Programmable input/output buffer circuit with test capability
US5221865A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 21, 1991 |
| Grant date | Jun 22, 1993 |
| Priority date | — |
| Expiry date | Jun 21, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K19/018585
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An integrated circuit having system logic with programmable elements, decoding logic coupled to the programmable elements for addressing the programmable elements and a plurality of input/output buffer circuits for passing signals between the system logic and the exterior of the integrated circuit through input/output terminals is disclosed. Each input/output buffer circuit comprises an output driver stage having an output terminal connected to an input/output terminal; and a plurality of cells, each cell having a multiplexer, a flip-flop connected to an output terminal of the first multiplexer for storing a signal from the first multiplexer, a latch connected to an output terminal of the first storing means for storing a signal from the first storing means, and a second multiplexer connected to an output terminal of the latch. The cells connected to each other and cells of other input/output buffer circuits from an output terminal of the flip-flop of one cell to a first input terminal of a first multiplexer of another cell for serial scanning of signals through the cells to test the system logic. Control lines are connected to the output terminals of the latch of the cells and to …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.