Hardware resources ms_wp, sd_wp, and SD card write protection: gpi_09. The write protection switch for the driver to read the SD card is used for different operations. ms_cd, sd_cd, and plug-in card Detection: gpi_04. (Ms_cd and ms_wp on the left of the schematic diagram are
1. Manually mount/unmount the USB drive, SD cardFor ARM Linux, the first time you use a USB flash drive or SD, this file directory is not directly accessible, we need to mount it, and then the next use can be directly used. Through the online search data, now the U disk in the Liunx under the method of recording down;Step1: Insert SD
.... Change intoDev_mount Sdcard/mnt/sdcard2Auto/devices/platform/goldfish_mmc.0/devices/platform/mtk-sd.0/mmc_hostDev_mount Sdcard/mnt/sdcardAuto/devices/platform/goldfish_mmc.1/devices/platform/mtk-sd.1/mmc_host save and then exit. At this time, you will be in this folder to prepare a Vold.fstab.bak file.the next important step:Settings--Accessibility--Install the app to an external
1. Determine if the SD card exists returns TRUE indicates that there is1 /*determine if the SD card exists returns TRUE indicates that there is*/2 Public BooleanAvaiablemedia () {3String status =environment.getexternalstoragestate ();4 5 if(Status.equals (environment.media_mounted)) {6 retu
## Copyright (c) 2010 Samsung Electronics Co., Ltd.# Http://www.samsung.com/## This program is free software; you can redistribute it and/or modify# It under the terms of the GNU General Public License version 2# Published by the Free Software Foundation.#####################################Reader_type1 = "/dev/SDB"Reader_type2 = "/dev/mmcblk0"// The-Z string is "null". The length is 0.If [-Z $1] // determines whether the input parameter is null. If it is null, the function of the sd_fusing.sh s
Debugging related to SD card is often encountered in andorid development, such as MP3 files and image files.
When developing a simulator, you can simulate an SD card through a hard disk. The specific method is:
1. Create an SD car
The previous section describes how to store files to internal devices. Sometimes, you need to store files to external storage devices, such as SD cards. Because the SD card has a larger storage space and can easily share these files with other users.
Use the example in the previous section to save the text you entered on the
1. mksdcard command
Run cmd to enter the SDK tools directory and run the mksdcard command. The following help information is displayed:
We can see that sdcard image supports the FAT32 format. Usage: mksdcard [-l label]
-L the disk is followed by the volume label. For example, G indicates g disk;Size indicates the size, measured in KB and MB;File indicates the generated SD image file name, such as android_sdcard_image.
2. Simulate
Sometimes in order to need, the database will be saved to the external storage or SD card (for this situation can be encrypted data to prevent data from being cracked), such as an application to support multiple data, each data need to have a corresponding database, and the information in the database is particularly large, This is obviously more important to keep the database in an external storage or
1. SD card command format:
The SD card instruction consists of 6 bytes, as shown below:
Byte1: 0 1 x (command number, defined by the command mark. For example, if limit 39 is 100111, that is, hexadecimal 0x27, the first byte of complete limit 39 is 01100111, 0x27 + 0x40)Byte2-5: Command Arguments, Command parameters, s
BBB power on by pressing the button can decide to boot from the SD card, if there is a system from the SD card boot, if not on the boot from the eMMC. Because the BBB has already had the 4G eMMC, inside the factory existence Angstrom Linux, this system is specially for the embedded Linux system, therefore for the gener
Initialize the SD card.
I currently use the SPI mode, so I will only discuss the SPI mode here. In spi mode, all commands require that the CS foot be set to 0 first. So I will not emphasize this in the future.
Swap 0 to switch the SD card from SD mode to SPI mode. Judg
Android 2.2 software can be installed on SD for support, ADB commands have also been improved, for Android 2.2 firmware PM command support installation option parameters, the setinstalllocation parameter is added here. Here we can use ADB to execute the Linux PM command to add some parameters, such as ADB shell PM setinstalllocation 0. The last parameter 0 indicates auto. The Android system automatically selects this parameter, while 1 indicates the R
SD card mounting file system: VFS: Cannotopenrootdevice quot; mmcblk0p2 quot; solve the problem of using the initramfs file system. linux can run normally and read and write SD cards normally. However, if it is mounted to the SD card, the disk cannot be mounted. the bootar
android.util.log;/** * is used to support access to the database stored on the SD card **/public class Databasecontext extends Contextwrapper { /** * Constructor * @param base context */public databasecontext (context base) {Su Per (base); /** * Get the database path, if not present, create object Object * @param name * @param mode * @param FA Ctory */@Override public File
/**************************************************************************** * I.MX6 uSDHC SD card reg Ister * Statement: * This article is mainly to record the SD card registration related processes and some problems encountered. * 2015-12-20 Shenzhen Nanshan Ping Shan village Zengjianfeng ***************************
The reading and writing of SD cards is the most common operation in the development of Android applications. The following describes the SD card read and write operation mode:
1. Get the root directory of SD card
Copy Code code as follows:
String sdcardroot
Recently, we are studying the driver of pxa300 SD card.Program, Figured out the SD card initialization process, the record is as follows
1. The pxamci_probe () function calls mmc_alloc_host () to allocate the mmc_host structure and initializes the mmc_rescan latency task.
2. initialize the mmc_host structure, initialize the MMC hardware controller registers,
README for Friendlyarm Tiny4412-----------------------------------------------------1. Build UbootA) Install the toolchain (arm-linux-gcc-4.5.1-v6-vfp-20120301.tgz) and set it up.environment variable path, guaranteed to work properly.b) Unzip the uboot_tiny4412-20130729.tgz and enter the appropriate directoryTar xzf uboot_tiny4412-20130729.tgzc) Configure Uboot and compileCD uboot_tiny4412Make Tiny4412_configMaked) compiling tools for generating BL2Make-c Sd_fuseOrCD sd_fuse; Make---------------
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