'--------Title-------- ' File......sonar_car_a.pbp ' Started....2/22/10 ' Microcontroller used: Microchip Technology 16F88 ' microchip.com ' PBPro Code, micro-Engineering Labs, Inc. ' melabs.com '--------Program Desciption-------- ' First in a series of 4 programs that takes the class ' through the development of the final program sonar_car1.pbp. ' This first program positions the servo in the starting ' position then pans the servo through 6 steps. '-------------Comments------------- ' MAKE SURE that the servo power source is separate from the ' power source for the PIC16F88 microcontroller. ' Also, MAKE SURE the PULSOUT pin to drive the servo is set ' LOW to establish the correct polarity of the servo pulse. ' To activate RA6 and RA7 as digital I/O pins: ' * Push Compile and Program button ' * The meProg dialog box appears ' * Press the C command button ' * The meProg - Configuration dialog box appears ' * On the Oscillator row, press the drop-down list box ' * Highlight the INTRC option ' * Now program the chip '-----New PicBasic Pro Commands---- ' SELECT CASE ' See around page 129 at: http://www.melabs.com/downloads/pbpm304.pdf '----------PIC Connections--------- ' 16F88 Pin Wiring ' --------- ---------- ' RA0 LCD pin 11(DB4) ' RA1 LCD pin 12(DB5) ' RA2 LCD pin 13(DB6) ' RA3 LCD pin 14(DB7) ' RA4 LCD Register Select(RS) ' RA6 Left Bumper Switch ' RA7 Right Bummper Switch ' RB0 PWM Motor 2 Input into SN755410 ' RB1 Direction Motor 2 Input into SN754410 ' RB2 PWM Motor 1 Input into SN755410 ' RB3 Direction Motor 1 Input into SN754410 ' RB4 Emitter Pin on Sharp SRF04 Ultrasonic ' Range Finder ' RB5 Echo Pin on Sharp SRF04 Ultrasonic ' Range Finder ' RB6 Control Pin to Hobby Servo ' RB7 LCD Enable(E) ' Vdd +5 V ' Vss Ground ' MCLR 4.7K Resistor to +5 V '---------LCD Connections--------- ' LCD Pin Wiring ' --------- ---------- ' 1 Ground(Vss) ' 2 + 5v(Vdd) ' 3 Center of 20K Pot(Contrast) ' 4 RA4(Register Select,RS) ' 5 Ground(Read/Write,R/W) ' 6 RB7(Enable) ' 7 No Connection(DB0) ' 8 No Connection(DB1) ' 9 No Connection(DB2) ' 10 No Connection(DB3) ' 11 RA0(DB4) ' 12 RA1(DB5) ' 13 RA2(DB6) ' 14 RA3(DB7) '--------------Defines------------- ' To make room at PIC16F88 pin RB3 for the Direction Motor 1 ' operation, the LCD enable function (default at RB3) ' must be moved to RB7. The following DEFINES activate the move. define LCD_EREG PORTB ' Set LCD Enable PORT to PORTB define LCD_EBIT 7 ' Set LCD Enable pin to RB7 '--------------Constants----------- conv_to_in con 15 ' Conversion factor to convert ' sonar readings to inches left_time con 2100 ' Set maximum left turn time ' Adjust these time settings ' to correspond to the maximum ' angle position of the ultrasonic ' range finder right_time con 2100 ' Set maximum right turn time '--------Switch Input Pins--------- left_switch var PORTA.6 ' Labels PORTA.6 as left_switch right_switch var PORTA.7 ' Labels PORTA.7 as right_switch '--SN754410 H-Bridge Control Pins-- pwm_motor2 var PORTB.0 ' Labels PORTB.0 as pwm_motor2 dx_motor2 var PORTB.1 ' Labels PORTB.1 as dx_motor2 pwm_motor1 var PORTB.2 ' Labels PORTB.2 as pwm_motor1 dx_motor1 var PORTB.3 ' Labels PORTB.3 as dx_motor1 '-------Sonar Control Pins--------- emit_pin var PORTB.4 ' Labels PORTB.4 as emit_pin echo_pin var PORTB.5 ' Labels PORTB.5 as echo_pin '-------Servo Control Pin---------- servo_pin var PORTB.6 ' Labels PORTB.6 as servo_pin '------------Variables------------- p0 VAR bYTE ' BYTE to store servo pulse period c0 var word ' WORD for counter num var byte ' BYTE for array numbers position var byte[7] ' BYTE for angle array position_max var byte ' BYTE for angle of maximum reading dx var word ' WORD for sonar input dx_in var word[7] ' WORD for distance converted to ' inches array dx_in_max var word ' WORD for maximum distance reading '----------Initialization---------- ANSEL = 0 ' Configure all ADC pins to digital ' operation since not using ADC ' (Analog to Digital Converter) OSCCON = $60 ' Sets the internal oscillator in the ' 16F88 to 4 MHz '-------PORT Configurations-------- PORTA = %00000000 ' Set all PORTA pins to LOW PORTB = %00000000 ' MAKE SURE THE PULSOUT PIN TO THE SERVO ' IS SET LOW TO ESTABLISH THE PROPER ' POLARITY OF THE SERVO PULSE. The PULSOUT ' pin in this program is PORTB.6,(RB6). TRISA = %11000000 ' Set switch pins,(RA6 & RA7), as inputs TRISB = %00100000 ' Set echo input pin,(RB5), as an input '-------------Main Code------------ start: num = 0 ' Set num to 0 dx_in_max = 0 ' Set dx_in_max to 0 ' Move servo to starting position: for c0 = 1 to 20 ' Send out PULSOUT command 20 times PulsOut servo_pin,70 ' Send servo pulse signal to servo_pin ' (PORTB.6) for 0.7 ms. Pulse out time ' The period,(70) is multiplied by the ' increment for a 4 MHz oscillator ' (10 usec) to get a pulse out time ' of 700 us or 0.7 ms. Pause 20 ' Pause 20 msec next c0 ' Pan servo across front of car: For p0 = 70 TO 208 STEP 23 ' Rotate servo counter-clockwise ' through 7 positions, 1 starting ' position (p0 = 70) + 6 steps of 23. for c0 = 1 to 15 ' Send out PULSOUT command 15 times PulsOut servo_pin,p0 ' Send servo pulse signal to servo_pin ' (PORTB.6). Pulse out time varies from ' 0.7 msec to 2.08 ms. Pause 20 ' Pause 20 msec next c0 GoTo start ' Jump to start label end