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Home > Protocols > Peripheral protocols > MMC_Protocol protocol |
This protocol describes an abstract, untimed interface between an MMC controller and an MMC or SD card.
The protocol contains methods that must be implemented by the master (controller) and some that must be implemented by the slave (card). This protocol is used by the reference PL180 MCI and MMC models. for further information on the protocol implementation, see the source file, %PVLIB_HOME%\LISA\MMC_Protocol.lisa.
Use of this protocol assumes knowledge of the MultiMediaCard specification, available from the MultiMediaCard Association, www.mmca.org.
The protocol has these behaviors:
cmd
For data transfer in the card to controller direction:
Rx
Rx
behavior
on the controller to provide the read data. The call provides a
pointer and a length. The ARM MMC reference model simulates device
read latency by waiting a number of clock cycles prior to calling
this behavior. If the controller is unable to accept the data, or
wants to force a protocol error, it can return false in response
to this behavior.Rx_rdy
For data transfer in the controller to card direction:
Tx
Tx
behavior
on the controller. The call provides a pointer to an empty buffer
to be written, and a length. The ARM MMC reference model simulates
device write latency by waiting a number of clock cycles prior to
each buffer being offered.Tx_done
The card model must also implement:
cmd_name