Output multiplexer circuit for input/output block
US5811985A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 31, 1997 |
| Grant date | Sep 22, 1998 |
| Priority date | — |
| Expiry date | Jan 31, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K19/17704
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A input/output circuit (IOB) within an integrated circuit (IC) device, the output signal driving circuitry of the input/output device contains a dedicated multiplexer on the output path wherein a first and second output signal can be time multiplexed on a single output pad. The multiplexer can also be configured to perform as a high speed gate to realize AND, OR, XOR, and XNOR functions. Within an input/output circuit of a programmable integrated circuit, the system provides a dedicated multiplexer that can select between one of two output signals for sending over the single output pad of the IC device. In lieu of using a programmable memory cell as the select control for the dedicated multiplexer, the system allows a number of lines, including an output clock signal, to be the select control. By using the output clock as the select control, the data signals can be effectively time multiplexed over a single output pad and referenced by the output clock. This output multiplexer circuit effectively doubles the number of output signals the IC device can provide with a given number of output pads. The dedicated multiplexer when configured as a high speed gate is useful for generating v…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.