Patent ID: 7421518

Claim:
A method of performing data communication between a processor and an external device, the processor having a central processing unit (CPU), a first interface connected to the external device to transfer data between the processor and the external device, and a second interface connected to the external device to control the external device, the method comprising: using the CPU, communicably connected to the first interface and the second interface, to set a communication parameter in one of the first interface and the second interface, by transferring said communication parameter over a first data bus; transferring said communication parameter from said one of the first interface and the second interface to the other of the first interface and the second interface over a second data bus without intervention by the CPU; transferring said communication parameter from the second interface to the external device; said second data bus being separate from said first data bus and being used only for the transfer of said communication parameter between said first interface and second interface; and transferring said data between the CPU and the external device over said first data bus, and through the first interface according to said communication parameter.