Method and apparatus for selectively terminating signals on a bidirectional bus based on bus speed

摘要

A method of controlling signal termination includes providing first logic for selectively terminating signals received at a first device on a bidirectional data bus, providing second logic for selectively terminating signals received at a second device on the bidirectional data bus, sending first signals from the first device to the second device on the bidirectional data bus at a first speed, stopping the sending of the first signals, after stopping the sending of the first signals, enabling the second logic and shifting a reference voltage of the second device from a first level to a second level, after enabling the second logic at the second device, sending second signals from the first device to the second device on the bidirectional data bus at a higher speed, and controlling the first logic based on a speed of signals received at the first device on the bidirectional data bus.

主权项

1. A method of controlling signal termination on at least one bus connecting a first device to a second device, the method comprising:
connecting the first device to the second device by a bidirectional data bus; providing first termination logic for selectively terminating signals received at the first device on the bidirectional data bus; providing second termination logic for selectively terminating signals received at the second device on the bidirectional data bus; sending first signals from the first device to the second device on the bidirectional data bus at a first speed; after the sending of the first signals, enabling the second termination logic and shifting a reference voltage of the second device from a first level to a second level; after enabling the second termination logic at the second device, sending second signals from the first device to the second device on the bidirectional data bus at a second speed, greater than the first speed; and controlling the first termination logic based on a speed of signals received at the first device on the bidirectional data bus.