Disc drive controller to detect defects in read/write circuits for a disc drive

A disc drive controller for controlling the access of data provided between a disc drive and said controller, said disc drive controller comprising:

• a buffer circuit to buffer the data accessed between said disc drive and said controller;
• a write circuit, coupled between said buffer circuit and said disc drive to provide data to said disc drive, said write circuit further comprising a modulation circuit to modulate the data provided to said disc drive, and a write bypass circuit to provide data to said disc drive without being modulated;
• a read circuit coupled between said buffer circuit and said disc drive to read the data provided by said disc drive and to provide said read data to said buffer circuit, said read circuit further comprising a demodulation circuit to demodulate the data read from said disc drive;
• and
• a defect detecting circuit to detect the occurrence of a defect in said read circuit by comparing data which has been provided to said disc drive by said write bypass circuit and demodulated by said read circuit with a predetermined value.

A disc drive controller for controlling the access of data provided between a disc drive and said controller, said disc drive controller comprising:

• a buffer circuit to buffer the data accessed between said disc drive and said controller;
• a write circuit, communicatively coupled between said buffer circuit and said disc drive, wherein said write circuit provides serial data from said buffer circuit as parallel data to said disc drive, said write circuit operates in one of a modulated mode and a write-bypass mode to provide parallel modulated data and parallel unmodulated data, respectively;
• a read circuit communicatively coupled between said buffer circuit and said disc drive wherein one of said parallel modulated and write-bypass data provided to said disc drive by said write circuit is read by said read circuit and provided as serial data to said buffer circuit said read circuit operates in one of a demodulated mode and a read-bypass mode to provide said read-out serial data as demodulated data and as data without being demodulated respectively;
• and
• a defect detecting circuit to detect the occurrence of a defect in one of said write and read circuits, wherein said defect detecting circuit determines said write circuit is defective by comparing modulated dam provided to said disc drive by said write circuit and read by said read circuit according to the read-bypass mode with a predetermined value, and wherein said defect detecting circuit determines said read circuit is defective by determining whether write-bypass data provided to said disc drive by said write circuit can be demodulated by said read circuit.

A disc drive controller for controlling the transfer of data provided between a computer and a disc drive coupled to said computer, said disc drive controller comprising:

• a buffer circuit to buffer the data accessed between said disc drive and said controller;
• a signal providing circuit that provides a control signal to said buffer circuit;
• a memory device, coupled to said buffer circuit, that stores data;
• a write circuit, communicatively coupled between said buffer circuit and said disc drive wherein said write circuit provides serial data from said buffer circuit as parallel data to said disc drive in one of a modulated mode and a write-bypass mode;
• a read circuit communicatively coupled between said buffer circuit and said disc drive wherein one of said parallel modulated and write-bypass data provided to said disc drive by said write circuit is read by said read circuit and provided as serial data to said buffer circuit in one of a demodulated mode and a read-bypass mode;
• and
• a defect detecting circuit to detect the occurrence of a defect in one of said write and read circuits in response to said control signal, wherein said defect detecting circuit determines said write circuit is defective by comparing modulated data provided to said disc drive by said write circuit when said write circuit is in said modulated mode and read by said read circuit according to the read-bypass mode with a predetermined value, and wherein said defect detecting circuit determines said read circuit is defective by determining whether write-bypass data provided to said disc drive by said write circuit when said write circuit is said write bypass mode can be demodulated by said read circuit.