User's Manual

Smart Machine Smart Decision
SIM7100A_User Manual_V1.01 2014-12-11
44
3.7 MMC/SD and SDIO Interface
SIM7100A provides one 4-bit SD/MMC interface and one SDIO interface with clock rate up to 52 MHz.
3.7.1 MMC/SD Interface Pin Description
The operation voltage of MMC/SD interface is 2.85V. It supports 1-bit SD/MMC or 4-bit SD data
transmission mode. Though the same hardware controller is used, the initialization procession for SD or
MMC cards is different.
Note: Interface with SD/MMC memory cards up to 32GB
Table 22: MMC/SD Pin description
Table 23: MMC/SD Electronic characteristic*
Symbol Parameter
Min Typ Max Unit
VDD_EXT** LDO power output
2.71 2.85 2.99 V
V
IH
High-level input voltage
0.65·VDD_EXT - VDD_EXT+0.3 V
V
IL
Low-level input voltage
-0.3 0 0.3·VDD_EXT V
V
OH
High-level output voltage
2.71 2.85 2.99
V
V
OL
Low-level output voltage
0 0 0.45 V
Note:
*For SD_DATA0-SD_DATA3 ， SD_CLK and SD_CMD ， GPIO44 is 1.8V operation voltage.
**VDD_EXT must be set with 2.85V output.
Pin name Pin No. Function
SD_DATA0
22
SD/MMC card data0
SD_DATA1
23
SD card data1
SD_DATA2
24
SD card data2
SD_DATA3
25
SD card data3
SD_CLK
26 SD card clock
SD_CMD
21 SD card command
GPIO44
48 SD card detecting