The Realization Of Start Up From NAND Base On Independent CPU

This topic mainly research the independent CPU start-up from NAND technology.The current application of the CPU in embedded direction will provide a variety of start-up mode, such as SPI ROM, NAND FLASH, NOR FLASH etc.. With the development of technology, main status is formed, PC platform base on SPI ROM startup, embedded platform base on NAND FLASH start-up.The CPU is involved in the domestic high performance CPU for embedded market, can be used in consumer electronics, industrial control, network routing etc.. CPU hardware provides a NAND controller, and provides the ability to boot from external NAND FLASH, software has not to realize this function. CPU can work, first of all to enable it to be started up normally, in here is to realize the function that boot from external NAND in FLASH software, which occupy the mainstream in the embedded market. From the software point of view is that CPU can start up normally and work under BIOS, can boot kernel and operating system normally. Because CPU is involved in this thesis does not reserve enough space for NAND controller in chip design, causing the the internal RAM which used to start up is relatively small, not enough to complete the start up function, so this paper presents the method to lock the level two of Cache as the core idea, and increased level of Bootloader, through two levels of Bootloader to realize the start up function.The realization of this function can not only improve the related software function, and fit the demand of downstream manufacturers, can provide a stable work environment to the relevant enterprise software developers and the community of developers, can promote the popularization and application of this CPU in the embedded market, this application independent CPU in the market have positive significance. At present the domestic development board based on the CPU has been applied already.