of the scan chains after the last shift cycle of the first one of the scan chains; and capturing the sample values of the functional elements of the second one of the scan chains after the last shift cycle of the second one of the scan chains.