Looking for breakthrough ideas for innovation challenges? Try Patsnap Eureka!

File access method and device of SD (Secure Digital) card

A file reading and file technology, applied in the direction of input/output to record carrier, instrument, electrical digital data processing, etc., can solve the problems of discontinuity, resource occupation, memory address discontinuity, etc., to reduce resource occupation and improve speed Effect

Active Publication Date: 2010-11-03
中星智能系统技术有限公司
View PDF3 Cites 12 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The file access of the SD card is usually realized by DMA (direct memory access). It is known that a DMA transfer can only be performed for data that is physically continuously stored. However, in practice, the memory address corresponding to a file may It is discontinuous (such as the CPU memory address obtained by MMU mapping), or the cluster corresponding to a file in the SD card FAT table is physically discontinuous. In this case, it can only be transferred by multiple DMA To complete a file access process
Obviously, it seriously affects the validity of data access, and because a DMA transfer is completed, the CPU will be notified through an interrupt, and multiple transfers will interrupt the notification multiple times, and it also seriously occupies CPU resources.

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • File access method and device of SD (Secure Digital) card
  • File access method and device of SD (Secure Digital) card
  • File access method and device of SD (Secure Digital) card

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0070] refer to figure 2 The flow chart of embodiment 1 of the file writing method of a kind of SD card shown, described file writes and relates to a DMA transfer process of writing file data in the continuous physical cluster of SD card from discontinuous memory address, this An embodiment may specifically include the following steps:

[0071] Step 201, configure the first file transfer information, the first file transfer information includes: the starting address and data length information of multiple pieces of file data in the memory, and the information of continuous physical clusters in the SD card;

[0072] Step 202, sequentially read data of corresponding lengths from multiple start addresses of the memory, and continuously write them into continuous physical clusters of the SD card.

[0073] In practice, the file has an end mark. In a preferred embodiment of the present invention, the step 202 may specifically include the following sub-steps:

[0074] Sub-step S11...

Embodiment 2

[0086] refer to image 3 The flow chart of Embodiment 1 of the file reading method of a SD card shown, the file reading involves a DMA transfer process of writing file data from a continuous physical cluster of the SD card to a discontinuous memory address, this implementation A specific example may include the following steps:

[0087] Step 301, configure the second file transfer information, the second file transfer information includes: information of continuous physical clusters in the SD card, and multi-segment address information in the memory;

[0088] Step 302, sequentially extracting data of corresponding lengths in continuous physical clusters of the SD card, and writing them into corresponding address segments in the internal memory.

[0089] In practice, the file has an end mark. In a preferred embodiment of the present invention, the step 302 may specifically include the following sub-steps:

[0090] Substep S21, according to the information of the first address s...

Embodiment 3

[0102] refer to Figure 4 A kind of flow chart of the file writing method embodiment 2 of SD card shown, described file writes and relates to a DMA transmission process of writing file data in discontinuous physical cluster group in SD card from continuous memory address, This embodiment may specifically include the following steps:

[0103] Step 401, configure the third file transfer information, the third file transfer information includes: continuous address segment information in the memory, and information of multiple physical cluster groups in the SD card;

[0104] Step 402, sequentially extracting data of corresponding lengths in continuous address segments of the internal memory, and writing them into corresponding physical cluster groups in the SD card respectively.

[0105] In practice, the file has an end mark. In a preferred embodiment of the present invention, the step 402 may specifically include the following sub-steps:

[0106] Substep S31, according to the n...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

The invention provides a file writing-in method of a SD (Secure Digital) card. The file writing-in process relates to a one-step DMA (Direct Memory Access) transmission process of wiring file data into a continuous physical cluster of the SD card from a discontinuous memory address. The method comprises the steps of: configuring first file transmission information, wherein the first file transmission information comprises initial addresses of multiple sections of file data in the memory and the information of the continuous physical cluster in the SD card; and sequentially reading data with corresponding length from the multiple sections of initial addresses of the memory, and continuously writing the data into the continuous physical cluster of the SD card. The invention can improve the direct memory access speed of the SD card and reduce the resource occupation of CPU (Central Processing Unit).

Description

technical field [0001] The invention relates to the field of data transmission control, in particular to a file reading method for an SD card, a file writing method for the SD card, a file reading device for the SD card, and a file writing device for the SD card. Background technique [0002] For a long time, SD cards (cards) with Flash Memory as storage bodies have been widely used in consumer electronic products due to their small size, low power consumption, rewritable and non-volatile characteristics. Especially in recent years, its range of applications has been increasing as prices have been falling and storage capacity has been increasing. [0003] Generally speaking, the SD card uses the FAT ((File Allocation Table, file allocation table) system to organize and manage the various files stored in it, and store the information related to the files in the FAT table for future access to files When used. The FAT table is a chain structure used for disk data (file) indexi...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
IPC IPC(8): G06F13/28G06F3/06
Inventor 艾国
Owner 中星智能系统技术有限公司
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Patsnap Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Patsnap Eureka Blog
Learn More
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic, Popular Technical Reports.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap|About US| Contact US: help@patsnap.com