SD Card -Overview

SD Card -OverviewDescription of SD card features available to application developers -and what a device creator must write to provide SD card support. -

SD memory cards (Secure Digital memory cards) are flash-based memory cards -designed to provide secure high capacity data storage.

The SD controller supports the Simplified SD Physical layer specification -version 2.0 which is owned by the SD Card Association and the SD -Group.

The SD memory card standard is defined to be protocol forward compatible -with MultiMediaCard version 2.11 and it is possible for a MultiMediaCard to -be inserted into an SD memory card socket and host systems to support both -types of card.

Purpose

SD cards are based on MultiMediaCards (MMC) -but with additional functionality detailed below. Symbian platform support -for SD is built on top of the MMC support. This section describes the additional -functionality available to applications using SD cards. This section also -describes the additional work required to support SD cards.

Required background

You should be familiar with -the following:

MMC -Controller
SD Simplified Specification

Key concepts and terms

An SD card is very similar -to a MultiMediaCard (MMC) but with additional features to support high capacity, -high speed, secure storage.

As SD cards are very similar to MMC, you -should read the section on MMC -Controller Architecture before reading the SD -Controller documentation.

Architecture

SD support is divided into two parts, -the Platform Independent Layer (PIL) and the Platform Specific Layer (PSL).

The -PIL is implemented as an E32 peripheral bus controller - EPBUSSD.DLL which -is a kernel extension and extends the functionality of the matching MMC library EPBUSM.DLL. -The EPBUSSD.DLL library consists of a generic peripheral -bus layer, which is identical to the one used for MMC, and a generic SD card -layer. The SD card layer is a superset of the MMC layer and derives additional -classes for SD cards from the MMC classes. These derived classes support the -additional features found in an SD card.

The additional functionality -available in an SD card includes:

an optional 4-bit wide -data bus
individual SD card addressing
support for card capacities -up to 32Gb
revised erase ranges -allowing smaller ranges to be erased from an SD card
optional secure data -area - Symbian Platform does not provide support for using the secure data -area on an SD card.

You, as a device creator, will need to write the PSL. Implementing -the PSL is described in SD -Controller PSL Implementation.

Key Classes

The classes used for SD cards are SD -specific versions of the classes used for the MMC cards and the main SD-related -are listed here.

- - - -Class -Description - - - - -

DSDStack

The SD protocol stack, derived from DMMCStack. -Uses the star topography to identify each SD card rather than the bus topography -used by MMC. Also handles individual card initialization.

- - -

TSDCard

Derived from TMMCard but contains the erase sector -size and any special formatting requirements for the SD card. Includes information -from the SD Card Configuration Register (SCR).

- - - -

Typical uses

The typical uses for the SD card classes -are the same as for MMC.

-MMC Controller - -MultiMediaCard -Technology -MMC Controller -Architecture -Command Objects - + + + + + +SD Card +OverviewDescription of SD card features available to application developers +and what a device creator must write to provide SD card support. +

SD memory cards (Secure Digital memory cards) are flash-based memory cards +designed to provide secure high capacity data storage.

The SD controller supports the Simplified SD Physical layer specification +version 2.0 which is owned by the SD Card Association and the SD +Group.

The SD memory card standard is defined to be protocol forward compatible +with MultiMediaCard version 2.11 and it is possible for a MultiMediaCard to +be inserted into an SD memory card socket and host systems to support both +types of card.

Purpose

SD cards are based on MultiMediaCards (MMC) +but with additional functionality detailed below. Symbian platform support +for SD is built on top of the MMC support. This section describes the additional +functionality available to applications using SD cards. This section also +describes the additional work required to support SD cards.

Required background

You should be familiar with +the following:

MMC +Controller
SD Simplified Specification

Key concepts and terms

An SD card is very similar +to a MultiMediaCard (MMC) but with additional features to support high capacity, +high speed, secure storage.

As SD cards are very similar to MMC, you +should read the section on MMC +Controller Architecture before reading the SD +Controller documentation.

Architecture

SD support is divided into two parts, +the Platform Independent Layer (PIL) and the Platform Specific Layer (PSL).

The +PIL is implemented as an E32 peripheral bus controller - EPBUSSD.DLL which +is a kernel extension and extends the functionality of the matching MMC library EPBUSM.DLL. +The EPBUSSD.DLL library consists of a generic peripheral +bus layer, which is identical to the one used for MMC, and a generic SD card +layer. The SD card layer is a superset of the MMC layer and derives additional +classes for SD cards from the MMC classes. These derived classes support the +additional features found in an SD card.

The additional functionality +available in an SD card includes:

an optional 4-bit wide +data bus
individual SD card addressing
support for card capacities +up to 32Gb
revised erase ranges +allowing smaller ranges to be erased from an SD card
optional secure data +area - Symbian Platform does not provide support for using the secure data +area on an SD card.

You, as a device creator, will need to write the PSL. Implementing +the PSL is described in SD +Controller PSL Implementation.

Key Classes

The classes used for SD cards are SD +specific versions of the classes used for the MMC cards and the main SD-related +are listed here.

+ + + +Class +Description + + + + +

DSDStack

The SD protocol stack, derived from DMMCStack. +Uses the star topography to identify each SD card rather than the bus topography +used by MMC. Also handles individual card initialization.

+ + +

TSDCard

Derived from TMMCard but contains the erase sector +size and any special formatting requirements for the SD card. Includes information +from the SD Card Configuration Register (SCR).

+ + + +

Typical uses

The typical uses for the SD card classes +are the same as for MMC.

+MMC Controller + +MultiMediaCard +Technology +MMC Controller +Architecture +Command Objects +

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