h8s-2158 Renesas Electronics Corporation., h8s-2158 Datasheet - Page 708

• Manufacturer Part Number: h8s-2158
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family/h8s/2100 Series
• Manufacturer: Renesas Electronics Corporation.

Section 19 Multimedia Card Interface (MCIF)
19.5
MMC mode is an operating mode in which the transfer clock is output from the MCCLK pin,
command transmission/response receive occurs via the MCCMD pin, and data is
transmitted/received via the MCDAT pin. In this mode the next command can be issued while data
is being transmitted/received. This feature can be applied to the multiblock transfer and stream
transfer in which the number of bytes for data transfer does not need to be specified beforehand. In
this case, the next command is the CMD12 command, which aborts the current command
sequence.
In MMC mode, a broadcast command that simultaneously issues a command to multiple MMCs is
supported. After the information for the MMC that is inserted by using the broadcast command is
acknowledged, a relative address is given to each MMC. One MMC is selected by the relative
address, other MMCs are deselected, and various commands are issued to the selected MMC.
19.5.1
The CMD0, CMD1, CMD2M, and CMD4M are broadcast commands. The command sequence
assigning relative addresses to individual MMCs consists of these commands and the CMD3M
command. In this command sequence, the CMD output format of the MMC side is open drain, and
the command response is wired-OR. During the issuance of this command sequence, the transfer
clock frequency should be set sufficiently slow. Operation of a typical command is summarized
below.
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REJ09B0286-0300
All MMCs are initialized to the idle state by CMD0.
The operation condition register (OCR) of all MMCs is read by CMD1 via wired-OR, and
MMCs that cannot operate are deactivated. The deactivated MMCs enter the ready state.
The card identification (CID) of all MMCs in the ready state is read by CMD2M via wired-
OR. The individual MMC compares its CID and data on the CMD, and if different, aborts CID
output. A single MMC in which the CID can be entirely output enters the acknowledge state.
A relative address (RCA) is given to the MMC in the acknowledge state by the CMD3M.
The MMC to which the RCA is given enters the standby state.
CMD2M and CMD3M are repeated, assigning RCAs to all MMCs in the ready state, entering
each into the standby state.
Operations in MMC Mode
Operation of Broadcast Commands