complete

main.c

@@ -6,123 +6,132 @@
 #pragma config FOSC = INTRCIO   // Internal oscillator
 #pragma config WDTE = OFF       // Watchdog timer off
 #pragma config PWRTE = ON       // Power-up timer enabled
+#pragma config MCLRE = OFF
 #define _XTAL_FREQ 4000000
 
+volatile uint8_t current_button_status = 1;
+volatile uint8_t current_mode = 0;
+volatile uint8_t servo_pos = 127; // 0=1ms, 255=2ms
+volatile uint8_t pulse_state = 0; // 0=start pulse, 1=end pulse
+volatile uint8_t isincreasing = 0;
+
+void __interrupt() ISR(void) {
+    INTCONbits.GIE = 0;
+    if (PIR1bits.TMR1IF) {
+        PIR1bits.TMR1IF = 0;    // Clear interrupt flag
+        static uint16_t off_ticks; // Retains value between interrupts
+        static uint16_t timer;
+        if (pulse_state == 0) {
+            // Calculate pulse parameters
+            uint16_t on_ticks = 75 + ((uint16_t)servo_pos * 237) / 255; // Map to 0.5ms-2.5ms
+            off_ticks = 2500 - on_ticks; // 2500 ticks = 20ms            
+            RC5 = 1;            // Start pulse
+            timer = 65535 - on_ticks;
+            TMR1L = (unsigned char)(timer & 0xFF);
+            TMR1H = (unsigned char)(timer >> 8);
+            pulse_state = 1;
+        } else {
+            RC5 = 0;            // End pulse
+            timer = 65535 - off_ticks;
+            TMR1L = (unsigned char)(timer & 0xFF);
+            TMR1H = (unsigned char)(timer >> 8);
+            pulse_state = 0;
+        }
+    }
+    INTCONbits.GIE = 1;
+}
+
 void setup() {
-    // Set RA0 as analog input, rest of PORTA as outputs
-    TRISA = 0x01;
     
-    // Set PORTC as outputs except RC5 which will toggle PWM
+    // Set RA1 as digital input
+    ANSEL = 0;
+    CMCON = 0x07;
     TRISC = 0x00; 
+    TRISAbits.TRISA1 = 1;    
+    WPUAbits.WPUA1 = 1;        
+    OPTION_REGbits.nRAPU = 0;
     
-    // Enable analog input on RA0
+    // Configure Timer1
-    ANSEL = 0x01;
+    T1CON = 0b00110000; // Timer1: prescaler 1:8, internal clock, OFF
+    TMR1H = (65536 - 188) >> 8; // Initial 1.5ms pulse (high byte)
+    TMR1L = (65536 - 188) & 0xFF; // Initial 1.5ms pulse (low byte)
+    PIR1bits.TMR1IF = 0; // Clear interrupt flag
+    PIE1bits.TMR1IE = 1; // Enable Timer1 interrupt
+    INTCONbits.PEIE = 1; // Enable peripheral interrupts
+    INTCONbits.GIE = 1;  // Enable global interrupts
+    T1CONbits.TMR1ON = 1;
     
     // Configure ADC
-    ADCON0 = 0b00000101;   // Channel 0, ADC enabled
+    TRISAbits.TRISA2 = 0;    
-    ADCON1 = 0b10001110;   // Right justified, Vdd/Vss reference
+    ANSELbits.ANS2 = 1;
-    
+    ADCON0 = 0b00001001;
-    // Timer0 initialization
+    ADCON1 = 0;   
-    OPTION_REG = 0b11110111;  // Prescale = 256, Internal clock source
-    TMR0 = 0;                 // Clear timer register
-}
-
-#define SERVO_MIN_PULSE_US 750  // Minimum pulse width (approximately 0°)
-#define SERVO_MAX_PULSE_US 2250 // Maximum pulse width (approximately 180°)
-void delay_us(uint16_t us) {
-    uint16_t i;
-    for(i = 0; i < us; i++) {
-        _nop();  // Insert assembly-level no-operation instruction
-    }
-}
-
-void generate_pwm(uint16_t pulse_width_us) {
-    RC5 = 1;                     // Start high
-    delay_us(pulse_width_us);  // Keep high for desired pulse width
-    RC5 = 0;                     // Go low until next pulse
-    delay_us(20 - (pulse_width_us / 1000));  // Wait remaining 20ms period
 }
 
 #define bool uint8_t
 #define false 0
 #define true 1
-volatile bool button_pressed = false;
+
-uint8_t current_mode = 0;
+void UpdateLeds()
+{
+    RC0 = current_mode == 0;
+    RC1 = current_mode == 1;
+    RC2 = current_mode == 2;
+}
 
 void check_button() {
-    if (!RA1 && !button_pressed) {  // Detect falling edge of button press
+    if (!RA1 && current_button_status) {
-        button_pressed = true;
+        __delay_ms(20);             
-        __delay_ms(50);             // Basic debounce delay
+        if(!RA1) {            
-        current_mode++;
+            current_mode = (current_mode + 1) % 3; // Cycle through modes        
-        if (current_mode > 2) current_mode = 0;  // Cycle through modes
+            UpdateLeds();        
-        
-        // Update LEDs based on mode
-        switch(current_mode) {
-            case 0:
-                RC0 = 1; RC1 = 0; RC2 = 0; break;  // Manual mode LED
-            case 1:
-                RC0 = 0; RC1 = 1; RC2 = 0; break;  // Center mode LED
-            case 2:
-                RC0 = 0; RC1 = 0; RC2 = 1; break;  // Oscillator mode LED
         }
     }
-    if (RA1) {
+    current_button_status = RA1;
-        button_pressed = false;  // Release button
+}
+
+void smooth_servo(uint8_t target_pos) {
+    // Move servo_pos towards target_pos gradually
+    if (servo_pos < target_pos) {
+        servo_pos++;
+    } else if (servo_pos > target_pos) {
+        servo_pos--;
     }
 }
 
-void manual_mode() {
+inline uint8_t read_adc() {
-    uint16_t adc_value = (ADRESH << 8) | ADRESL;  // Get ADC value
+    ADCON0bits.GO = 1;
-    uint16_t pulse_width = (SERVO_MIN_PULSE_US + (adc_value * (SERVO_MAX_PULSE_US - SERVO_MIN_PULSE_US) / 1023));
+    while(ADCON0bits.GO_DONE); 
-    generate_pwm(pulse_width);
+    return ADRESH;
-}
-
-void center_mode() {
-    generate_pwm((SERVO_MIN_PULSE_US + SERVO_MAX_PULSE_US) / 2);
-}
-
-int8_t direction = 1;  // Direction of movement
-uint8_t osc_duty = 75; // Start at min duty cycle
-
-uint16_t osc_pulse_width = SERVO_MIN_PULSE_US;
-bool increasing = true;
-
-void oscillator_mode() {
-    generate_pwm(osc_pulse_width);
-    
-    if (increasing) {
-        osc_pulse_width += 10;  // Gradual increment
-        if (osc_pulse_width >= SERVO_MAX_PULSE_US) {
-            increasing = false;
-        }
-    } else {
-        osc_pulse_width -= 10;  // Gradual decrement
-        if (osc_pulse_width <= SERVO_MIN_PULSE_US) {
-            increasing = true;
-        }
-    }
 }
 
 void main() {
     setup();  // Initialize peripherals
-    
+    UpdateLeds();    
     while(1) {
         check_button();  // Check for button presses              
-        
         switch(current_mode) {
             case 0:                
-                manual_mode();
+                smooth_servo(read_adc());
+                __delay_us(100);
                 break;
             case 1:
-                center_mode();
+                //target_pos = 511;
+                smooth_servo(127);
+                __delay_us(100);
                 break;
             case 2:
-                oscillator_mode();
+                if(isincreasing) {                                            
+                    smooth_servo(servo_pos + 1);
+                     __delay_ms(10);
+                    if(servo_pos + 1 >= 254) isincreasing = 0;
+                } else
+                {
+                    smooth_servo(servo_pos - 1);
+                     __delay_ms(10);
+                    if(servo_pos - 1  <= 0) isincreasing = 1;
+                }
                 break;
         }
-        
-        // Perform ADC conversion
-        GO_nDONE = 1;  // Start ADC conversion
-        while(GO_nDONE);  // Wait for completion
     }
 }