HyperTransport™ System Architecture

The Error Types

The following section summarizes the required CRC generation/checking as well as the optional protocol, receive buffer overflow, end of chain, chain down, and response error handling.

CRC Errors

The Cycle Redundancy Code (CRC) is used to detect transmission errors on all enabled byte lanes on each link. The 32 bit CRC value is calculated and sent at prescribed intervals by each transmitter, then checked against the CRC value calculated by the corresponding receiver as packets arrive. CRC is calculated by finding the remainder when the sum of packet data (CAD bits plus CTL signal during each bit time) is divided by the CRC polynomial. The polynomial used is:

X³² + X²⁶ + X²³ + X²² +X¹⁶ + X¹² + X¹¹ + X¹⁰ +X⁸ +X⁷ +X⁵ +X⁴ +X² + X +1 ...