发布时间 : 星期日 文章停车场管理系统设计与实现-外文翻译更新完毕开始阅读d54c0231cec789eb172ded630b1c59eef8c79a39
are used to adjust backlight.Control and data lines of LCD assigned to FPGA are shown in figure 3.
Figure 3(a):LCD interfacing with FPGA(Pin assignment)
Stepper motor interfaced with FPGA by using ULN 2003. Any I/O port of Development Boardcan be used for interfacing. Here, D I/O port of Development Board is used for interfacing withstepper motor. Pin assignment of FPGA, ULN 2003, and stepper motor is shown in figure 3(b).
Figure 3(b):stepper motor interfacing with FPGA(Pin assignment)
RF Module: In this module IR trans-receiver pair is used to detect vehicle presence. IR sensors transmit slot’s status to HT12E encoder. Encoder consists of 18 pin configuration. Parallel data convert into serial by encoder. Data is collected at data
out pin of encoder. From data out pin data serially transmit towards RF transmitter. Data serially received at RF receiver. HT12D decoder receiver’s data from RF receiver, then converter back serial to parallel form. HT12D decoder’s data pins are interfaced with Virtex 5 C I/O port signal pins.
Figure 3(c):HT12D Decoder interfacing with FPGA(Pin assignment) Platform: consisting of IR sensors, HT12E encoder, RF module, HT12D decoder and LEDs of FPGA are used to display results. Software Module: Xilinx version 12.4 is used for VHDL coding. Interfacing: In proposed system LCD, Stepper motor and RF models interfacing is done with FPGA.
3.2 Finite state machine for the operation of the system
In order to implement parking system a state diagram is constructed. As we know that the proposed system performs space availability, motor rotation for door opening, identification and slot availability information. The system includes:
Identification Slot Selection
4. FPGA IMPLEMENTATION
4.1 Designing of parking system with State Machine Diagram
ASMD chart is Algorithm State Machine Diagram. This shows the working of parking system in the form of a flow chart. For the proposed model, oval shaped boxes are used to describe the output that depends upon past state as well as present input. The ASMD chart shown in figure 4 gives working of the car parking system. At
the entrance of parking area, LCD displays the status of parking system. If space is available then LCD displays space available else LCD displays no space exit. According to space status motor rotates in clockwise direction. After that identification unit identifies the person. For new member temporary card is allotted. After identification, slot status is checked. Status can be filled, empty or reserved. RF sensors are used in this process.
Figure 4:ASMD char for parking system
4.2 Results
After space checking door will open with the help of stepper motor. Here in simulation clk pulse and reset is applied as an input. Cnt and clkd are signals. When reset goes high-to-low, stepper motor rotates. Simulation wave forms of stepper motor are shown in figure 4(a)
Figure 4（a）:Simulation of stepper motor ratation
Figure 4(b) :RTL view of stepper motor and LCD interfacing Figure 4(b):RTL view of stepper motor and LCD interfacing
Figure above shows the RTL view of stepper motor and LCD interfacing. clk is system clock signal. rst is control signal. D(7:0) are data lines. Z(3:0) is output signal of stepper motor. E is enable signal of LCD. rs is register select signal. rw is read/write controlsignal.
When door opened, identification process starts. w, w1, w2, z, clk and reset are inputs. Out_1 is output. Current_state and next_state describes visitor is identified or a new member has come. Pr_st and nx_st shows person which is identified. Following simulation shows identification process: