Scan Synthesis for One-Hot Signals

Tri-state buses and pass transistor logic are used in many complex applications to achieve high performance and small area. Such circuits often contain logic requiring one-hot signals. In a scan-based design, one-hot values on these signals may not be maintained during the scan-in and scan-out operations. Also, the presence of faults, the existence of don’t care conditions and the use of random patterns for testing the circuit in a scan or BIST environment may lead to non-one-hot values on these onehot signals, resulting in abnormal circuit behavior and possible circuit damage. In this paper, we present new techniques for synthesizing scan-based designs so that onehot values are maintained on the one-hot signals during all modes of operation. One of our synthesis techniques often generates designs with no area overhead — the designs are smaller than those that do not ensure safe scan operation. In addition, we propose a scan path design that has no performance overhead during the ...

• Type: Conference
• Year: 1997
• Where: ITC
• Authors: Subhasish Mitra, LaNae J. Avra, Edward J. McCluskey
• Keywords: Hardware, ITC 1997, One-hot Signals, Safe Scan Operations, Scan-based Designs