Boundary-scan register cell with bypass circuit
US6314539A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 21, 1998 |
| Grant date | Nov 6, 2001 |
| Priority date | — |
| Expiry date | Oct 21, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R31/318541
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A Boundary-Scan register (BSR) cell including a bypass circuit for selectively routing data signals around the data shift register of the BSR cell so that the BSR cell can be effectively removed from a BSR chain during Boundary-Scan Test procedures involving IEEE Standard 1149.1 compliant integrated circuits. In one embodiment, the BSR cell includes a bypass MUX having a first input terminal connected to a test data input (TDI) terminal of the BSR cell, a second input terminal connected to an output terminal of the shift register, and an output terminal connected to the test data output (TDO) terminal. The BSR cell operates in a "normal" mode (i.e., included in the BSR chain) when the bypass MUX is controlled to pass data signals output from the shift register to the TDO terminal. In contrast, the BSR cell is selectively bypassed (i.e., removed from the BSR chain) when the bypass MUX is controlled to pass the TDI signal to the TDO terminal. The BSR cell also includes mode control MUX having a first input terminal connected to receive a MODE signal generated by a Boundary-Scan TAP controller, a second input terminal connected to an OFF (disable) signal source, and an output terminal…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.