Integrated circuit microcontroller with on-chip memory and external bus interface and programmable mechanism for securing the contents of on-chip memory
US5251304A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 28, 1990 |
| Grant date | Oct 5, 1993 |
| Priority date | — |
| Expiry date | Sep 28, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F12/1433
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A data processor with memory within a single integrated circuit package provides a programmable "secure mode" of operation to selectively restrict access and protect information stored in its memory. The secure mode of operation is included in addition to a "single chip mode" wherein the data processor accesses both data and instructions strictly from within the single integrated circuit package. An "expanded mode" of operation also exists wherein the data processor may access either internal or external memory for both instructions and data. The secure mode of operation restricts accesses of instructions to memory contained within the single integrated circuit while allowing data accesses to memory either internal or external to the integrated circuit. The secure mode is accomplished by selectively isolating internal data/instruction bus transfer activity from an external data/instruction bus.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.