SanDisk 4GB micro SDHC Memory Card for Product Manual - Page 11

SanDisk microSD™, microSDHC™ and microSDXC™ cards Table 1 contains descriptions for each transfer mode. OEM Product Manual 2.5 Table 1: Mode Descriptions Mode Single Block Multiple Block Description 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. 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 6