The Design And Implementation Of GPIB-RS232Controller

Generally, most of domestic instrument are equipped with RS232interface,whichmakes a solo instrument be connected to the computer and does no good to theextension among the various devices via GPIB bus.As for the phenomenon, thecommon method is to transfer the GPIB protocol by hardware addition or softwareaid based on the available devices.In views of these,this paper put forward a schemeto design and implement the GPIB-RS232controller by taking advantage ofProgrammable special interface chip and software program.Firstly, as for the hardware part, the paper analyzed and designed the three mainmodules, the microcontroller and its peripheral circuit, the RS232and the GPIB.Onone hand, it’s required that the pin connections and electrical specification of thetarget board should be reliable so that the STM32minimum system can work well.Onthe other hand, we also lay emphasis on the pin connections of data lines, interruptlines and DMA lines to make it convenient to the software design.Secondly, with regard to the software one, it divides into three parts as well,namely the RS232communication, GPIB interface communication and the SCPIparse.①In terms of the GPIB interface communication, After initializing theNAT9914,we take an innovation of the traditional method—Query method and raisethe Interrupt method to fulfill the six kinds of interface functions such as theT/SH,L/AH,SR and PP in order to finish the basic send and receive operation,servicerequest and response.②As for the SCPI parse part, initially,we build a command binary tree of theSCPI according to the GPIB protocol and corresponding device function,and storageit with the linked structure.Then, we traverse the tree from top to bottom in order toparse the received SPC messages.Thirdly,with the support of hardware and software illustrated above, we build atested system to verify the interface panel performance with two methods:①constructing a test-platform with C language in Microsoft VS2010by calling theVISA library functions to check whether the pre-set interface function can operate well.②with the aid of Agilent USB-GPIB adapter, it put corresponding commandson the Agilent IO interface to send to the programming device and control itsoperation and configure the parameters, as a return, we will receive relevant data orstatus message.Finally, both of the tests showed that the designed GPIB-RS232Controllerperforms well in the system and satisfied the factual application requirements.