Design Of Intelligent Car And Its Debugging System Based On Freescale MCU

Research and design of this article is based on National Undergraduate Students"Freescale Cup" Intelligent Car Competition.The Research build the intelligent carsystem and its debugging system on the platform of car model stipulated by thecommittee of the competition.This design choose the MC9S12XS128provided byFreescale Semiconductor as the MCU,and choose the CMOS camera OV7620as theimage sensor.The camera collect the image information of the track and transfer it toMCU to analyse different types of the track.Base on the analysis results,we can usePID to control the intelligent car. Bootloader can realize online programmingexpediently and improve the efficiency of development simultaneously.This design of intelligent car system is consist of the mechanical structuremodification of car model,hardware and software of intelligent car and its debuggingsystem. The specific research content is as follows:(1) The mechanical structure modification of car model mainlyincludes:adjustment of front and rear wheel;the PCB layout;modification ofchassis;and installation of image sensor,servo,encoder etc.(2)The design of hardware circuit mainly includes:1)LDO circuit by using LowDropout Regulator which provide stable voltage for MCU and other modules;2)Thecamera module for collecting the image information;3) Omron encoder is used forspeed measurement to realize closed-loop control;4) High Current PN Half Bridgechip BTN7971is used for building a H bridge motor drive circuit;5)Interface circuitsfor other modules.(3)The software design includes:The code of image collection, imagefiltering,PID control of servo and motor.(4) For the Bootloader, upper computer software is designed by Visual C#, whichtransmit the S19file generated by Code Warrior through SCI to MCU. At the sametime, the MCU Bootloader decode the S19file and program it into Flash.