Nonvolatile memory card controller with an optimized memory address mapping window scheme

In a computer system having an integrated circuit card controller coupled to receive a nonvolatile memory card for controlling memory operation of the memory card, a method of locating a memory address of the memory card that corresponds to an external address, comprising the steps of:

• (A) accessing a first memory address mapping window for the memory address when external circuitry accesses the memory card with the external address, wherein the controller includes the first memory address mapping window and a second memory address mapping window, each storing one of a first set and a second set of memory addresses of the memory card, wherein the first and second set of memory addresses are configured to map the external address directly and through address translation;
• (B) if the first window has the memory address, then accessing the first window for the memory address;
• (C) if the first window does not have the memory address, then
• (i) accessing the second window for the memory address;
• (ii) updating the second window with a third set of memory addresses of the memory card if the second window does not have the memory address;
• (iii) switching the second window with the first window such that the second window becomes the first window and the first window becomes the second window and then returning to the step (A) until the memory address is accessed, wherein updates of the first and second windows are minimized.

A computer system, comprising:

• (A) a bus;
• (B) a central processing unit coupled to the bus;
• (C) an integrated circuit card controller coupled to the bus for controlling memory operation of a nonvolatile memory card coupled to the controller, wherein the controller further comprises
• (i) a first memory address mapping window configured to store a first set of memory addresses of the memory card;
• (ii) a second memory address mapping window configured to store a second set of memory addresses of the memory card, wherein both the first and second windows are readily accessible and are configured to map the external address directly and through address translation;
• (iii) circuitry configured to locate a memory address of the memory card that corresponds to an external address by accessing the first and second windows, wherein the circuitry for locating accesses the first window for the memory address when external circuitry accesses the memory card with the external address, wherein if the first window does not have the memory address, then the circuitry for locating accesses the second window for the memory address;
• (iv) circuitry configured to update the second window with a third set of memory addresses of the memory card if the second window also does not have the memory address;
• (v) circuitry configured to switch the second window with the first window such that the second window becomes the first window and the first window becomes the second window if the first window does not have the memory address, wherein updates of the first and second windows are minimized.