Bus definitions are a part of the IP-XACT and they are used to define bus connections in HW designs.
Allow direct master-slave connection defines if a master bus interface can be directly connected to a slave bus interface. If unselected, a bus interface can be connected only to a mirrored bus interface of the same type e.g. master to mirrored-master.
Support broadcast defines if the bus interface using this definition can be connected to more than one opposing interface i.e. supports one-to-many connections.
Addressable bus defines if the bus interfaces contain addressing information.
Max masters on bus defines the maximum number of master bus interfaces connected to the bus. If unspecified, the number of masters is unbound.
Max slaves on bus defines the maximum number of slaves bus interfaces connected to the bus. If unspecified, the number of slaves is unbound.
System group names defines the group names available for signals with the system mode. In bus interface the selected system group limits the logical signals to those with the matching system group name.
Description is an optional free text for further details.
An abstraction definition can also be linked with a bus definition to provide additional validation for bus connections. Abstraction definition defines what logical signals must be present in the bus interface in order for the bus connection with such abstraction definition to be valid. Logical signals have the following properties:
Name is a mandatory unique identifier for the logical signal.
Mode defines for which interface mode the settings apply.
Presence is an optional restriction for the logical signal presence in a bus interface. It can have one of the following three values:
Direction is an optional restriction for the logical signal direction in the connected bus interface.
Width is an optional definition of the number of bits in the logical signal. If not specified, the number of bits in the connected physical port is used.
Default value is an optional value that is applied when the logical signal is not connected in a connected bus interface.
Driver is an optional setting for defining what kind of a driver the logical signal requires in a complete design. The possible values are the following:
Qualifier is an optional indicator for what kind of information the the signal carries. It can have one of the following five values:
System group helps identify the system interface the signal belongs to. System group is mandatory for system mode and illegal for other modes.
Description is an optional free text for further details.
Bus editor contains a context menu (right mouse button) that provides following options: