Abstract: A method and system are provided for improved communication between devices. A first device having an associated first clock rate may communicate with a second device having an associated second clock rate. Particular periods of time are determined during which metastability may occur as a result of differences between the first clock rate and the second clock rate. Data transmitted from the first device to the second device is continually processed. During those particular periods of time when metastability may occur, the processed data is input into the second device. During all other periods of time, the data is input directly into the second device.

Abstract: Disclosed is a test method and system for boundary testing a circuit network. The network, made up of individual integrated circuit chips mounted on a printed circuit card or board, has at least one integrated circuit that is testable by IEEE 1149.1 Standard boundary testing, and at least one second integrated circuit that is testable by Level Sensitive Scan Design boundary testing but not by IEEE 1149.1 Standard boundary testing. The test system has a test access port interface with a test access port controller with Test Clock, Test Data In, Test Data Out, Test Mode Select, and Test Reset I/O. The test access port also has an instruction register, a bypass register, a test clock generator, and a Level Sensitive Scan Device boundary scan register.