Dallas Semiconductor Corporation

Joseph P Gorski

Edward Tangkwai Ma

Stephen N Grider

Edward Tang Kwai Ma

Frank V Taylor, Iii

Andrew D Jones

Ann Little

Methods, systems, and arrangements enable efficient reprogramming of a memory block of a microcontroller. Two blocks of memory each have a different logical location with respect to a processor of the microcontroller. The first memory may store vector information to be executed by the processor. The second memory may store data information. The logical location of each memory block is dependent on the value of a pre-determined bit in a specified register. When a user wishes to reprogram the contents of the first memory, the user enters new code into the second memory. Upon completion, the value of the pre-determined bit is changed, and the logical locations of the first and second memories are interchanged. In effect, the newly entered code from the second memory is accessed as if it were in the first memory (e.g., from an addressing perspective), and the processor may execute the new program (e.g., after the processor undergoes a system reset).

Memory exchange

A microcontroller and method for executing instructions from an 8051 instruction set are disclosed. The microcontroller includes first and second input/output (I/O) ports that are controlled such that the first I/O port is a dedicated data port and the second I/O port is a dedicated address port for performing memory cycles to external memory when in a page mode of operation. In addition, the cycle times of memory cycles to external memory is configurable so that the microcontroller is capable of more efficiently cooperating with both high speed and low speed external memory devices.

Microcontroller programmable method for accessing external memory in a page mode operation

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Plano, TX, United States of America

Joseph P Gorski