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An Update on 1149.6 Maintenance Work. Bill Eklow, Cisco Systems, Inc. Background. 1149.6 Approved in March, 2003 Extension to 1149.1 for “Advanced Digital Networks” Targets AC-Coupled AND Differential Nets Initially used by telecom companies, use is spreading with high speed serdes
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An Update on 1149.6 Maintenance Work Bill Eklow, Cisco Systems, Inc.
Background • 1149.6 Approved in March, 2003 • Extension to 1149.1 for “Advanced Digital Networks” • Targets AC-Coupled AND Differential Nets • Initially used by telecom companies, use is spreading with high speed serdes • Now due for 5 year tuneup
Update-DR TX RX Capture-DR Background: Effect of Signal Decay ? Vref
Pass X Background: 1149.1 Analog model SA1 • Reduced Fault Coverage • Limited Diagnostic Capability
Output Boundary Structures • TAP logic to create AC Test Signal Based on Fig. 51, IEEE 1149.6 Std.
Observations from the first 5 years • Luck – group hit technology inflection point • Test receiver design difficult • Timing was not/is not an issue • People got it on AC-coupling, not differential • Use is picking up due to AC-coupling on more “commercial” protocols • Issues with “DC-coupled” nets
Conclusion • Standard performed well over first 5 yrs. Only minor changes required. • Design practices/requirements need to be better explained • Use of dot 6 for DC coupled nets is a hard sell. • Major contribution of next revision will be Initialize