Renesas SH7781 - Manual (Page 1240)

24. Multimedia Card Interface (MMCIF)
Rev.1.00 Jan. 10, 2008 Page 1210 of 1658
REJ09B0261-0100
(1) Operation of Broadcast Commands
CMD0, CMD1, CMD2, and CMD4 are broadcast commands. These commands and the CMD3
command comprise a sequence assigning relative addresses to individual cards. In this sequence,
the CMD output format is open drain, and the command response is wired-OR. During the
issuance of this command sequence, the transfer clock frequency should be set to a sufficiently
low value.
• All cards are initialized to the idle state by CMD0.
• The operation condition registers (OCR) of all cards are read via wired-OR and cards that
cannot operate are deactivated by CMD1.
The cards that are not deactivated enter the ready state.
• The card identifications (CID) of all cards in the ready state are read via wired-OR by CMD2.
Each card compares it's CID and data on the MMCCMD, and if they are different, the card
aborts the CID output. Only one card in which the CID can be entirely output enters the
acknowledge state. When the R2 response is necessary, set CTOCR to H'01.
• A relative address (RCA) is given to the card in the acknowledge state by CMD3.
The card to which the RCA is given enters the standby state.
• By repeating CMD2 and CMD3, RCAs are given to all cards in the ready state to make them
enter the standby state.
(2)
Operation of Relative Address Commands
CMD7, CMD9, CMD10, CMD13, CMD15, CMD39, and CMD55 are relative address commands
that address the card by RCA. The relative address commands are used to read card administration
information and original information, and to change the specific card states.
CMD7 sets one addressed card to the transfer state, and the other cards to the standby state. Only
the card in the transfer state can execute flash-memory operation commands, other than broadcast
or relative-address commands.