Method, device and intelligent card for accessing data

Abstract

The invention discloses a method, a device and an intelligent card for accessing data, which realize data access of the virtual memory space of the intelligent card without using a memory management unit (MMU). The method comprises the following steps of: receiving a data access command, and determining a command type and a target address to be accessed according to the data access command; when the target address is determined to be a virtual address and the virtual address is in a set virtual address range, determining the offset amount of the target address in an page index of a non-volatile memory; and performing corresponding data access operation in storage space corresponding to the offset amount, wherein the data access operation corresponds to the determined command type. By adopting the technical scheme, the data access of the virtual memory space of the intelligent card is realized without using the MMU; the difficulty in performing the data access on the virtual memory space of the intelligent card is reduced; the method can be used for the intelligent cards without an MMU function; therefore, the universality is improved.

Description

technical field [0001] The invention relates to the technical field of smart cards, in particular to a method and device for accessing data and a smart card. Background technique [0002] In terms of hardware structure, smart cards such as figure 1 As shown, including CPU (Central Processing Unit, central processing unit), RAM (Random Access Memory, random access memory), EEPROM (Electrically Erasable Programmable Read-Only Memory, electrically erasable programmable read-only memory) and ROM (Read-Only Memory, read-only memory) composition. However, with the development of smart card hardware technology, EEPROM is gradually replaced by non-volatile NorFlash flash memory with low cost and large storage space. NandFlash is used as the auxiliary memory of NorFlash. Therefore, the current smart card structure is as follows: figure 2 As shown, it consists of CPU, RAM, NorFlash and NandFlash. [0003] The RAM on the smart card is used to store the data used for the running of ...

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Problems solved by technology

[0008] Although the data access to the virtual memory space of the smart card is realized by the above method, it has the following defects: this method is only applicable to the smart card with the MMU function, and the smart card that cannot support the MMU function cannot use the above method to access the virtual memory space of the smart card. memory space for data access, and most of the smart cards do not have the function of MMU at present, the versatility is low, and the scope of promotion is relatively narrow, and the prior art does not provide how to access the virtual space in the smart card that does not have the MMU function. method

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