15.08.2013 Views

DESIGN OF A CUSTOM ASIC INCORPORATING CAN™ AND 1 ...

DESIGN OF A CUSTOM ASIC INCORPORATING CAN™ AND 1 ...

DESIGN OF A CUSTOM ASIC INCORPORATING CAN™ AND 1 ...

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

Figure 4.3 Centralized arbiter with two priority levels (four devices) [38].<br />

In decentralized arbitration schemes, priority-based arbitration is usually used in a<br />

distributed fashion without the need of a central arbiter as shown in Figure 4.4. Each potential<br />

master has a unique arbitration number, which is used in resolving conflicts when multiple<br />

requests are submitted [38]. A device that wants to become a bus master first asserts the bus<br />

Request Level line, and then it checks if the bus is busy. If the Bus Busy line is not asserted,<br />

then the device sends a “0” to the next higher numbered device on the daisy chain, asserts the<br />

Bus Busy line, and de-asserts the Request Level line. If the bus is busy, or if a device does not<br />

want the bus, then it simply propagates the bus grant to the next device.<br />

Figure 4.4 Decentralized bus arbitration [38].<br />

84

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!