SimCom SIM5218E Hardware Design page 48

SIM5218E Hardware Design
■ Supports 4-bit SD, 1-bit SD, and 1-bit MMC interface
■ SW-configurable edge latching (falling or rising)
■ SW-configurable data and command values change (rising or falling edge)
■ Clock-gating for power saving (and a power-saving option to always turn the clock off
when bus is idle)
■ Flow control option to prevent overflow and underflow
■ SD_CLK output up to 25 MHz
Following figure illustrate and describe the MMC/SD interface.
As mentioned, the MMC/SD interface supports SD according to the SD physical layer
specification 2.0, up to 4-bit data mode. It is also capable of supporting 1-bit MMC according to
MCC specification 3.31. While the same hardware controller is used, the initialization for SD
cards and MMCs are different. SIM5218E will auto-detect which card is inserted (SD or MMC, or
no card) and will proceed accordingly.
Table 27: MMC/SD pin of SIM5218E
Direction
Name
Input /Output
SD_DATA0
Input /Output
SD_DATA1
Input /Output
SD_DATA2
Input /Output
SD_DATA3
Output
SD_CLK
Output
SD_CMD
Output
VREG_AUX1
SIM5218E_HD_V1.03
Figure 27： MMC/SD interface
Pin
(On board-to-board connector)
36
37
38
39
34
35
40
47
voltage scope( V )
Min Type Max
2.7 2.85 3.0
2.7 2.85 3.0
2.7 2.85 3.0
2.7 2.85 3.0
2.7 2.85 3.0
2.7 2.85 3.0
2.7 2.85 3.0
11.06.2009