©Copyright 2001-2010 SD Group (Panasonic, SanDisk, Toshiba) and SD Card Association
Physical Layer Simplified Specification Version 3.01
5
3. SD Memory Card System Concept
Description here is a blank for the Simplified Specification.
3.1 Read-Write Property
In terms of read-write property, two types of SD Memory Cards are defined:
• Read/Write (RW) cards (Flash, One Time Programmable - OTP, Multiple Time Programmable -
MTP). These cards are typically sold as blank (empty) media and are used for mass data storage,
end user video, audio or digital image recording
• Read Only Memory (ROM) cards. These cards are manufactured with fixed data content. They are
typically used as a distribution media for software, audio, video etc.
3.2 Supply Voltage
In terms of operating supply voltage, one type of SD Memory Cards is defined:
• High Voltage SD Memory Cards that can operate within the voltage range of 2.7-3.6 V.
3.3 Card Capacity
3.3.1 User Area and Protected Area
SD Memory Card has two accessible independent areas: User Area and Protected Area. User Area is
main memory area and Protected Area can be accessed by the authentication defined by the Part 3
Security Specification. Card Capacity means the sum of User Area Capacity and Protected Area
Capacity.
3.3.2 Card Capacity Classification
In terms of card capacity, three types of SD Memory Cards are defined:
• Standard Capacity SD Memory Card (SDSC) supports capacity up to and including 2 G bytes (2
31
bytes). All versions of the Physical Layer Specifications define the Standard Capacity SD Memory
Card.
• High Capacity SD Memory Card (SDHC) supports capacity more than 2 G bytes (2
31
bytes) up to 32
G bytes and is defined from the Physical Layer Specification Version 2.00.
• Extended Capacity SD Memory Card (SDXC) supports more than 32 G bytes (2
35
bytes) up to 2TB.
Only hosts that are compliant to the Physical Layer Specification Version 2.00 or later and the File
System Specification Ver2.00 or higher can access High Capacity SD Memory Cards and Extended
Capacity SD Memory Cards. Other hosts fail to initialize High Capacity SD Memory Cards and
Extended Capacity SD Memory Cards.
Only hosts that are compliant to the Physical Layer Specification Version 3.00 or higher and the File
System Specification Ver3.00 or later (exFAT supported) can access Extended Capacity SD Memory
Note:
1. The Part 1 Physical Layer Specification Version 3.00 and Part 2 File System Specification Version
3.00 allow Standard Capacity SD Memory Cards to have capacity up to and including 2 GB, High
Capacity SD Memory Cards to have capacity up to and including 32 GB and Extended Capacity
SD Memory Card to have capacity up to 2 TB.
2. Hosts that can access (read and/or write) SD Memory Cards with a capacity greater than 2 GB
and up to and including 32 GB, shall also be able to access SD Memory Cards with a capacity of
2 GB or less.
3. Hosts that can access (read and/or write) SD Memory Cards with a capacity greater than 32 GB
and up to 2 TB, shall also be able to access SD Memory Cards with a capacity of 32 GB or less.