MICROCONTROLLER ARCHITECTURE

MICROCONTROLLER ARCHITECTURE
                
                   There are two types of MICROCONTROLLER architectures. They are
                                      1. von Neumann
                                       2. Harvard

          1. Von Neumann Architecture

                             The von Neumann architecture allows for one instruction to be read from memory or data to be read/written from/to memory at a time. In other words, an instruction fetch and data operation cannot be performed at the same time. Instructions and data are stored in the same memory subsystem and share a communication pathway or bus to the CPU.

        2. Harvard Architecture

                                       The Harvard architecture alternatively consists of separate pathways or buses for interaction between the CPU and memory. The separation allows for instructions and data to be accessed concurrently. Also, a new instruction may be fetched from memory at the same time another one is finishing execution, allowing for a primitive form of pipelining. Pipelining decreases the execution time of one instruction, but main memory access time, in many cases, is a major bottleneck in the overall performance of the system.