Embedded system guiding method and device

Abstract

The invention discloses a booting method for an embedded system based on a memory, comprising: executing a startup code once; scanning a sequence used to indicate a data reading position, and reading data in the memory from the position indicated in the sequence; judging Whether the read data is a valid secondary startup code, if valid, call or execute the secondary startup code to guide the system code to run; if invalid, return and read from the next position indicated in the sequence data. The present invention can overcome the shortcoming that the BOOT ROM needs to be changed according to the new type of flash, and is not restricted by the new flash type, which is beneficial to the upgrade and maintenance of the embedded system; avoids the cumbersome judgment of the flash ID number, and can adapt to any Nand flash Interface flash; can effectively guarantee the normal startup of the system, and the redundant backup mechanism is simple and reliable.

Description

[0001] Technology Territory [0002] The present invention relates to a boot method of a computer system, in particular to a boot method and device of an embedded system based on a memory, and is especially suitable for booting of a NAND flash embedded system. Background technique [0003] Embedded system refers to a device or system that is designed for specific applications, performs special functions, and is controlled by an internal computer. [0004] Currently, embedded systems using flash memory as storage media are widely used. Flash memory is a non-volatile memory, divided into NOR flash and Nand flash. Nand flash can be used as a program memory for storing system codes and as a data memory for storing user data. Using Nand flash can not only simplify the system structure, but also help improve the stability of the system. Reference figure 1 As shown, today’s mainstream Nand flash embedded system usually consists of the following main parts: Microcontroller (MCU) 101, RAM ...

AI Technical Summary

Problems solved by technology

[0007] However, the above-mentioned boot process will cause the following problems: if the system guides a new model of Nand flash, it is necessary to add the ID number of the new model flash and the table entry of its structural characteristics comparison table in the list of ROM, so that the boot code cannot be modified without modification. New models of Nand flash are supported under certain circumstances; the boot code usually needs to exist in a relatively fixed space such as ROM, and the continuous addition of new models of flash support items will not be conducive to the upgrade of the embedded system, and frequent modifications are not conducive to the system The length and reading method of different Nandflash ID numbers are also different, which makes the identification of the boot code very cumbersome and inconvenient for system maintenance; with the increasing number of flash models, the part of the boot code to identify the ID number will become more and more complicated. The bigger it gets, the more storage space it takes up

Although this method does not care about the internal data structures of various Nand flashes, this method has obvious limitations: it is not applicable to all types of flash; it cannot be guaranteed to start normally when the first page data is wrong; and , the startup code can only be limited to the first page, and it is not easy to expand

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