Method for interfacing boundary-scan circuitry with linearized impedance control type output drivers
US5872796A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 30, 1997 |
| Grant date | Feb 16, 1999 |
| Priority date | — |
| Expiry date | Jun 30, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R31/318541
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method for coupling a linear impedance control (LIC) type output driver to IEEE 1149.1 boundary scan circuitry includes entering a boundary scan load mode to load a test pattern into a chain of boundary scan registers (BSRs). The test pattern includes values corresponding to output enable and data signals according to the IEEE 1149.1 standard. Then these data and output enable signals from the BSRs are converted into test "q.sub.-- up" and "q.sub.-- dn" signals meeting the requirements of the LIC driver. These test "q.sub.-- up" and "q.sub.-- dn" signals are selectively provided to the LIC driver during boundary scan testing of the LIC driver. In a further refinement, the method enters a boundary scan capture mode to capture the response (i.e., the functional q.sub.-- up and q.sub.-- dn signals) of the circuit under test to input test patterns shifted into the BSRs. The functional q.sub.-- up and q.sub.-- dn signals are converted into response data and oe signals complying with the IEEE 1149.1 specification, which are then captured in the BSRs. Thus, this method allows the widely used IEEE 1149.1 boundary scan standard to be used with LIC drivers. The resulting compatibility simp…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.