HyperTransport™ System Architecture

Example: Initialization And Use Of The Counters

The following three diagrams and associated descriptions explain the initialization of HyperTransport buffer counts, followed by the actions taken by the transmitter and receiver as two packets are sent across the link. The diagrams have been simplified to show a single flow control buffer and the corresponding receiver and transmitter counters used to track available entries. In this example, assume the following:

• The flow control buffer illustrated is the Posted Request Command (CMD) buffer.

• The designer of the receiver interface has decided to construct this flow control buffer with a depth of five entries. Because this is a buffer for receiving requests, each entry in the buffer will hold up ...