| The subject take the study of semi-conductor device characteristic instrument as background, research real-time control system based on PCI bus in instrument , realize measuring controller in FPGA device finally.In order to guarantee the real-time performance of the controller ,we use hardware circuit to implement entire the control funtion. Even though hardware control is more complex than software control from the angle of implementation, but a series characteristic about hardware controller, including high speed , collateral signal flow and control signal output based on clock edge, may fundamentally guarantee the real-time performance of control system.PCI bus is selected as media of information alternation between measuring controller maked of hardware and host computer. For the sake of translation mutually between PCI bus operation and local bus operation, we need research and realize PCI bus interface on the basis of commanding PCI bus specification. In research subject, PCI9054 interface chip is used by way of implementing this funtion. Emphases of study include time sequence of local bus signal, local bus interface, register configuration, interrupt handling mechanism and DMA operational mode. Practice show that computer can acquire real-time data storing in FIFO through starting DMA transmission in the process of interrupt service routine on the basis of high-powered PCI bus.Design of logical circuit of measuring controller is the key problem of the topic research. On the basis of analysing measuring theory,we should conclude functional requirement for control circuit, define the control signal, work out overall control scheme, design each control module. Measuring controller is described by Hardware Description Language(HDL), configured and realized in FPGA device. Author of this paper discuss design idea and theory of some pivotal control module.FPGA device including control logical circuit and PCI9054 interface chip is assembled on the circuit board ultimately. The specification of wire layout is main research topic in the process of producing circuit board. In addition, author develop driver of circuit board to make sure that application program can access mearsuring controller.Real-time control system of instrument in theme achieve preferable application effect on the semi-conductor device characteristic instrument, also, control circuit can run stably. Through observing actual working process of control circuit by logic analyzer,we can affirm that time sequence of output control signal accord with design requirement, control circuit can also acquire measuring data cooperate with measuring process and transmit real-time data to storage in the computer by interrupt. In conclusion, in the field of study and manufacture of semi-conductor device characteristic instrument, the subject apply a series of original technology such as PCI bus , FPGA design and coordinate design of multiple state machine, design control system armed with favourable real-time performance , moreover, establish solid foundation for meeting every design target of instrument. |
