Delkin Blog

SD Card Pinout Basics

 

The serial interface of SD cards has made them hugely popular in both consumer and industrial devices for OEMs. The SD Card Association tightly controls the specifications of SD cards, including the SD card pinout, so there are universal standards for everything from physical interfaces to command protocols that make integration seamless and easy. SD cards are designed to meet the needs of both consumer and industrial markets and their differing budgets. Most consumer devices rely on MLC flash memory, while industrial devices use SLC flash.  An SD card pinout can vary depending on the mode of the card.

 

SD Card Modes

SD cards automatically use SD mode for the bus protocol. SD mode offers high speeds and bus widths of between one and four bits in clock serial mode. Users can override the SD mode default, however, to use the card in SPI mode. SPI mode is best suited for applications in which a slower, simpler card is ideal. The speed difference with SD and SPI modes can be significant, as the card can only operate at one bit in SPI mode.

 

SD Card Pinouts in SD Mode

Each SD card, regardless of mode, has 9 pins, with the eighth pin at one end and the ninth at the other. When running in SD mode, the pinout and signal functions look like this:

 

  1. DAT1 – Data bit one
  2. DATA0/DO – Data bit 0
  3. Vss2 – Ground 2
  4. CLK – Clock
  5. Vcc – Supply voltage
  6. Vss1 – Ground 1
  7. CMD/DI – Command line
  8. DAT3/CS – Data bit 3
  9. DAT2 – Data bit 2

 

With this pinout, SD cards can support normal and high speed modes.

 

SD Card Pinouts in SPI Mode

SPI mode offers simpler functioning, and not every pin has a connection. The pinout and the signal functions are as follows:

 

  1. RSV – Reserved
  2. DO – Master In/Slave Out (or MISO)
  3. Vss – Ground
  4. CLK – Clock
  5. Vcc – Supply voltage
  6. DI – Master Out/Slave In (MOSI)
  7. CS – Chip Select
  8. NC – No connection
  9. RSV – Reserved

 

Do you have questions about SD card pinouts and using SD cards for flash storage? Delkin is here to provide the information you need and help you evaluate all of your options for industrial-grade, rugged memory. Talk to our product team today.

 

Contact

  • This field is for validation purposes and should be left unchanged.

 

 

Related Posts

Customer Success Story: Maximizing Speed and Performance with a Locked BOM

  For industrial customers, the prospect of frequently recertifying components like embedded memory is simply...

Understanding the Architecture of an SLC USB Flash Drive

  Flash drives are one of the most recognizable, widely used forms of memory. One...

FAQs About the Industrial CFast Card

  Industrial CFast cards offer high-capacity storage solutions for applications that are migrating to a...

Industrial SATA for Controls/Automation

  In recent years, an increased use of controls/automation has revolutionized efficiency in factory settings....

Customer Success Story: Application Lifecycle Challenges

  In 2009, mSATA was introduced to the market to address the demand for consumer...

Answering Common Questions About M.2

  Flash memory form factors that are widely compatible and appropriate for a variety of...

Temperature and SLC NAND Flash Memory: What You Need to Know

  NAND flash memory is the preferred form of storage for everything from consumer smartphones...

Concept of Communication Network Applications in City
Industrial CF Cards for the Communications/Networking Industry

  Which kind of embedded storage is best for industrial applications?  It is an understandable...

Delkin PRD SD MICROSD
The ABC’s of microSD and SD Cards

  It used to be so simple.  Just select a Class 10 card and you...

Delkin Devices M.2 2280, PCIe, 128 GB SSD featured for the new UltraZed-EV

Delkin Devices SSD, Internal, M.2 2280 is featured for NVMe SSD capability to the...