Users Manual

GSM/GPRS Module Series
M66 Hardware Design
M66_Hardware_Design Confidential / Released 55 / 82
3.11. SD Card Interface
The module provides an SD card interface that supports many types of memory, such as Memory Stick,
SD/MCC card and T-Flash or Micro SD card. The following are the main features of SD card interface.
 Only support 1bit serial mode
 Not support the SPI mode for SD memory card
 Not support multiple SD memory cards
 Not support hot plug
 The data rate up to 48MHz in serial mode
 Up to 32GB maximum memory card capacity
With the SD card interface features and reference circuit shown as below, you can easily design the SD
card application circuit to enhance the memory capacity of the module. The users can store some
high-capacity files to external memory card. Such as in the automotive application system, the module
can record and store the audio file to the SD card, and also can play the audio files in SD card.
Table 17: Pin Definition of SD Card Interface
1)
If several interfaces share the same I/O pin, to avoid conflict between these alternate functions, only one
peripheral should be enabled at a time.
A reference design for Micro SD card is shown below.
Pin Name Pin No. Description
Alternate
Function
1)
SD_CMD 32 Command signal of SD card output PCM_IN
SD_CLK 33 Clock signal of SD card output PCM_OUT
SD_DATA 31 Data output and input signal of SD card PCM_SYNC
NOTE