Method for ensuring mutual exclusivity of selected signals during application of test patterns
US6081913A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 3, 1997 |
| Grant date | Jun 27, 2000 |
| Priority date | — |
| Expiry date | Jun 3, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R31/318558
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method for controlling a gating circuit of an electronic system incorporating a scan architecture complying with IEEE Standard 1149.1 such that the gating circuit applies mutually exclusive signals to, for example, a decoded multiplexer. The gating circuit receives input signals from flip-flops that are part of a scan chain, is selectively controllable by a control signal to transmit predetermined mutually exclusive signals to the select inputs of the multiplexer during a scan mode. Alternatively, the gating circuit is controllable by the control signal to pass the input signals to the multiplexer in a normal operation or test mode. A mutual exclusivity circuit is provided to generate the control signal. During the scan mode, the control signal is generated at a first logic level such that the gating circuit transmits the predetermined mutually exclusive signals to the multiplexer while test values are being scanned into the flip-flops. Upon transition from the scan mode to the normal operation mode, the control signal is changed to a second logic level for a predetermined time period, and then changed back to the first logic level. When the control signal is at the second logic …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.