Apalis Carrier Board Design Guide
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Apalis
Pin
Apalis
Signal Name
I/O
Type
Power
Rail
Description
186
SD1_D0
I/O
CMOS
3.3V
Data signals [3:0] - used for SD, MMC and SDIO interfaces; add
external pull-up resistors
188
SD1_D1
I/O
CMOS
3.3V
176
SD1_D2
I/O
CMOS
3.3V
178
SD1_D3
I/O
CMOS
3.3V
180
SD1_CMD
I/O
CMOS
3.3V
Command signal - add external pull-up resistor
184
SD1_CLK
O
CMOS
3.3V
Clock output
190
SD1_CD#
I
CMOS
3.3V
Card detect -add pull-up resistor if card detect is used
Table 23: 4bit SD/MMC/SDIO signals
2.13.2 Reference Schematics
Even if the selected module does not require pull-up resistors on the data and command lines, it is
recommended to place such resistors in the customer design and not just assemble them. This
ensures that the module is compatible with other Apalis modules. There is no dedicated write-
protection signal available on the standard Apalis pin-out. Any free GPIO capable signal can be
used if the write-protection function is required.
2.13.2.1
SD Card Slot Reference Schematics
Both interfaces, the SD1 and the MMC1, can be used as SD Card slot interface. However, it is
recommended to use the MMC1 if only one card interface is used. According to the SD card
specifications, the host should be able to control the supply rail of the card. This allows the host to
cycle the supply rail of the card in order to do a full reset of the controller in the SD card. Most
cards do not require this procedure and work perfectly without a power switching feature. For
switching the card power rail, any free GPIO can be used. However, if the MMC1_D4 (pin 148) is
used, the latest Toradex BSP works without need for modifications.
Figure 42: 4bit SD Card Slot Reference Schematic
2.13.2.2
MMC Card Slot (8bit) Reference Schematics
Please note the different pin numbering of the MMC card in the following schematic. Even though
the selected 8-bit MMC card slot is compatible with SD cards, the pin numbering is different form
the normal SD cards.
693071010811
DATA2
1
CD/DATA3
2
CMD
3
VCC
4
CLK
5
GND
6
DATA0
7
DATA1
8
CD1
CD2 / GND
S1
S2
X10
100nF
16V
C67
10uF
10V
C68
GND
R61
68K
R60
33K
3.3V_SD
Micro SD Holder
MMC1_D2
MMC1_D3
MMC1_D0
MMC1_D1
MMC1_CMD
MMC1_CLK
MMC1_CD#
MMC1_D2
MXM3_154_M
MXM3_160_M
MXM3_144_M
MXM3_162_M
MXM3_164_M
MXM3_150_M
MXM3_146_M
MMC1_D3
MMC1_D0
MMC1_D1
MMC1_CMD
MMC1_CLK
MMC1_CD#
3.3V_SD
GND
MMC[0..6]
22R
RA18B
22R
RA18C
22R
RA18D
22R
RA20A
22R
RA20B
22R
RA20C
22R
RA20D
R62
68K
R63
68K
R64
68K
GND
R51
100K
SI-1024-X
2
1
6
T15A
R52
100K
SI-1024-X
3
5
4
T15B
MMC_CD1
22R
RA18A
0R
R104
0R
R110
GND
MMC_CD2
0R
R109
MM70-314-310B1
MMC1_CLK
154
Apalis - MMC
11 of 25
MMC1_CD#
164
MMC1_CMD
150
MMC1_D0
160
MMC1_D1
162
MMC1_D2
144
MMC1_D3
146
MMC1_D4
148
MMC1_D5
152
MMC1_D6
156
MMC1_D7
158
X1K
MMC1_PWR_CTRL
1nF
50V
C15
100pF
50V
C14
GND
TPD2EUSB30DRTR
1
3
2
D+
D-
D4
GND
MIC94070YMT-TR
VOUT
1
GND
2
VIN
3
ENABLE
4
GND-TH
5
IC22
GND
3.3V_SW
3.3V_SD
3.3V_SD
MMC1_PWR_CTRL
100nF
16V
C161
GND
(MXM3_148_M)
R159
100K
SD CARD POWER SWITCH
NA
NA
NA
NA
NA
NA
NA