Flash ROM sharing between a processor and a controller
US5794054A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 19, 1996 |
| Grant date | Aug 11, 1998 |
| Priority date | — |
| Expiry date | Jul 19, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F13/1605
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
In accordance with the invention, a computer system is provided with a processor, a flash ROM, a microcontroller and an arbiter for selectively assigning the ownership of the flash ROM to either the microprocessor or the microcontroller. The arbiter assigns the flash ROM initially to the microcontroller when it boots up. After checking the integrity of the flash ROM and updating the content of the flash ROM with valid software if necessary, the microcontroller releases the flash ROM to the microprocessor to enable the computer system to proceed with the normal boot-up process. In this process, various system self tests are performed. Next, the microprocessor shadows one or more portions of the flash ROM BIOS into a main memory array. After the processor successfully boots up, the processor releases the flash ROM back to the microcontroller by writing a command to a mailbox register in the arbiter which places the microcontroller in an idle mode and by restarting the clock generator of the microcontroller. The restarting of the clock signal to the microcontroller to switch the ownership of the flash ROM back to the microcontroller. In the event that the microprocessor needs to regai…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.