SMS512DFA5E NUMONYX, SMS512DFA5E Datasheet - Page 45

• Manufacturer Part Number: SMS512DFA5E
• Description: MICROSD CARD SMS 512MB FLASH MEM
• Manufacturer: NUMONYX

Specifications of SMS512DFA5E

• Memory Size: 512MB
• Memory Type: SD (Secure Digital)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

SMSxxxDF
7.2
7.2.1
Figure 32. SD memory card system SPI mode bus topology
SPI bus protocol
Whereas the SD channel is based on command and data bit streams initiated by a start bit
and terminated by a stop bit, the SPI channel is byte-oriented. Every command or data block
is built up with 8-bit bytes and is byte-aligned to the CS signal (that is, the length is a multiple
of 8 clock cycles).
Like in the SD protocol, messages in the SPI protocol consist of command, response and
data-block tokens. All communications between host and cards are controlled by the host
(master). The host starts every bus transaction by asserting the CS signal Low.
The response behaviors in SPI mode and SD mode differ in three ways. In the SPI mode:
In addition to returning a response for every command received, the card returns a special
data response token for every data block received during write operations.
Mode selection
The SD memory card wakes up in the SD mode. It will enter the SPI mode if the CS signal is
asserted (Low) when the Reset command (CMD0) is received.
The only way to return to the SD mode is to start a new power-down/power-up sequence.
In SPI mode, the SD card protocol state machine does not apply.
the selected card always responds to the command
two additional (8- & 16-bit) response structures are used
when the card encounters a data retrieval problem, it sends an error response in place
of the expected data block (in the SD mode the card does not respond but implements
a timeout).
HOST
CLK
DataIN
DataOut
CS (A)
CS (B)
CS (B)
V
V
DD
SS
CLK, DataIN, DataOut
CLK, DataIN, DataOut
CLK, DataIN, DataOut
Serial peripheral interface (SPI) mode
V
V
V
CS
V
V
V
CS
CS
DD
DD
DD
SS
SS
SS
MultiMediaCard
SD memory
SD memory
(SPI mode)
(SPI mode)
(SPI mode)
card (A)
card (B)
(C)
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