Controller, data storage device, and data communication system having variable communication speed

An apparatus comprising:

• a controller configured to:
• receive a signal from a host, the signal being compatible with a data communication protocol at a first data communication speed and indicative of a data communication speed;
• selectively, based on the determined data communication speed, implement a first data communication protocol from a plurality of data communication protocols to communicate with a first memory when the determined data communication speed is a first speed;
• selectively, based on the determined data communication speed, implement a second data communication protocol from the plurality of data communication protocols to communicate with a second memory when the determined data communication speed is a second speed that is different than the first speed;
• store data in the first memory via the first data communication protocol when the data communication speed is the first speed, the first memory distinct from the host;
• and
• store data in the second memory via the second data communication protocol when the data communication speed is the second speed, the second memory distinct from the host.

An apparatus comprising:

• a controller configured to:
• receive a signal from a host, the signal being compatible with a data communication protocol at a first data communication speed;
• detect a data communication speed based on the signal;
• selectively, based on the determined data communication speed, implement a first data communication protocol from a plurality of data communication protocols to communicate with a first memory when the determined data communication speed is a first speed;
• selectively, based on the determined data communication speed, implement a second data communication protocol from the plurality of data communication protocols to communicate with a second memory when the determined data communication speed is a second speed that is different than the first speed;
• store data in the first memory via the first data communication protocol when the detected data communication speed is the first speed, the first memory distinct from the host;
• and
• store data in the second memory via the second data communication protocol when the detected data communication speed is the second speed, the second memory distinct from the host.