---
title: Secure digital input/output interface (SDIO)
categories: SDIO, STM32F4
...

Introduction
============

What is SDIO?
-----------------
- A SDIO (Secure Digital Input Output) card is an extension of the SD specification to cover I/O functions. 
- Host devices that support SDIO can use the SD slot to support: 
   1.  GPS receivers.
   2.  digital cameras. 
   3.  RFID readers. 
   4.  FM radio tuners.
   5.  TV tuners. 
   6.  Wi-Fi.
   7.  Bluetooth. 

 Many other SDIO devices have been proposed, but it is now more common for I/O devices to connect using the USB interface.
- SDIO cards support most of the memory commands of SD cards. SDIO cards can be structured as 8 logical cards, although currently, the typical way that an SDIO card uses this capability is to structure itself as one I/O card and one memory card.

.. image:: /sdio1.png
.. image:: /sdio2.png

Difference of SD/MMC/SDIO
--------------------------



Speed class rating
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Reference
==========
- `Secure Digital wiki<http://en.wikipedia.org/wiki/Secure_Digital#SDIO>`_
- `SDIO接口介绍<http://en.wikipedia.org/wiki/Secure_Digital#SDIO>`_
-  `Linux（open source）的 SD/MMC/SDIO 支援現況概要<http://www.jollen.org/blog/2007/01/open_source_sd_mmc_sdio.html>`_
-  `SD/MMC/SDIO概念區分<http://bbs.ednchina.com/BLOG_ARTICLE_198217.HTM>`_
- `STM32 控制 SD 卡<http://www.360doc.com/content/12/0411/15/9707346_202767012.shtml>`_
- `STM32 + SDIO + FATFS 文件系统 直讀 SD 卡<http://ntn314.blog.163.com/blog/static/16174358420112263456948/>`_ 
- `零死角玩轉 stm32 - 高級篇之 SDIO（4bit + DMA、支持SDHC、帶協議分析）<http://www.eeboard.com/tutorials/%E9%9B%B6%E6%AD%BB%E8%A7%92%E7%8E%A9%E8%BD%ACstm32-%E9%AB%98%E7%BA%A7%E7%AF%87%E4%B9%8Bsdio%EF%BC%884bit-dma%E3%80%81%E6%94%AF%E6%8C%81sdhc%E3%80%81%E5%B8%A6%E5%8D%8F%E8%AE%AE%E5%88%86%E6%9E%90/>`_