Adding a Bus

This section focuses on adding a bus to the VisualSim model.

Adding??a Bus to the VisualSim Architecture Model

Figure 1: Enhancing the Basic VisualSim model with a BusArbiter

List of Additional Blocks

Sl No

Library Block

Description

BusArbiter

Hardware_Devices > Bus Arbiter

The Linear_Controller block is the Arbiter for a Linear Bus. The Linear bus is a shared bus topology with an arbiter.

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BusInterface

Hardware_Devices > BusInterface

The Linear_Port block is used to connect the devices to the Linear_Controller Bus. The block has a queue for each port. The incoming transactions are queued and the head of the queue is sent to the Controller Queue.

Click here for detailed description & examples.

Model Construction

Disconnect the DRAM.
Place the BusInterface and the BusArbiter one above the other.
Connect the left side of the BusInterface to the Processor and the right-side to the DRAM.

Execution

Re-run the simulation and review the results.

Notes

What is the difference between the Port and Controller?
What is the significance of the Port names and Bus name in the BusInterface block? Do they have to be unique?
If the devices are connected to a single BusInterface block, are they considered to be a direct connection?

Hint: No, it just means that they are connected to the same shared bus.

What is the purpose of the BusArbiter vs. the BusInterface?

Hint: The port has a queue for the connected device. The BusArbiter provides the arbitration.

Advanced topic - How do I modify the Bus arbitration algorithm used? Use the in/out ports on the right-side of the BusArbiter block.

AddingaBus

List of Additional Blocks

Model Construction

Execution

Notes