Spi Mode - SanDisk 2GB - 2GB Micro Secure Digital Card Product Manual

SanDisk microSD™, microSDHC™ and microSDXC™ cards
Table 1 contains descriptions for each transfer mode.
Mode
Single Block
Multiple Block

1.7 SPI Mode

The SPI Mode is a secondary communication protocol for cards in the SanDisk
microSD Card Product Family. This mode is a subset of the SD Protocol, designed to
communicate with an SPI channel, commonly found in Motorola and other vendors'
microcontrollers. Detailed information about SPI Mode can be found in Section 7 or
the SDA Physical Layer Specification, Version 3.01.
January 2012 Version 2.5 © 2008 - 2012 SanDisk Corporation. SanDisk Confidential, subject to all applicable non-disclosure agreements
Table 1: Mode Descriptions
In this mode the host reads or writes one data block in a pre-specified length.
The data block transmission is protected with 16-bit CRC that is generated by
the sending unit and checked by the receiving unit.
The block length for read operations is limited by the device sector size (512
bytes) but can be as small as a single byte. Misalignment is not allowed. Every
data block must be contained in a single physical sector.
The block length for write operations must be identical to the sector size and
the start address aligned to a sector boundary.
This mode is similar to the single block mode, except for the host can read/
write multiple data blocks (all have the same length) that are stored or retrieved
from contiguous memory addresses starting at the address specified in the
command. The operation is terminated with a stop transmission command.
Misalignment and block length restrictions apply to multiple blocks and are
identical to the single block read/write operations.
Description
OEM Product Manual
2.5
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