Method for reprogramming flash ROM in a personal computer implementing an EISA bus system

A method for erasing a portion of a sector in a flash ROM device, which is included in a PC system that includes RAM, wherein the sector includes at least two different programs, one of which is to be erased, the method comprising the steps of:

• (a) detecting an erase function request to said sector of said flash ROM;
• (b) placing the flash ROM in a Command Mode;
• (c) determining the location of the program resident in the sector which is to be erased;
• (d) reading the portion of the sector containing other programs and copying that portion to RAM;
• (e) erasing the sector;
• and
• (f) rewriting the portion of the sector which was copied to RAM back to the sector in the flash ROM.

A personal computer comprising:

• an EISA bus system;
• a central processing unit connected to the EISA bus system;
• at least one expansion slot connected to said EISA bus system for accommodating an EISA expansion board;
• a random access memory (RAM) connected to said EISA bus system;
• and
• a flash ROM connected to said EISA system bus, said flash ROM including a plurality of memory sectors on which codes are stored, and wherein one of said memory sectors stores both EISA configuration code and boot code;
• means for monitoring interrupt routines for erase functions to the EISA configuration code stored in the flash ROM;
• and
• means for transferring the boot code to the RAM before erasing the memory sector containing the EISA configuration code and the boot code.

A method of reprogramming a flash ROM that includes a multi-sector memory array having boot code and EISA configuration code stored in the same sector of the ROM's memory array, the method comprising the steps of:

• (a) installing a new Interrupt 15 routine in place of an old Interrupt 15 routine;
• (b) executing the new Interrupt 15 routine whenever an Interrupt 15 is requested;
• (c) monitoring the Interrupt 15 request for an erase or write function;
• and
• (d) executing an erase or write routine in response to the presence of an erase or write function.

A method of reprogramming EISA configuration code in an AMD flash ROM device, wherein the flash ROM is divided into eight memory array sectors, and said EISA configuration code is stored in sector 7 of the flash ROM together with boot code and Ediags instruction code, said method comprising the steps of:

• (a) initializing an Interrupt 15 routine;
• (b) determining if the flash ROM comprises an AMD flash ROM;
• (c) modifying the Interrupt 15 routine in response to an affirmative determination in step b;
• (d) monitoring Interrupt 15 requests for the presence of an erase or a write function to EISA configuration code;
• (e) entering a 32 bit protective mode in response to the presence of an erase or write function in the Interrupt 15 request;
• (f) placing the AMD flash ROM in a Command Mode by transmitting a sequence of command signals to various addresses in the flash ROM device;
• (g) erasing or writing to the EISA configuration code in sector 7.