1149.6 std

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Abstract:
This standard augments IEEE Std 1149.1 to improve the ability for testing differential
and/or ac-coupled interconnections between integrated circuits on circuit boards and systems

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1. Overview
1.1 Scope
This standard defines extensions to IEEE Std 1149.1 to standardize the Boundary-Scan structures and methods required to ensure simple, robust, and minimally intrusive Boundary-Scan testing of advanced digital networks.


1.2 Organization of the standard

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1.3 Context

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1.4 Objectives
The objective of this standard is to provide design guidance for testability circuitry added to an IC in addition to testability provisions specified by IEEE Std 1149.1, such that when such an IC contains differential signaling and/or is AC-coupled with other ICs compliant to this standard, board and system level tests can be readily and accurately conducted, with enhanced defect coverage

3. Definitions and acronyms
3.1 Definitions
3.1.1 AC-coupling
The use of series capacitance in a signal path.
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3.1.2 AC pins: Advanced I/O
pins that require a time-varying (AC) signal to permit testing of their interconnections.

3.1.3 AC test mode:
A test mode that enables Boundary-Scan testing between AC pins that are AC-coupled or DC-coupled.

3.1.4 AC Test Signal:
A signal generated by the AC test mode that is used to modulate static test data into a
time-varying signal that can pass through AC-coupling. A test receiver and detector is used to recover the static test data value from within the time-varying signal.