Product manual

5-4 SanDisk miniSD Card Product Manual, Rev. 1.1 © 2003 SANDISK CORPORATION
Every data block has a prefix or ‘start block’ token (one byte). After a data block is received the card will respond
with a data-response token, and if the data block is received with no errors, it will be programmed. As long as the
card is busy programming, a continuous stream of busy tokens will be sent to the host (effectively holding the
dataOut line low).
Once the programming operation is completed, the host must check the results of the programming using the
SEND_STATUS command (CMD13). Some errors (e.g., address out of range, write protect violation, etc.) are
detected during programming only. The only validation check performed on the data block and communicated to the
host via the data-response token is CRC and general Write Error indication.
In multiple-block write operations, the stop transmission is done by sending, at the beginning of the next block, a
Stop Tran token, instead of a Start Block token. In case of Write Error indication (on the data response) the host
shall use SEND_NUM_WR_BLOCKS (ACMD22) in order to get the number of well written write blocks. The data
token’s description is given in Section 5.2.4.
From
Host to
Card
From
Card to
Host
Host to Car
Stop
Tran
Token
DataIn
DataOut
Command
Busy
Data From
d
Data_
Response
Busy
Data
Response
and Busy
From Card
Response
Data
Block
Data
Block
Data_
Response
Busy
Start
Block
Token
Data From
Host to Card
Figure 5-5. Multiple Block Write Operation
Resetting the CS signal while the card is busy does not terminate the programming process. The card releases the
dataOut line (tristate) and continues to program. If the card is reselected before the programming is done, the
dataOut line will be forced back to low and all commands will be rejected.
Resetting a card (using CMD0) will terminate any pending or active programming operation. This may destroy the
data formats on the card. It is the host’s responsibility to prevent it.
5.1.5. Erase and Write Protect Management
The erase and write protect management procedures in the SPI mode are identical to the SD Bus mode. While the
card is erasing or changing the write protection bits of the predefined sector list it will be in a busy state and will
hold the dataOut line low. Figure 5-6 illustrates a “no data” bus transaction with and without busy signaling.