GSM/GPRS Module
M85 Hardware Design
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3.10. SD Card Interface
The module provides SD card interface that support 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 supports 1bit serial mode.
Does not support the SPI mode SD/MMC memory card.
Does not support hot plug.
Up to 26MHz data rate in serial mode.
Up to 32GB maximum memory card capacity.
With interface features and reference circuit of SD card shown in Figure 37, the users can easily design
the SD card application circuit to enhance the memory capacity of the module. The module can record
and store the audio files to the SD card, and play the audio files from SD card as well.
Table 16: Pin Definition of the SD Card Interface
The reference design for Mirco SD card is shown as below.
SIM_DATA
C7
SIM card data I/O
SIM_DETECT
C8
Pulled down GND with external circuit. When the tray is present, C4 is
connected to C8.
Pin NO.
Name
Description
34
SD_CMD
Command signal of SD card interface
35
SD_CLK
Clock signal of SD card interface
36
SD_DATA0
Data output and input signal of SD card interface
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