SLSDM256BU STEC, SLSDM256BU Datasheet - Page 16

• Manufacturer Part Number: SLSDM256BU
• Manufacturer: STEC
• Type: MicroSD Cardr

Specifications of SLSDM256BU

• Density: 256MByte
• Operating Supply Voltage (typ): 3.3V
• Operating Temperature (min): 0C
• Operating Temperature (max): 70C
• Package Type: Not Required
• Pin Count: 8
• Operating Temperature Classification: Commercial
• Operating Supply Voltage (min): 2.7V
• Operating Supply Voltage (max): 3.6V
• Programmable: Yes
• Lead Free Status / RoHS Status: Compliant

SLSDMxxxB(I)U
4.2.2 SPI Bus Mode Protocol
The Serial Parallel Interface (SPI) Bus is a general purpose synchronous serial interface. The SPI mode
consists of a secondary communication protocol. The interface is selected during the first reset command
after power up (CMD0) and it cannot be changed once the card is powered on.
While the SD 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
The card identification and addressing methods are replaced by a hardware Chip Select (CS) signal.
There are no broadcast commands. For every command, a card (slave) is selected by asserting (active
low) the CS signal.
The CS signal must be continuously active for the duration of the SPI transaction (command, response
and data). The only exception occurs during card programming, when the host can de-assert the CS
signal without affecting the programming process.
The bidirectional CMD and DAT lines are replaced by unidirectional dataIn and dataOut signals.
The SPI bus signals are listed Table and the SPI bus topology is illustrated in Figure 8.
/CS
CLK
Data In
Data Out
Vdd, Vss
Signal
Host to card chip select
Host to card clock signal
Host to card data signal
Card to host data signal
Power and ground
Table14: SPI Bus Signals
61000-04581-104, July 2007
Description
Industrial Grade microSD Card Datasheet
16