Patent ID: 7999816

Claim:
A video display apparatus that supports a display data channel (DDC) and is connectable to a host apparatus which provides an input video signal to the video display apparatus, comprising: a digital visual interface (DVI) connector to enable connection to an external display device; only one DDC-supported non-volatile memory; a switch circuit arranged between the DVI connector and the DDC-supported non-volatile memory, said switch circuit having a first terminal and a second terminal and being switchable therebetween; a data memory, separate from the DDC-supported non-volatile memory, to store extended display identification (EDID) data for a digital television broadcasting (DTV) video signal and EDID data for a RGB video signal; and a processing unit; said switch circuit being coupled to the DDC-supported non-volatile memory and said first terminal of the switch circuit being connected to the processing unit and said second terminal of the switch circuit being connected to the DVI connector, and during operation, (i) said processing unit determines whether the EDID data for the DTV video signal or the EDID data for the RGB video signal is to be supplied to the DDC-supported non-volatile memory, causes an appropriate one of the EDID data for the DTV video signal or the EDID data for the RGB video signal to be read out from the data memory and supplied by way of said first terminal to the DDC-supported non-volatile memory so as to be written therein, and then controls the switch circuit so as to connect the DDC-supported non-volatile memory to said second terminal such that the DDC-supported non-volatile memory is directly connected to the DVI connector, and (ii) when a kind of said input video signal supplied from the host apparatus has changed from the DTV video signal to the RGB video signal or from the RGB video signal to the DTV video signal after the EDID data corresponding to a previous input video signal had been written in the DDC-supported non-volatile memory, said processing unit causes the EDID data corresponding to a current input video signal to be read out from the data memory and written into said DDC-supported non-volatile memory such that the EDID data previously in the DDC-supported non-volatile memory is rewritten to that of the current input video signal, said processing unit determines whether the EDID data for the DTV video signal or the EDID data for the RGB video signal is to be supplied to the DDC-supported non-volatile memory through trial-and-error, such that when a video signal is input from the host the EDID data for the RGB video signal is supplied to the DDC-supported non-volatile memory, and when no video signal is input from the host the EDID data for the DTV video signal is supplied to the DDC-supported non-volatile memory.