Datasheet
- 14 -
datasheet SD Card
Rev. 1.0
MMBTFxxGWBCA-xMExx
5.2 Bus Protocol
5.2.1 SD Bus
For more details, refer to Section 3.6.1 of the SDA Physical Layer Specification, Version 3.00
5.2.2 SPI Bus
For more details, refer to Chapter 7 of the SDA Physical Layer Specification, Version 3.00
5.3 SD/microSD Card Pin Assignment
Figure 5-1. SD Memory Card shape and interface (top view)
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.
Figure5-1 shows the general shape of the shape and interface contacts of the SD Memor
y Card. The detailed physical dimensions and mechanical
description are given in section 5.4.
The following Table defines the card contacts:
NOTE:
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 pull
ed 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 l
ine 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 tra
nsfer operations
(refer to "SDIO Card Specification" for further details).
5) DAT2 line may be used as Read Wait signal in SDIO mode (re
fer to "SDIO Card Specification" for further details).
5.3.1 SD Card Pin Assignment
[Table 5-1] : SD Memory Card Pad Assignment
Pin # Name
Type
1
Description Name Type Description
SD Mode SPI Mode
1
CD/DAT3
2
I/O/PP
3
Card Detect /
Data Line [Bit 3]
CS
I
3
Chip Select (neg true)
2 CMD PP Command/Response DI I Data In
3VSS1 S Supply voltage ground VSS S Supply voltage ground
4V
DD S Supply voltage VDD S Supply voltage
5 CLK I Clock SCLK I Clock
6V
SS2 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
SD Memory
Card
9
132 45678
wp