Device including an external memory connection unit capable of adopting an external memory

A device comprising:

• a memory controller;
• a memory bus coupled to the memory controller;
• an internal memory directly connected to the memory controller through the memory bus;
• and
• an external memory connection snit configured to connect an external memory directly to the memory controller through a portion of signal lines in the memory bus, and configured to generate a flag signal indicating whether the external memory is connected to the external memory connection unit,
• wherein the internal memory communicates with the memory controller with a maximum data bus width in a base mode representing that the external memory is not connected to the external memory connection unit, and
• wherein the maximum data bus width is divided into a first data bus width and a second data bus width in a memory extension mode representing that the external memory is connected to the external memory connection unit such that the internal memory communicates with the memory controller with the first data bus width and the external memory communicates with the memory controller with the second data bus width.

A mobile device comprising:

• a system-on-chip including a memory controller;
• a memory bus coupled to the memory controller;
• an internal memory directly connected to the memory controller through the memory bus, the internal memory directly connected to the memory controller through signal lines of the memory bus;
• and
• an external memory connection unit configured to connect an external memory directly to the memory controller through a portion of the signal lines of the memory bus, and configured to generate a flag signal indicating whether the external memory is connected to the external memory connection unit.