The Design And Verification Of The SPI Interface In WIFI Chip

With the vigorous development of Internet of Things,wireless communication technology due to the convenient advantage in networking,so that it can be widely used in many fields of the Internet of things.WIFI technology has been widely used as the mainstream of wireless communication technology,with its faster transmission speed and stronger network stability.WIFI chip as WIFI hardware implementation,its application will be more and more widely in the future,so the design of WIFI chips and peripheral equipment of communication has the practical significance.Serial interface is added in the WIFI chip design,chip with serial peripheral data transmission can be realized.SPI is more and more widely used because of its simple circuit structure,reliable communication,and serial transmission speed,especially for data transmission between processors and serial peripherals.Therefore,this paper study the design of SPI interface in WIFI chip,using the widely used AMBA 2.0 bus,so that the design of the SPI interface module can be more widely used in different systems.In this paper,the top-down design method is adopted.Firstly,based on the So C architecture of WIFI chip,the design requirements of SPI interface in the chip are analyzed,and the top module is planned and the interface signal is designed and optimized.The SPI module is divided into sub-modules such as AHB interface module,signal synchronization module,clock divider module,data cache module,transmission mode detection module,master / slave state machine module,interrupt logic module and DMA interface module.Secondly,on the basis of the complete module RTL design,set up the simulation test platform,through module simulation and system simulation,carries on the preliminary verification for design work.On the basis of functional simulation,select the XILINX Company ZC706-ZYNQ development board,build FPGA verification platform.The use of Vivado software to the layout of the integrated layout and distribution of bit stream file,the use of SDK tools to download the file to the FPGA development board,Co-verification based on hard and soft;Finally,take SMIC55 nm process for tape-out,and test the chip,the application is burned to Flash,through the SPI program will be transmitted to the WIFI chip internal implementation,observe the operation of the program results,the indirect test SPI interface function.By way of capturing clock and data lines cross oscilloscope,Visual inspection frequency and different protocols.The experimental results of the SPI interface designed in this paper show that the SPI interface can meet the design performance: compatible with three kinds of serial data transmission protocols,supports full-duplex and half-duplex communication,configurable master-slave mode,support direct memory access,configurable data transmission length,support single-speed,two-speed and four-speed data transmission,support different data transmission mode to communicate with a variety of Flash,single-line data rate up to 40 Mbps,well-function,wide applicability and in line with design requirements.