Abstract: A method for dynamically adjusting an operating speed of a microprocessor for the microprocessor to access at least a serial flash memory(together with a random access memory). The method includes reducing an executing speed of the microprocessor if the required data in the serial flash memory (or the random access memory) is not well prepared and executing the microprocessor at a normal speed if the required data in the serial flash memory(or the random access memory) is well prepared.

Abstract: A method for accessing a memory having a storage space larger than the addressing capability of a microprocessor. The method comprises storing an interrupt service routine in one of a plurality of memory banks, when an interrupt occurs, pushing a current program counter address onto a stack by an interrupt processing unit, and pushing a bank number of the current memory bank onto the stack. The method further comprises switching the microprocessor to the memory bank storing the interrupt service routine to execute the interrupt service routine, popping the bank number of the memory bank from the stack, restoring the popped bank number in the memory bank selector, popping the program counter address from the stack, and continuing executing the interrupted program.

Abstract: A microcontroller with expandable memory banks has a microprocessor, a plurality of memory banks with only one page for storing interrupt service routines(ISR), a memory bank control circuit connected to the microprocessor, and a multiplexer for connecting the microprocessor with the plurality of memory banks. The memory bank control circuit generates a selection signal according to an interrupt signal and a microprocessor interrupt service routine execution end signal. The multiplexer outputs a page selection signal from the microprocessor or outputs a predetermined page selection signal according to the output signal from the memory bank control circuit.

Abstract: A method for increasing the internal memory in a processor. The method includes providing an extended memory in the processor, adding bits to data addresses and register addresses with an address extender, and adding bits to stack addresses with a stack pointer generator so that the processor is capable of accessing memory addresses larger than the bit width of the command set of the processor. The method also includes carrying over the bits when the stack address exceeds the limit of the conventional memory and accessing the stack data exceeding the limit of the conventional memory in the extended memory.

Abstract: A processor includes a CPU, a data memory, a stack memory, a memory address generator, and a stack pointer generator. The CPU is used to process data and instructions. The data memory is used to store non-stack data. The stack memory is used to store stack data. The memory address generator is used to generate addresses for accessing the data memory. The stack pointer generator is used to generate pointers for accessing the stack memory.

Abstract: A control chip for updating firmware in an optical disk drive by hardware. The control chip includes a microprocessor for controlling actions of the optical disk drive, a decoder controlled by the microprocessor and connected to an external buffer memory and a host interface, a controller controlled by the microprocessor and connected to the decoder to receive control signals and data of the optical disk drive, an extra memory connected to the microprocessor for storing an update program routine, a DMA unit controlled by the microprocessor to read data from the external buffer memory, and a macro unit controlled by the microprocessor to receive data output from the DMA unit and to write the data into the non-volatile memory. Because the firmware is updated into the flash memory in the hardware architecture, the speed is fast and the microprocessor can execute other works while updating.

Abstract: An update method is used in an optical disk system to update firmware information stored in a firmware memory. The method includes fetching program code and an update program routine from an update source, storing the program code into a first buffer, storing the update program routine into a second buffer, executing the update program routine stored in the second buffer, writing the program code stored in the first buffer into the firmware memory to update the firmware information, and changing a value of a program counter of the microprocessor such that the microprocessor executes the program code stored in the firmware memory at a predetermined location of the program code instead of executing a next instruction in the program code located after the current position of the program counter, and using the program code as updated firmware information to control the optical disk system.