diff -r 578be2adaf3e -r 307f4279f433 Adaptation/GUID-C059F39F-BC53-5C92-B05E-863B8CF22859.dita --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/Adaptation/GUID-C059F39F-BC53-5C92-B05E-863B8CF22859.dita Fri Oct 15 14:32:18 2010 +0100 @@ -0,0 +1,46 @@ + + + + + +Command +ObjectsThe MultiMediaCard controller uses a TMMCCommandDesc object +to contain command and parameter information when issuing a command over the +bus. +

This object is also used to contain response information resulting from +the execution of that command.

+

As it can sometimes be necessary to temporarily save current command and +parameter information, the controller implements a small stack of TMMCCommandDesc objects. +The controller then has the concept of a current command information +object.

+

The platform independent layer provides three functions through which command +and parameter information can be set up:

+ +

These functions are used to fill the current TMMCCommandDesc object.

+

The controller executes a single command by calling the state machine function DMMCStack::IssueMMCCommandSM(); +this is implemented by the platform specific layer as part of the porting +activity.

+

It calls DMMCSession::Command() to access the current command +and parameter information.

+
The command +stack

Internally, the command stack is implemented as a simple +array of TMMCCommandDesc objects; this is the DMMCSession::iCommand[] private +data member. The stack is KMaxMMCCommandStackDepth deep. +Internally, the current command information object is identified and accessed +through the DMMCSession::iCmdSP data member, which indexes +into the array and acts as a pointer to the current command information object.

The +platform independent layer provides two protected functions that the platform +specific layer can use to change the command information object that is current:

    +

  • DMMCStack::CurrentSessPushCmdStack()

    • +

  • DMMCStack::CurrentSessPopCmdStack()

    • +
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