Product manual

Introduction to the Industrial Grade SD Card

1.5.9. Industrial Grade SD Card—SD Bus Mode

The following sections provide valuable information on the Industrial Grade SD Card in SD Bus mode.

1.5.9.1. Industrial Grade SD Card Standard Compliance

The Industrial Grade is fully compliant with SD Card Physical Layer Standard Specification V1.01. The structure of

the Card Specific Data (CSD) register is compliant with CSD Structure 1.0.

1.5.9.2. Negotiating Operation Conditions

The Industrial Grade SD Card supports the operation condition verification sequence defined in the SD Card

standard specifications. Should the SD Card host define an operating voltage range, which is not supported by the

Industrial Grade SD Card it will put itself in an inactive state and ignore any bus communication. The only way to

get the card out of the inactive state is by powering it down and up again.

In Addition the host can explicitly send the card to the inactive state by using the GO_INACTIVE_STATE

command.

1.5.9.3. Card Acquisition and Identification

The Industrial Grade SD Card bus is a single master (SD Card host application) and multi-slaves (cards) bus. The

Clock and Power lines are common to all cards on the bus. During the identification process, the host accesses each

card separately through its own command lines. The Industrial Grade SD Card’s CID register is pre-programmed

with a unique card identification number, which is used during the identification procedure.

In addition, the SD Card host can read the card’s CID register using the READ_CID SD Card command. The CID

floor. The SD Card host can only read this register and not write to it.

An internal pull-up resistor on the DAT3 line may be used for card detection (insertion/removal). The resistor can

be disconnected during data transfer (using ACMD42). Additional practical card detection methods can be found in

SD Physical Specification’s Application Notes given by the SDA.

1.5.9.4. Card Status

The card status is separated into the following two fields:

• Card Status is stored in a 32-bit status register that is sent as the data field in the card respond to host

commands. Status register provides information about the card’s current state and completion codes

for the last host command. The card status can be explicitly read (polled) with the SEND_STATUS

command.

• SD_Status is stored in 512 bits that are sent as a single data block after it was requested by the host

using the SD_STATUS (ACMD13) command. SD_STATUS contains extended status bits that relate

to BUS_WIDTH, security related bits and future specific applications.