The present invention provides a Programmable Logic Device (PLD) incorporating a two-input multiplexer for providing a Cascade Logic output and having a Cascade Logic input coupled to a select line. A two-input multiplexer provides the desired configurable Cascade Logic function, and an initialization...http://www.google.com.hk/patents/US6864714?utm_source=gb-gplus-share專利 US6864714 - PLDs providing reduced delays in cascade chain circuits
