Interface Description; Pins And Registers - SanDisk 2GB - 2GB Micro Secure Digital Card Product Manual

SanDisk microSD™, microSDHC™ and microSDXC™ cards
3 I
NTERFACE

3.1 Pins and Registers

The SanDisk microSD™ Card Product Family has exposed contacts on one side. The
host uses a dedicated connector to connect to microSD cards.
In Table 4, pin assignments for the SanDisk microSD Card are described for SD Bus
Mode and SPI Bus Mode
Note: Pin assignments are provided by the SDA Physical Layer Specification,
Version 3.01 and associated addendums (microSD). For more details, refer to Section
3.7 of the SDA Physical Layer Specification, Version 3.01
Pin No.
Name Type
2,5
1 DAT2 I/O/PP
2
2 CD/DAT3 I/O/PP
3 CMD PP
4 V S
DD
5 CLK
6 V S
SS
7 DAT0 I/O/PP
2,4
8 DAT1 I/O/PP
Notes: 1.
Type Key: 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 the SET_BUS_WIDTH command. It is the responsibility
of the host designer to connect external pull-up resistors to all data lines even if
only DAT0 is to be used. If not, there may be unexpected high current consumption
due to the floating inputs of DAT1 & DAT2 (if 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. The user should disconnect this pull-up with
SET_CLR_CARD_DETECT (ACMD42) command during regular data transfer.
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.
5.
DAT2 line may be used as Read Wait signal in SDIO mode.
January 2012 Version 2.5 © 2008 - 2012 SanDisk Corporation. SanDisk Confidential, subject to all applicable non-disclosure agreements 10
D
ESCRIPTION
Table 4: SD Bus Mode Pin Assignment
SD Mode
1
Description
Data Line [bit 2]
3
Card Detect/Data Line [bit 3]
Command/Response
Supply Voltage
I Clock
Supply voltage ground
Data Line [bit 1]
Data Line [bit 2]
OEM Product Manual
SPI mode
1
Name Type
RSV - Reserved
3
CS I Chip select (active low)
DataIn I Data In
V S Supply Voltage
DD
SCLK I Clock
V S Supply voltage ground
SS
DataOUT O/PP Data Out
4
RSV - Reserved
2.5
Description