• 07/14/2017
  • Public Content
Contents

SD Card Interface

The SD card interface supports SD memory at a maximum of 208MHz (SDR104 mode). An external level shifter is required. The level shifter needs to support dual voltage operation in case UHS-I or faster speeds are required. Signals going to an SD card connector should have ESD protection and EMI filtering.
 
 
Signal
Module Connector.Pin
Pin Direction
Use
SDCARD_LVL_CLK_FB
J2.77
Output
SD card clock feedback for aligning the SDIO data from the level shifter on the expansion board through the controller, there is a loopback through the SD card level shifter that drives this pin.
SDCARD_CD_N
J2.79
Output
SD card detect, active low when a card is present, pulled high with internal pull-up when a card is not present
SDCARD_PWR_DOWN_N
J2.91
Input
SD card power down indicates to SDIO device to power down.
SDCARD_LVL_SEL
J2.88
Input
SD card level select performs the 1.8 V to 3.0 V negotiation.
SDCARD_LVL_CMD_DIR
J2.90
Input
SD card command direction indicates whether a host is transmitting or receiving over the command pin.
SDCARD_LVL_DAT_DIR
J2.67
Input
SD card data direction indicates whether a host is transmitting or receiving over the data.
SDCARD_CLK
J2.75
Input
SD card clock
SDCARD_D0
J2.81
Bidirectional
SD card data 0, by default, during power up or reset, only data 0 is used for data transfer.
SDCARD_D1
J2.83
Bidirectional
SD card data 1
SDCARD_D2
J2.85
Bidirectional
SD card data 2
SDCARD_D3
J2.87
Bidirectional
SD card data 3
SDCARD_CMD
J2.89
Bidirectional
SD card command is used for card initialization and transfer of commands.

Product and Performance Information

1

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Notice revision #20110804