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REF: BB_SRM_xM
BeagleBoard-xM System
Reference Manual
Revision C2
Page 84 of 163
7.15
microSD
The board provides a single microSD interface. Its primary use is for providing the boot
source for SW. Unlike the BeagleBoard, it cannot be used for the typical SDIO or MMC
functions.
Figure 42
is the microSD interface design on the BeagleBoard.
U4A
PROCESSOR
MMC1_CLK
N28
MMC1_CMD
M27
MMC1_DAT0
N27
MMC1_DAT1
N26
MMC1_DAT2
N25
MMC1_DAT3
P28
C144
10uF,CER,0805,6.3V
microSD
P7
SCHA2B0300
DAT2
1
CD/DAT3
2
CMD
3
VDD
4
CLOCK
5
VSS
6
DAT0
7
DAT1
8
GND
9
CD
10
GND3
11
GND4
12
TBD1
13
TBD2
14
TBD3
15
R
75
10K
VDD_MMC1
R
76
10K
R
77
10K
R
72
10K
R
73
10K
R
74
10K
C145
0.1uF,10V
R135
10K
VIO_1V8
U7A
TPS65950
CD1
P12
VMMC1.OUT
C2
R16
33
Figure 42.
microSD Interface
7.15.1
microSD Power
The microSD connector is supplied power from the
TPS65950
using the
VMMC1
rail.
The default setting on this rail is 3.0V as set by the Boot ROM and under SW control, can
be set to 1.80V for use with 1.8V cards. The maximum current this rail can provide is
220mA as determined by the
TPS65950
regulator. Maximum current can be limited by
the overall current available from the USB interface of the PC.
7.15.2
Processor Interface
There are no external buffers required for the microSD operation. The processor provides
all of the required interfaces for the microSD interface.
Table 11
provides a description
of the signals on the MMC card.
Table 11.
SD/MMC OMAP Signals
Signal Name
Description
I/O
Pin
MMC1_CLK
SD/MMC Clock output.
O
N28
MMC1_CMD
SD/MMC Command pin
I/O
M27
MMC1_DAT(0..7)
SD/MMC Data pins
I/O
N27,N26,N25,P28,P27,
Summary of Contents for XM C2
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