The Study And Realization Of Protocol Converter Between CAN Bus And SPI Bus

With the degree of industrial modernization is more and more high, fieldbus technology in the industrial control area will play an increasingly important role. there are many different international bus standards, these different standard buses in the future one period of time could not be unified. In order to make industrial control network more flexible, and sometimes require a variety of the same network bus, bus protocol converter between two different bus protocol will become a key technology in the field of industrial control.The paper first compare fieldbus model with OSI model, then described the basic principles of protocol conversion and implementation of protocol converter. This paper analyzes the whole structure protocol converters, adopt the embedded gateway means to realize the protocol converter between CAN bus and SPI bus. the protocol converter is realized from CAN model,SPI model and data storage three aspects. CAN module uses the mode of polling to finish data receive and send; data is storage in a ring buffer structure, use of the DMA data transfer mode to read the data in the buffer or write the data to the buffer; because SPI is a physical layer protocol bus, so design a protocol for PC and protocol converter to communicate, SPI model uses the interrupt mode to finish the communication protocol.Finally, the paper uses LPC11C14 microprocessor create test platform, simulation protocol converters application environment, test protocol converter's data communication correctness and data receiving rate. Based on the analysis of the test data, this paper proved the design protocol converter realized the CAN bus to SPI bus protocol conversion, meet every second can receive 1000 frames of performance indicators.