OpenBus Tutorial - Configuring the Arbiter Components

Configuration of an Arbiter component in the OpenBus System is also a more streamlined process, in relation to its schematic-based counterpart, WB_MULTIMASTER. The system again handles much of the configuration for you, so information such as data and address bus widths no longer require user-definition.

Only two pieces of information are required through the dialog to configure the Arbiter – the access Type and the Master With No Delay.

1. Double-click on the Arbiter component to access the Configure OpenBus Arbiter dialog.
    
2. In the Type region of the dialog, ensure that the Priority option is selected. In this mode of access, masters access the slave in strict sequence, starting with the master connected to port s0 (highest priority).
    

3. In the Master With No Delay region of the dialog, ensure that port s0 is selected. As we have connected the VGA Controller to port s0 of the Arbiter component, we need to ensure it is nominated to be the master without delay – receiving instant access to the memory when the Arbiter is in an 'idle' state.
    
   

   Figure 1. Configured Arbiter component.

The master with no delay is distinguished graphically on the Arbiter component by use of red text for its port number. In our system, slave port s0 is the master with no delay, and so its port number text – 0 – appears in red.

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