Users Manual

GSM/GPRS Module Series
M66 Hardware Design
M66_Hardware_Design Confidential / Released 56 / 82
Figure 32: Reference Circuit for Micro SD Card
Table 18: Pin Name of the SD Card and T-Flash (Micro SD) Card
In SD card interface designing, in order to ensure good communication performance with SD card, the
following design principles should be complied with:
 Keep all the SD card signals far away from VBAT power and RF trace.
 Route all SD card signals as short as possible. Ensure the length of every trace does not exceed
10cm.
 The SD_CLK, SD_DATA and SD_CMD trace should be routed together. Keep trace difference of
Pin No. Pin Name of SD Card Pin Name of T-Flash (Micro SD) Card
1 CD/DATA3 DATA2
2 CMD CD/DATA3
3 VSS1 CMD
4 VDD VDD
5 CLK CLK
6 VSS2 VSS
7 DATA0 DATA0
8 DATA1 DATA1
9 DATA2