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

Industrial SLC SD for Automotive Applications

  When it comes to flash storage solutions for industrial OEM automotive applications, such as...

mSATA SSD
FAQs on Industrial mSATA SSDs

  The mSATA, otherwise known as the mini-SATA, is a slim drive format designed for...

Take a Closer Look at Embedded Memory Systems

  Embedded memory systems do excellent behind-the-scenes work, but at a conscious level, it’s not...

Life Cycle Management- SMART Commnands
Our Technical Success Stories: A Look at SMART Triggers

  No matter how high-quality or well-optimized your embedded storage is, it will eventually reach...

S316APG49-U3000-3 - SD - microSD - 16GB - MLC
Your MLC MicroSD FAQs, Answered

  Whether you’re searching for a reliable and high-quality flash storage solution for a commercial...

Delkin Support Evaluating pSLC
Understanding PseudoSLC (pSLC)

  Pseudo NAND (pSLC) technology is the latest cutting-edge solution in NAND flash storage. It...

What Is Write Amplification in True Embedded Applications?

  Embedded computing systems are designed to perform specific tasks, like writing data to the...

Our Comprehensive Application Engineering Support

   Delkin Devices is a state-of-the-art flash memory and storage SSD provider for OEMs for...

Taking a Look at Real Time Embedded & Operating Systems (RTOS)

  Real-Time Embedded & Operating Systems (RTOS) are operating systems (OS) for applications that process...

Delkin Devices Technical Success Stories- Female Engineer- Businesswoman
A Case Study in Flash Endurance and SMART Commands

  At Delkin, we don’t just pride ourselves on our state-of-the-art flash memory and storage...