SDMJ-128 SanDisk, SDMJ-128 Datasheet - Page 68

• Manufacturer Part Number: SDMJ-128
• Manufacturer: SanDisk
• Type: MultiMedia Cardr

Specifications of SDMJ-128

• Density: 128MByte
• Operating Supply Voltage (typ): 3.3V
• Operating Temperature (min): -25C
• Operating Temperature (max): 85C
• Package Type: MMC
• Mounting: Socket
• Pin Count: 7
• Operating Temperature Classification: Commercial
• Operating Supply Voltage (min): 2.7V
• Operating Supply Voltage (max): 3.6V
• Programmable: Yes
• Lead Free Status / Rohs Status: Compliant

Revision 1.3
© 2005 SanDisk Corporation
5.3
5.4
5.5
Card Registers in SPI Mode
SPI Bus Protocol
Mode Selection
The register usage in SPI mode is summarized in Table 5-2. Most of them are inaccessible.
Table 5-2
While the MultiMediaCard channel is based on command and data bit streams, which are
initiated by a start bit and terminated by a stop, bit, the SPI channel is byte oriented. Every
command or data block is built of 8-bit bytes and is byte aligned to the CS signal (i.e., the
length is a multiple of 8 clock cycles).
Similar to the MultiMediaCard Protocol, SPI messages consist of command, response and
data-block tokens. The host (master) controls all communication between the host and
cards. The host starts every bus transaction by asserting the CS signal low.
The response behavior in SPI mode differs from MultiMediaCard mode in the following
three aspects:
· Selected card always responds to the command.
· Additional (8, 16 and 40 bit) response structures are used.
· Card encounters a data retrieval problem, it will respond with an error response (which
replaces the expected data block) rather than by a time-out, as in the MultiMediaCard
mode.
Only single and multiple block read/write operations are supported in SPI mode (sequential
mode is not supported). In addition to the command response, every data block sent to the
card during a write operation will be responded to with a special data response token. A
data block may be as big as one card sector and as small as a single byte. Partial block
read/write operations are enabled by card options specified in the CSD register.
The MultiMediaCard and RS_MultiMediaCard “wake up” in the MultiMediaCard mode.
The card will enter SPI mode if the CS signal is asserted (negative) during the reception of
the reset command (CMD0). Selecting SPI mode is not restricted to Idle state (the state the
card enters after power up) only. Every time the card receives CMD0, including while in
Inactive state, CS signal is sampled.
If the card recognizes that MultiMediaCard mode is required (CS signal is high), it will not
respond to the command and remain in MultiMediaCard mode. If SPI mode is required
Name
OCR
RCA
DSR
CSD
CID
Available in SPI mode
MultiMediaCard/RS-MultiMediaCard Registers in SPI Mode
Yes
Yes
Yes
No
No
5-3
Width [Bytes]
MultiMediaCard/RS-MultiMediaCard Product Manual
16
16
32
Card identification data (serial number,
manufacturer ID, etc.).
Card-specific data, information about
the card operation conditions.
Operation condition register.
Description
Chapter 5 –SPI Mode
04/21/05