UM0851 datasheet(93/245 Pages) STMICROELECTRONICS

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UM0851

Communication device drivers

Doc ID 16604 Rev 2

93/245

4.7

SDIO driver

An SDIO card is a combination of an SD card and an I/O device. This kind of combination is

increasingly found in portable electronics devices. SDIO cards define a standard protocol at

several layers, including mechanical, electrical, power, signaling and software.

A large number of different SDIO devices can be now found in consumer applications, like

GPS receivers, Wi-Fi or Bluetooth adapters, modems and Ethernet adapters, Flash

memories and other mass storage media such as hard drives.

SPEAr300 and SPEAr320 embed a SDIO controller described in this section.

4.7.1

Hardware overview

SDIO stands for secure digital input output. SD/MMC is a memory card specifically

designed to meet the security, capacity, performance, and environment requirements

inherent in newly emerging audio and video consumer electronic devices. In addition to the

SD memory card, there is the SD I/O (SDIO) card. The SDIO card specification is defined in

a separate specification named "SDIO card specification" that can be obtained from the SD

Association. The SDIO specification defines an SD card that may contain interfaces

between various I/O units and an SD hosts. The SDIO card may contain memory storage

capability as well as I/O functionality.

The Arasan SDIO host controller included in the SPEAr300 and SPEAr320 customization

has an AMBA compatible interface and conforms to the SD host controller standard

specification version 2.0. It handles SDIO/SD protocol at transmission level, packing data,

adding cyclic redundancy check (CRC), setting of start/end bit and checking for transaction

format correctness. The host controller provides programmed I/O and DMA data transfer

method.

Figure 23.

SDIO block diagram

UM0851 Datasheet(PDF) 93 Page - STMicroelectronics