BUS Arbitration

When multiple devices are connected to a single system BUS, there may arise a situation where multiple devices may request to access the BUS at the same time. This can create a clash between the devices and may result in data loss or system failure. To avoid such situations, we use BUS Arbitration.

BUS Arbitration is a mechanism that allows multiple devices to access the system BUS without any conflicts. It resolves the clash over the access of the system BUS by allowing only one device to access it at a time. The device which gets the access is called the BUS Master.

How does BUS Arbitration work?

BUS Arbitration works by allowing only one device to access the system BUS at a time. The arbitration process involves the following steps:

1. Request Phase: When a device needs to access the system BUS, it sends a request signal to the BUS Arbitrator.

2. Arbitration Phase: The BUS Arbitrator receives the request signals from all the devices and selects the highest priority device based on a pre-defined priority scheme. The selected device is granted the access to the BUS by the BUS Arbitrator.

3. Grant Phase: The selected device is granted the access to the BUS and it becomes the BUS Master. It can now transfer data to or from other devices connected to the BUS.

4. Release Phase: Once the BUS Master completes its data transfer, it releases the BUS and the next device in the priority list can access the BUS.

Conclusion

BUS Arbitration is an important mechanism to avoid clashes between devices when they access the system BUS. It helps in maintaining the integrity of the system and ensures smooth data transfer. By using BUS Arbitration, we can ensure that only one device accesses the BUS at a time, and the priority-based selection process ensures that high-priority devices get preference over low-priority devices.