Siemens
Product Manual R0008
Semiconductor Group
20
3.1
mon denominator for operation and notify the application that cards with out of range parameters
(from the host perspective) are connected to the bus. Incompatible cards go into Inactive State
After an operating mode is established, the host asks all cards for their unique card identification
(CID) number with the broadcast command ALL_SEND_CID (CMD2). All not already identified
cards (i.e. those which are in Ready State) simultaneously start sending their CID numbers serially,
while bit-wise monitoring their outgoing bit stream. Those cards, whose outgoing CID bits do not
match the corresponding bits on the command line in any one of the bit periods, stop sending their
CID immediately and must wait for the next identification cycle (cards stay in the Ready State).
There should be only one card which successfully sends its full CID-number to the host. This card
then goes into the Identification State The host assigns to this card (using CMD3,
SET_RELATIVE_ADDR) a relative card address (RCA, shorter than CID), which will be used to
address the card in future communication (faster than with the CID). Once the RCA is received the
card transfers to the Standby Stateand does not react to further identification cycles. The card also
switches the output drivers from the open-drain to the push-pull mode in this state.
The host repeats the identification process as long as it receives a response (CID) to its identifica-
tion command (CMD2). When no card responds to this command, all cards have been identified.
The time-out condition to recognize this, is waiting for the start bit for more than 5 clock periods after
sending CMD2.
6.3
Operating voltage range validation
The MultiMediaCard standards operating range validation is intended to support reduced voltage
range MultiMediaCards. The R0008 supports the full range of 2.0 to 3.6V supply voltage. So the
R0008 sends a R3 response to CMD1 which contains an OCR value of 0xFFFFFFFF (see"Chapter
6.5: Responses").
6.4
Data transfer mode
When in Standby State, both CMD and DAT lines are in the push-pull mode. As long as the content
of all CSD registers is not known, the f
PushPull
clock rate is equal to the slow f
OpenDrain
clock rate.
SEND_CSD (CMD9) allows the host to get the Card Specific Data (CSD register), e.g. ECC type,
block length, card storage capacity, maximum clock rate etc.
Figure 5: R0008 state diagram (data transfer mode)
State (tran)
Stand-by State
(stby)
Transfer
Sending-data
State (data)
CMD3
CMD4,
9,10
CMD7
CMD 16
CMD7
data transfer mode
card identification mode
CMD13
in data-transfer-mode
no state transition
CMD12,
“operation
complete”
CMD15
from all states in
data-transfer-mode
CMD0
CMD11,17,18