User`s guide

multimedia
page 29
Secure Digital (SD) is a non-volatile
memory card format developed for use
in portable devices. It comes in dierent
packages and memory capacities. It is
mostly used for storing large amounts
of data. EasyMx PRO
™
v7 features the
microSD card slot. The microSD form
factor is the smallest card format currently
available. It uses standard SPI user inter-
face with minimum additional electronics,
mainly used for stabilizing communication
lines which can be signicantly distorted
at high transfer rates. Special ferrite is
also provided to compensate the voltage
and current glitch that can occur when
inserting and de-inserting microSD card
into the socket.
Enabling microSD
In order to access microSD card, you
must enable SPI communication
lines using SW13.1 – SW13.3 DIP
switches, as well as Chip Select (CS)
and Card Detect (CD) lines using
SW13.7 and SW13.8 switches.
FP3
FERRITE
E12
10uF
VCC-3.3V VCC-MMC
C33
100nF
DATA BUS
1
2
+3.3V
4
5
6
7
G
CS
Din
+3.3V
SCK
GND
Dout
CD
GND
CN14
MICROSD
VCC-MMC
R54
10K
R53
10K
SD-CS#
SPI-MISO
SPI-MOSI
SPI-SCK
SD-CD#
R58 27
microSD
CARD SLOT
O
N
SW13
SPI-MOSI
SPI-MISO
SPI-SCK
SD-CS#
SD-CD#
PA7
PH7
PA2
PA4
PA5
1 2 3 4 5
6
7 8
microSD card slot
EasyMx PRO
v7
Figure 15-2:
enabling
microSD
card commu-
nication
lines
Figure 15-1:
microSD card slot
connection schematics