Flash ROM sharing between processor and microcontroller during booting and handling warm-booting events
US6154838A · kind A · utility
Inventors
Key dates
| Filing date | Oct 5, 1998 |
| Grant date | Nov 28, 2000 |
| Priority date | — |
| Expiry date | Oct 5, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F13/1605
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A computer system having a processor, a microcontroller, a flash ROM is provided with an address remapper for handling warm-boot events, 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 power is initially provided to the system. After the flash ROM boots up and checks the integrity of the flash ROM and updates the content of the flash ROM with valid firmware 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 copies or shadows one or more portions of the flash ROM BIOS into a main memory array. After the shadow operation, the processor sets a remap bit to indicate that the ROM BIOS content has been copied into the main memory array. The setting of the remap bit enables the remapper to deflect accesses to the flash ROM. The restarting of the clock signal to the microcontroller to switch the ownership of the flash ROM back to the microcontroller. In the even…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.