Programmable logic device configurable input/output cell
US4896296A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 23, 1988 |
| Grant date | Jan 23, 1990 |
| Priority date | — |
| Expiry date | Dec 23, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K19/1778
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An in-system programmable logic device is disclosed which may be configured or reconfigured while installed in a user's system. The disclosed device employs non-volatile memory cells such as floating gate transistors as the programmable elements, and hence the device retains a particular programmed logic configuration virtually indefinitely during a powered-down state. The device is operable in a normal state and in several utility states for reconfiguring the device. The device state is controlled by an internal state machine which executes several state equations whose variables are the logic levels driving two dedicated pins and the present device state. One device pin receives serial input data which loads a shift register latch. The contents of the latch are employed to select a particular row of the cells to be programmed and the logic level to which the selected cells are to be programmed. The device normal inputs and outputs are isolated from the device during the utility states, so that the user's system does not affect the device operation during the utility states. A voltage multiplier circuit is included to generate the high voltage level necessary to program the floati…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.