SD Card Subsystem

The expansion board contains a micro SD card slot at J5 attached to the bottom side. See Expansion Board Interfaces for the location of the SD card slot.

The SD card interface is sourced from the Intel Joule module and routed to an NXP IP4856CX25 level shifter. The level shifter allows for the support of both 1.8 volt and 2.9 volt cards. The output of the level shifter is routed directly to the micro SD card connector.

The micro SD card connector power is sourced from the +3.3 volt buck/boost regulator.

Refer to the micro SD card specifications for electrical and power requirements. Refer to the NXP IP4856CX25 datasheet for the SD card interface signal specifications. The power from the level shifter can support a maximum current of 100 mA and has a supply voltage of 2.9 V.

Micro SD Card Connector Pinout

Pin #

Net Name

Direction

Signal Description

1

SDCARD_D2_CONN

Bidirectional

Data lane 2

2

SDCARD_D3_CONN

Bidirectional

Data lane 3

3

SDCARD_CMD_CONN

Bidirectional

 

4

+V3P3V_MICROSD

Output

+2.9 volt supply to SD card

5

SDCARD_CLK_CONN

Output

 

6

GND

Ground

Ground

7

SDCARD_D0_CONN

Bidirectional

Data lane 0

8

SDCARD_D1_CONN

Bidirectional

Data lane 1

 

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