Method and system for protecting DRAM stored data of embedded system software

Abstract

A method for protecting DRAM (Dynamic Random Access Memory) stored data of embedded system software can ensure security of stored data when the system software undergoes an exception. According to the method, an MCU is used to take charge of hardware resetting of an entire embedded system, to monitor software resetting of the embedded system, and to communicate with a main system CPU of the embedded system, so as to learn a current working status of the embedded system; when a system reset signal is detected, the MCU takes over control of a DRAM, and sending a self-refresh command to the DRAM, to enable the DRAM to enter a self-refresh mode, so as to ensure security of DRAM data during an entire resetting period of the embedded system; and after completion of resetting of the embedded system and before a boot program of the embedded system runs and prepares to initialize the DRAM, the MCU sends a quit self-refresh command to the DRAM, and releases and returns the control of the DRAM to the main system CPU, so that after the main CPU takes over the DRAM, the data stored in the DRAM is still valid.

Description

Technical field [0001] The invention relates to a method and system for protecting DRAM (Dynamic Random Access Memory) storage data when the software of an embedded system is abnormal. Background technique [0002] Many embedded applications need to save user data, field data, various configuration information, parameters, program running status, etc., so that the scene can be easily restored after the system restarts, or the previously saved data can be reloaded. The safe method is to save the data to various non-volatile storage media. But before the data is safely saved to the non-volatile storage medium, there are still various risks and possible errors: program deadlock, system software error, external interference, other software abnormalities, etc. When these abnormalities occur in the system software, most systems will use the watchdog function to reset the system in order to restart the system. In a few cases, a hardware reset must be initiated. However, when the syste...

AI Technical Summary

Problems solved by technology

[0004] 1. Use static SRAM as system memory and data storage and use battery backup. The advantage of this method is that all data can be temporarily saved after the system is powered off or shut down, and the data will not be lost when the system is reset; but this method The biggest disadvantage of SRAM is: the capacity of SRAM is limited, and there is a lack of large-capacity and low-cost SRAM in the market. If a large-capacity SRAM is used, the system cost will increase significantly, and it is difficult to meet the cost requirements of ordinary products.

This method seems to protect the data well, but it still has a fatal shortcoming: before the data is safely saved to the non-volatile memory, various software deadlocks, software errors, external interference, etc. Cause software abnormality, once these software abnormalities occur, it is impossible for the system software to safely back up the data to the non-volatile memory, then manual reset or software reset is required to restart the system

However, DRAM data cannot be guaranteed to be safe during system restart

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