以Avalon Bus技術支援MC8051同步化多重I/O控制應用於乙太網路控制器之實現

Abstract

In recent years, with the process of embedded systems, microprocessors have been widely used on many applications such as smart phones, laptops, multi-media equipments, automatic control systems, robot controls, etc. For the microprocessors designed for embedded systems, it firstly considers the control capability and integration capability. In general, the microprocessor integrals many communication sequences (e.g., UART, SPI, I2C, Microwire, 1-wire), parallel peripherals (e.g., EMI, LBI, PCI Bus) and General Purpose I/O (GPIO). Ethernet network always is an applicable transmission method in certain applications such as real-time multi-media transfer, virtual network conference, high speed data transfer, etc. because of its easy to use, low cost, high bandwidth and high stability. In conclusion, the embedded Ethernet micro-controller is one of the future trends. Nowadays, the 8 bits micro-controllers still are the main product in Taiwan, and the 16 bits micro-controllers are the second one. The most typical 8 bits micro-controller is MC8051, because it sells 3.3 thousand million ones averagely in one year. MC8051 owns program memory with 4k bytes, data memory with 128 Bytes, 4 sets I/O ports and one single bus, so it can never be used to the application of controlling internet. Our search is to improve the limitation casing by the 4 sets I/O ports and one single bus in MC8051 and implement an Ethernet micro-controller which is low cost, easy to use and high adaptability. We proposed the Waiting State of MC8051 and two circuits called ramx Transfer Interface and Ethernet Transfer Interface, respectively. The waiting state can be inserted into the timing of MC8051 and keeps an idle state though the design of the Waiting State for MC8051. The control signals of external data memory model of MC8051 can be combined with Avalon bus though the design of ramx Transfer Interface. The synchronous and shared mechanism of Avalon allows MC8051 to realize synchronous and multiple I/O control. Then the synchronous and multiple I/O control can be integrated with DM 9000A Ethernet controller and realize the control capability of Ethernet through the design of Ethernet Transfer Interface. According to our analysis of packet processing rate, our contribution can be used to basic network control (e.g., electric appliances, industry control, automatic control systems, remote management, Environmental Monitoring) because it does not require too complicated packet handshake procedure. With our analysis of packet processing rate, we truly proposed a feasible study in some respects.