Sensor Integration and Servo Control with PIC18F4321
This C program, designed for the PIC18F4321 microcontroller, showcases a practical implementation of ultrasonic sensor integration and servo control for distance measurement. The code not only initializes hardware settings but also employs timer-based operations for precise sensor functionality. By incorporating conditional servo controls based on distance thresholds, the program demonstrates its adaptability in various applications such as robotics or automation. The LCD display enhances user interaction by presenting the calculated distance. Whether you're exploring microcontroller programming or need help with your C assignment, this code provides a comprehensive example of utilizing sensors and actuators in embedded systems, offering insights into real-world applications and the fundamentals of programming for such scenarios.
Block 1: Header Files and Definitions
#include
#include
#include
#include
#include
#include
#include
This block includes necessary header files for the PIC18F4321 microcontroller, standard input/output operations, timers, LCD, and delays. The inclusion of these files indicates that the program involves timer-based operations, LCD interfacing, and possibly some standard I/O functions.
#define TRIG LATAbits.LATA1
#define ECHO PORTAbits.RA2
#define SERVO PORTAbits.RA0
These lines define symbolic names for the TRIG, ECHO, and SERVO pins. This is useful for better code readability and maintenance.
#pragma config WDT = OFF
#pragma config LVP = OFF
#pragma config BOR = OFF
#pragma config OSC = INTIO2
These are configuration directives for the microcontroller. They set options related to the watchdog timer, low-voltage programming, brown-out reset, and oscillator selection.
unsigned int TimeoutCounter = 0;
short int DH;
long int pulse_count;
char LCD_Char[16];
float pulse_time;
float distance;
int distance_w, distance_d;
Variable declarations for various purposes, including counters, pulse timing, distance calculation, and LCD display. Some of these variables are used for intermediate calculations, while others store the final results.
Block 2: Main Function Setup
void main(void)
{
ADCON1=0x0F;
TRISAbits.TRISA0 = 0;
TRISAbits.TRISA1 = 0;
TRISAbits.TRISA2 = 1;
TRISCbits.TRISC0 = 1;
TRISCbits.TRISC4 = 0;
LATCbits.LATC4 = 1;
T0CON=0x08;
TRIG = 0;
INTCONbits.T0IE = 1;
INTCONbits.T0IF = 0;
TRISD = 0;
LCDInit();
LCDClear();
CursorHome();
CursorMode();
DispControl();
while (1)
{
// ...
}
}
This block initializes various hardware configurations and sets up the main loop. It configures the analog-to-digital converter, sets pin directions, initializes the timer, and configures the LCD. The while loop indicates the main program loop.
Block 3: Ultrasonic Sensor and Timer Operations
WriteTimer0(0);
TRIG = 1;
Delay1TCY();
Delay1TCY();
TRIG = 0;
TimeoutCounter=0;
while((ECHO==0)&&(TimeoutCounter<1000))
TimeoutCounter++;
T0CONbits.TMR0ON=1;
while((ECHO==1)&&!(INTCONbits.T0IF));
T0CONbits.TMR0ON=0;
INTCONbits.T0IF=0;
ReadTimer0();
DH=TMR0H;
pulse_count=(TMR0L|(DH<<8));
pulse_time=pulse_count/1000000.0*4;
distance=pulse_time*340000/2.0;
distance_w=(distance);
distance_d=((distance*10)-distance_w*10);
This block sends a pulse using the TRIG pin, measures the time it takes for the pulse to return (ECHO), and calculates the distance. It utilizes Timer 0 to measure the pulse duration.
Block 4: Servo Control Based on Distance
if (distance_w>=50)
{
// Move the servo to the mid position
// ... (servo control logic)
}
if (distance_w<50)
{
// Move to the leftmost position
// ... (servo control logic)
// Stop for 2 seconds
// ... (delay logic)
// Move to the rightmost position
// ... (servo control logic)
// Stop for 2 seconds
// ... (delay logic)
// Move the servo to the mid position
// ... (servo control logic)
}
sprintf(LCD_Char, "Dis: %d.%d mm",distance_w,distance_d);
LCDClear();
DStrToLCD(LCD_Char);
Delay10KTCYx(50);
This block controls the servo motor based on the calculated distance. It includes logic for moving the servo to different positions and introduces delays to control the timing of movements. The measured distance is also displayed on the LCD.
Block 5: Infinite Loop
while (1)
{
// ... (more logic can be added here)
}
This infinite loop is a placeholder for additional program logic that can be added in the future. As it stands, the main functionality of the program is contained in the previous blocks.
Conclusion
In conclusion, this microcontroller programming example showcases the fusion of hardware and software expertise, offering a glimpse into advanced applications of PIC18F4321. Whether you're delving into the intricacies of timer operations, servo motor control, or LCD interfacing, our experts at ProgrammingHomeworkHelp.com are ready to guide you. With a commitment to clarity and precision, we unravel the complexities of programming tasks, ensuring you gain a profound understanding. Your journey in mastering microcontroller programming begins here. Trust our seasoned professionals to provide the support and insights needed to navigate the challenges and excel in your endeavors.