Patent ID: 6253281
Filing Date: 2001-06-26
Classification: G06F,G11B,G11C

Abstract:
A method for updating program code contained in non-volatile memory for a microcontroller which controls the operation of an optical disk drive connected to a host computer, the method comprising the steps of:providing in a protected non-erasable area of the non-volatile memory, first program code for performing an integrity check of second program code in an unprotected rewritable area of the non-volatile memory and requesting and receiving updated second program code from the host computer;providing in a read only memory (ROM) contained in the microcontroller, third program code for erasing data from and writing data to the unprotected rewritable area of the non-volatile memory;checking the integrity of the second program code, and if the integrity check fails then:requesting the host computer to supply updated second program code;receiving the updated second program code into random access memory (RAM) within the disc drive;erasing second program code from at least a selected portion of the unprotected area of the non-volatile memory; andwriting the updated second program code from the RAM into at least the selected portion of the unprotected rewritable area of non-volatile memory.