OpenBus Component Placement
Placement of OpenBus components is simply a case of clicking the required entry in the OpenBus Palette panel, positioning at the desired location in the workspace, and clicking again to effect placement. Familiar schematic placement controls, such as flipping and rotating allow for fine tuning as needed.
Although each OpenBus component has a designator, it is not a designator in the schematic sense of the word. There is no notion of annotation in the OpenBus System document. Rather, it is simply unique comment text. This text will initially be the name of the component as used in the schematic world, along with a suffix to distinguish multiple instances (e.g. WB_FPU_1).
Figure 1. Example designator.
Change this text to a more meaningful descriptor as required, but make sure the text of multiple instances of the same component are unique.
Bus Interface Ports
When an OpenBus component is placed, you will notice red and/or green circular appendages. These are referred to as OpenBus ports and represent the bus interface(s) of the component:
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| – | a red port represents a master bus interface |
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| – | a green port represents a slave bus interface |
A processor for example has two master ports, representing its Peripheral I/O and External Memory interfaces. The majority of peripherals have a single slave port. Some, like the VGA Controllers, have an additional master port, providing an interface to external memory.
Figure 2. Example OpenBus components and their ports.