Patent ID: 7915924

Claim:
A mode detector, comprising: a NOR gate for receiving a first input clock and a second input clock and for generating a first output therefrom; a first latch having a first reset terminal for receiving said first output, a first clock terminal for receiving a clock signal, a first data terminal for receiving a fixed voltage signal thereon, and a first output terminal for conveying a second output generated by said first latch; a second latch connected in series with said first latch and having a second reset terminal for receiving a system reset signal, a second clock terminal for receiving said clock signal, a second data terminal connected to said first output terminal for receiving said second output, and a second output terminal for conveying a third output generated by said second latch; a third latch having a third reset terminal for receiving said first output, a third clock terminal for receiving said clock signal, a third data terminal for receiving a fixed voltage signal thereon, and a third output terminal for conveying a fourth output generated by said third latch; a fourth latch connected in series with said third latch and having a fourth reset terminal for receiving said system reset signal, a fourth clock terminal for receiving said clock signal, a fourth data terminal connected to said third output terminal for receiving said fourth output, and a fourth output terminal for conveying a fifth output generated by said fourth latch; and a NAND gate for receiving said third and said fifth outputs as inputs thereto and for generating a mode signal at an output thereof.