A display driver integrated circuit includes a first slave module and a second slave module. The first slave module is initially set as a primary module to receive a mode conversion command, and is disabled based on the mode conversion command. The second slave module is initially set as a secondary module that does not receive the mode conversion command, and is set as the primary module instead of the first slave module when the first slave module is disabled. The first and second slave modules control processing or transfer of data through a channel included in or coupled to a display according to a predetermined protocol.