connect external pullup resistors to all data lines even if only DAT0 is to be used. Otherwise,
non-expected high current consumption may occur due to the floating inputs of DAT1 and
DAT2 (in case they are not used).
For more details regarding the SD Bus topology, refer to Section 3.5.1 of the SDA Physical
Layer Specification, Version 2.00.
For more details regarding the SPI Bus topology, refer to Section 3.5.2 of the SDA Physical
Layer Specification, Version 2.00.
3.5 Electrical Interface The power scheme of SanDisk SD products is handled locally in each card and in the bus
master. Refer to Section 6.4 of the SDA Physical Layer Specification, Version 2.00.
3.5.1 Power Up
Refer to Section 6.4.1 of the SDA Physical Layer Specification, Version 2.00, for information
about power sequencing.
3.5.2 Bus Operating Conditions
SPI Mode bus operating conditions are identical to SD Card Bus Mode operating conditions. For
details, see Section 6.6 of the SDA Physical Layer Specification, Version 2.00.
3.5.3 Bus Timing
SanDisk SD-ROM cards operate at a maximum clock frequency of 25MHz. See Section 6.7 of
the SDA Physical Layer Specification, Version 2.00, for bus timing specifications.
3.6 Physical / Mechanical The following table specifies the physical attributes of the SanDisk SD Card.
Parameter Value Notes
Weight 2.0g maximum
Length 32mm +/- 0.1mm
Width 24mm +/- 0.1mm
Thickness 2.1mm +/- 0.15mm
SanDisk SD-ROM Cards are available in an SD card compatible form factor without a physical
(sliding) write-protect switch. As shown in the following package diagram, the SD-ROM Card
package has the write-protect "notch” in the write-enabled position, even though the card itself
is read-only.
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