What is the SD Card? - JCXD Flash-

What is the SD Card? TF Card is divided into what categories?

2018-07-21

SD memory card is a new-generation memory device based on semiconductor flash memory. It is widely used in portable devices due to its small size, fast data transmission speed, hot swappable, etc., such as digital cameras. Personal digital assistant (foreign language abbreviation PDA) and multimedia player.

SD card capacity currently has 3 levels, that is SD, SDHC and SDXC.

The following table shows the grade capacity range and standard disk format.

Capacity Levels	Capacity Range	Standard Disk Format
SD	Below 2GB	FAT12, 16
SDHC	2GB to 32GB	FAT32
SDXC	32GB to 1TB	EXFAT

Capacity of SD: 8MB, 16MB, 32MB, 64MB, 128MB, 256MB, 512MB, 1GB, 2GB

Capacity of SDHC: 2GB, 4GB, 8GB, 16GB, 32GB

Capacity of SDXC: 32GB, 48GB, 64GB, 128GB, 256GB, 512GB, 1TB, 2TB

SD has different levels depending on the data transfer speed. Speed grade

There are two ways to represent it:

"X" notation (SD1.0 specification, not used now):

It is calculated by the rate calculation method of CD-ROM's 150kB/s as 1x speed. Basically, they are up to six times faster (900 kB/s) than standard CD-ROMs, while high-speed SD cards can transmit 66x (10 MB/pc) and 133x or higher. Some digital cameras require a high-speed SD card to take pictures more smoothly, and to take photos continuously. Until December 2005, most devices followed the SD card's 1.01 specification, while the higher-speed to 133x devices also followed the 1.1 specification, up to 12.5MB/pc.

Speed Grade	Read Speed	Equal to Speed Class
13X	2.00	2
26X	4.00	4
40X	6.00	6
66X	10.00	10

The speed grading method for the SD card in the SD2.0 specification is that the rates of the normal card and the high speed card are defined as four levels of Class 2, Class 4, Class 6, and Class 10. Prior to the advent of the Class10 card, there was a band of Class11 and Class13 cards, but this standard was ultimately not agreed by SDA.

The SD3.01 specification is called a superfast card and the rates are defined as UHS-I and UHS-II. As of the second quarter of 2013, only UHS-I cards have been listed. UHS-II was released in the fourth quarter of 2012, but in terms of the speed of technology development before 2014, UHS-I is enough to spend more than 2014 or even longer. The speed grades of UHS-I cards are divided into UHS-Class0 and UHS-Class1. The Class of UHS-I is different from the Class of SD2.0. There is no explicit Class0 card, and the literal meaning is that it does not reach the Class1 card. Maybe the old standard of the future will be classified as Class0. Class1 represents a maximum read of 104MB/s, while the Class in the SD2.0 standard represents the minimum speed range for writing.

The different reading speeds and application requirements that can be met are shown in the table below:

Speed Grade	Speed (MB/s)	Applied Ranges
Class 0		Less than Class 2 and unlabeled speed class
Class 2	Min Write 2.0	Watch general definition TV, digital camera shooting
Class 4	Min Write 4.0	Smooth playback of high-definition television (HDTV), digital camera continuous shooting
Class 6	Min Write 6.0	SLR camera continuous shooting, and the use of professional equipment
Class 10	Min Wirte 10	Recording and playback of full HD TV
UHS-I	Write 50/ Read 104	Professional full HD TV real-time recording
UHS-I	Write 156/ Read 312	Future world

Computer card reader exception handling method:

1 If the SD card can view the photos normally in the camera and cannot be recognized by plugging in the computer, it is likely that the driver of the SD port does not match. Find the correct SD card driver update.

2 After the update, if there is a yellow warning number in the device manager, and the software with the u disk protection function installed in the computer may be incompatible, the computer can be recognized by restarting the computer.

Maintenance knowledge

1. If the SD card is used after viewing the camera on the computer, if you need to flip the photo you are looking at, please copy the photo to the computer and then operate it. If you modify it directly in the card, When the card is placed in the camera to view related pictures, there will be cases where the photo cannot be viewed. After a large number of pictures have been modified, the SD card may be “snapped” and formatted before it can be used normally.

2. SD card in the camera, it may be that the SD card is faulty or the life is up. If there is a card machine or a crash in the process of shooting the Please use the card reader to export the contents of the card to save and then format. However, it is recommended not to store important data usage, because other places may be weather-beaten and will soon fail.

3. SD card has a small secret, if you accidentally use the SD card to break or break can not be used, do not rush to throw away the "discarded" card, carefully open the surface of the SD card, You will see that there is still a small TF card hidden in the phone, which can be used by most mobile phones. It can also be used with an SD card TF adapter. (This card is an unconventional SD card. The SD card usually consists of a PCBA+ master solution + FLASH instead of a TF card transfer).

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