Specifications
©Copyright 2001-2013 SD Group (Panasonic, SanDisk, Toshiba) and SD Card Association
Physical Layer Simplified Specification Version 4.10
11
3.7 SD Memory Card–Pins and Registers
3.7.1 SD Bus Pin Assignment
The SD Memory Card has the form factor 24 mm x 32 mm x 2.1 mm or 24 mm x 32 mm x 1.4 mm.
SD Memory
Card
1
2
3
4
5
6
7
8
9
wp
Figure 3-11: SD Memory Card Shape and Interface (Top View)
Figure 3-11 shows the general shape of Standard Size and interface contacts of the SD Memory Card.
The detailed physical dimensions and mechanical description are given in Part 1 Mechanical Addenda.
Table 3-1 defines the card contacts:
Pin # SD Mode SPI Mode
Name Type
1
Description Name Type
1
Description
1
CD/DAT3
2
I/O/PP
3
Card Detect/
Data Line [Bit 3]
CS
I
3
Chip Select (neg true)
2
CMD
I/O/PP
Command/Response
DI
I
Data In
3
VSS1
S
Supply voltage ground
VSS
S
Supply voltage ground
4
VDD
S
Supply voltage
VDD
S
Supply voltage
5
CLK
I
Clock
SCLK
I
Clock
6
VSS2
S
Supply voltage ground
VSS2
S
Supply voltage ground
7
DAT0
I/O/PP
Data Line [Bit 0]
DO
O/PP
Data Out
8
DAT1
4
I/O/PP
Data Line [Bit 1]
RSV
9
DAT2
5
I/O/PP
Data Line [Bit 2]
RSV
1) S: power supply; I: input; O: output using push-pull drivers; PP: I/O using push-pull drivers;
2) The extended DAT lines (DAT1-DAT3) are input on power up. They start to operate as DAT lines after
SET_BUS_WIDTH command. The Host shall keep its own DAT1-DAT3 lines in input mode, as well, while they are not
used.
3) At power up this line has a 50KOhm pull up enabled in the card. This resistor serves two functions Card detection and
Mode Selection. For Mode Selection, the host can drive the line high or let it be pulled high to select SD mode. If the host
wants to select SPI mode it should drive the line low. For Card detection, the host detects that the line is pulled high. This
pull-up should be disconnected by the user, during regular data transfer, with SET_CLR_CARD_DETECT (ACMD42)
command
4) DAT1 line may be used as Interrupt Output (from the Card) in SDIO mode during all the times that it is not in use for
data transfer operations (refer to "SDIO Card Specification" for further details).
5) DAT2 line may be used as Read Wait signal in SDIO mode (refer to "SDIO Card Specification" for further details).
Table 3-1: SD Memory Card Pad Assignment