Sd Card Interface - Quectel EC21 Series Hardware Design

3.13. SD Card Interface

EC21 series module supports SDIO 3.0 interface for SD card. The following table shows the pin
definition of SD card interface.
Table 15: Pin Definition of SD Card Interface
Pin Name Pin No.
SDC2_DATA3 28
SDC2_DATA2 29
SDC2_DATA1 30
SDC2_DATA0 31
SDC2_CLK 32
SDC2_CMD 33
VDD_SDIO 34
SD_INS_DET 23
The following figure shows a reference design of SD card.
EC21_Series_Hardware_Design
I/O Description
DIO SD card SDIO data bit 3
DIO SD card SDIO data bit 2
DIO SD card SDIO data bit 1
DIO SD card SDIO data bit 0
DO SD card SDIO clock
DIO SD card SDIO command
PO SD card SDIO pull-up power
DI SD card insertion detect
Figure 25: Reference Circuit of SD Card Interface
LTE Standard Module Series
Comment
SDIO signal output voltage can
be selected according to the
signal output voltage supported
by SD card, see SD 3.0 protocol
for more details.
If unused, keep them open.
1.8/2.85 V power domain.
Configurable power supply.
Cannot be used for SD card
power supply.
If unused, keep it open.
1.8 V power domain.
If unused, keep it open.
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