July 2008
Intermediate to advanced
544 pages
16h 52m
English
Content preview from Computers as Components, 2nd Edition
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154 CHAPTER 4 Bus-Based Computer Systems
defines a protocol by which the CPU, memory, and devices communicate. One of
the major roles of the bus is to provide an interface to memory. (Of course, I/O
devices also connect to the bus.) Based on understanding of the bus, we study the
characteristics of memory components in this section.
4.1.1 Bus Protocols
The basic building block of most bus protocols is the four-cycle handshake,
illustrated in Figure 4.1. The handshake ensures that when two devices want to
communicate, one is ready to transmit and the other is ready to receive. The hand-
shake uses a pair of wires dedicated to the handshake: enq (meaning ...