Datasheet

751
SAM9263 [DATASHEET]
Atmel-6249N-ATARM-SAM9263-Datasheet_14-Mar-16
The command ALL_SEND_CID and the fields and values for the MCI_CMDR are described in Table 39-4 and
Table 39-5.
Note: bcr means broadcast command with response.
The MCI_ARGR contains the argument field of the command.
To send a command, the user must perform the following steps:
 Fill the argument register (MCI_ARGR) with the command argument.
 Set the command register (MCI_CMDR) (see Table 39-5).
The command is sent immediately after writing the command register. The status bit CMDRDY in the status
register (MCI_SR) is asserted when the command is completed.
While the card maintains a busy indication (at the end of a STOP_TRANSMISSION command CMD12, for
example), a new command shall not be sent. The NOTBUSY flag in the status register (MCI_SR) is asserted when
the card releases the busy indication.
If the command requires a response, it can be read in the MCI response register (MCI_RSPR). The response size
can be from 48 bits up to 136 bits depending on the command. The MCI embeds an error detection to prevent any
corrupted data during the transfer.
The following flowchart shows how to send a command to the card and read the response if needed. In this
example, the status register bits are polled but setting the appropriate bits in the interrupt enable register
(MCI_IER) allows using an interrupt method.
Table 39-4. ALL_SEND_CID Command Description
CMD Index Type Argument Response Abbreviation Command Description
CMD2 bcr [31:0] stuff bits R2 ALL_SEND_CID Asks all cards to send their CID numbers on the CMD line
Table 39-5. Fields and Values for MCI_CMDR Command Register
Field Value
CMDNB (command number) 2 (CMD2)
RSPTYP (response type) 2 (R2: 136 bits response)
SPCMD (special command) 0 (not a special command)
OPCMD (open drain command) 1
MAXLAT (max latency for command to response) 0 (NID cycles ==> 5 cycles)
TRCMD (transfer command) 0 (No transfer)
TRDIR (transfer direction) X (available only in transfer command)
TRTYP (transfer type) X (available only in transfer command)
IOSPCMD (SDIO special command) 0 (not a special command)