Manual

803M Series Industrial Grade microSD Card Product Manual v2.0Cactus Technologies
®
8
Signal Name Dir. Description
CD/DAT3 (SD mode)
CSN (SPI mode)
I/O/PP
I
This pin is an input with 50Kohm pullup at power
up time and can be used for card detection or SPI
mode selection. For regular data transfer, the
host should disconnect the pullup by issuing a
SET_CLR_CARD_DETECT command to the card.
In SPI mode, this is an input for chip select.
CMD
SDI
PP
I
This pin is used by the host to send command to
the card and is used by the card to send response
back to the host.
In SPI mode, this is serial data input to the card.
CLK/SDCLK
I
This is clock input to the card.
DAT0
SDO
I/O/PP
O
This pin is input on power up. It will function as
a data line once the host has issued a SET_BUS_
WIDTH command.
In SPI mode, this pin is serial data out from the
card.
DAT1
DAT2
i/O/PP
These pins are inputs on power up. They will
function as data lines once the host hast issued a
SET_BUS_WIDTH command.
Table 3-6. Signal Description
Bus Protocol
3.3.
The Cactus Technologies microSD products bus protocol is compliant to SDA Physical Layer
Specications, Version 1.01, 1.1 and 2.0. Please refer to those documents for details about bus
protocol and timing.
Signal Description
3.2.
Table 3-6 describes the I/O signals. Signals whose source is the host are designated as inputs while
signals that the SD Card sources are outputs. The SD Card logic levels conform to those specied in
the SDA Physical Layer Specication, version 1.1.