Integrated circuit microprocessor with programmable memory access interface types
US5727005A · kind A · utility
Inventors
Key dates
| Filing date | Aug 31, 1994 |
| Grant date | Mar 10, 1998 |
| Priority date | — |
| Expiry date | Aug 31, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F13/4243
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An integrated circuit microprocessor (30) accesses external memory using internally-generated control signals having programmable memory access interface types. A register (61), associated with a memory region, stores an encoded value. During an access to that memory region, a decoder (63) decodes the encoded value to provide a decoded signal. If the decoded signal is in a legal state, then an access controller (64) activates external control signals with timing corresponding to the legal state. If the decoded signal is in a reserved state, then the access controller (64) prevents the access from taking place by keeping the external control signals inactive, preventing software errors from resulting in illegal accesses. For one legal memory access type, the early synchronous output enable access type, the access controller (64) activates an output enable signal at a clock transition but doesn't latch the corresponding data until the next transition, allowing efficient accesses to memory devices with slower memory cores.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.