19.3.2 Special Bus Granting Mechanism

The MATRIX provides some speculative bus granting techniques in order to anticipate access requests from Hosts. This technique reduces latency at the first access of a burst, or for a single transfer, as long as the Client is free from any other Host access. Bus granting sets a different default Host for every Client.

At the end of the current access, if no other request is pending, the Client remains connected to its associated default Host. A Client can be associated with three kinds of default Hosts:

• No default Host
• Last access Host
• Fixed default Host

To change from one type of default Host to another, the MATRIX user interface provides the Client Configuration registers, one for every Client, that set a default Host for each Client. The Client Configuration register contains the fields DEFMSTR_TYPE and FIXED_DEFMSTR. The 2-bit DEFMSTR_TYPE field selects the default Host type (no default, last access Host, fixed default Host), whereas the 4-bit FIXED_DEFMSTR field selects a fixed default Host provided that DEFMSTR_TYPE is set to fixed default Host. Please refer to the "Bus Matrix Client Configuration Registers" section.