Current control with AD-conversion-complete-timer

linear_pendulum_2009/avr/current_control.c

@@ -15,11 +15,25 @@
 #include <avr/interrupt.h>
 #include <inttypes.h>
 
-volatile int16_t ref = 20;
+
+// reference generation variables
+volatile int16_t ref = 200;
 volatile int16_t refCount = 0;
 volatile int8_t refFlag = 0;
+
+
+
+// control variables
+volatile unsigned char lbyte,hbyte;  
+volatile int16_t result;
+volatile int16_t ctrl; 
+volatile int16_t ctrl_out;
+volatile int16_t temp;
 volatile uint8_t alt = 1;
 
+volatile uint8_t low, high;
+
+
 
 /* Routine used to set the red LED */
 void setLED(uint8_t on)
@@ -46,7 +60,8 @@ static void putchar(unsigned char ch)
 /* Interrupt service routine for handling incoming bytes on the serial port 
  might be needed to catch incoming bytes */
 SIGNAL(SIG_UART_RECV){}
-/* Read 10-bit input using the AD converter */
+
+
 static inline int16_t readInput() {
   uint8_t low, high;
   ADCSRA |= 0x40;
@@ -55,7 +70,7 @@ static inline int16_t readInput() {
   high = ADCH;
   return ((high<<8) | low) - 512;
 }
-
+	
 
 /* Write 8-bit output using the PWM-generator */
 static inline void writeOutput(int16_t val) {
@@ -68,76 +83,48 @@ static inline void writeOutput(int16_t val) {
     OCR1BH = 0;    //(unsigned char) (val&0xff00);
     OCR1BL = (unsigned char) (val&0x00ff);
   }
-
-  //unsigned char lbyte,hbyte;
-  //hbyte = ((val & 0xff00)>>8);	//Get ADC result high byte
-  //lbyte = ((val & 0x00ff));	//Get ADC result low byte
-
-  //putchar(hbyte);
-  //putchar(lbyte);
 }
 
 
-/* Periodic timer interrupt */
-SIGNAL(SIG_OUTPUT_COMPARE2)
+
+/* Interrupt when AD-conversion completes */
+SIGNAL(SIG_ADC)
 {
-  
+  setPA4(1);
 
-  // PORTA &= 0xef;
-  unsigned char lbyte,hbyte;  
-  int16_t result;
-  int16_t ctrl; 
-  int16_t ctrl_out;
-  int16_t temp;
+  // Read input
+  low = inp(ADCL);
+  high = inp(ADCH);
+  result =  ((high<<8) | low) - 512;
   
-  setPA4(alt);
-
-  result = readInput();
-
-  setPA4(0);  
-
+  // Scale incoming current measurement
   result = result*3; //!!!!!!!!!!!!!!!!!!!!!!!
 
-  // Compensate for offset in measurements
+  // Scale incoming current measurement
   // result += 13;
-
-  //hbyte = (((ref-result) & 0xff00)>>8);	//Get ADC result high byte
-  //lbyte = (((ref-result) & 0x00ff));	        //Get ADC result low byte
-  
-  // Transmit data
-  //putchar(hbyte);	//high byte
-  //putchar(lbyte);	//low byte
-
-  //hbyte = ((result & 0xff00)>>8);	//Get ADC result high byte
-  //lbyte = ((result & 0x00ff));	//Get ADC result low byte
-  
-  // Transmit data
-  //putchar(hbyte);	//high byte
-  //putchar(lbyte);	//low byte
-  
-  // control
+    
+  //control
   ctrl = ref-result;
   ctrl = ((ctrl + (1<< 2)) >> 3);
   
   //saturation/rounding to 8 bit
-  if (ctrl > 127)
-    ctrl_out = 127;
-  else if (ctrl < -128)
-    ctrl_out = -128;
+  if (ctrl > 511)
+    ctrl_out = 511;
+  else if (ctrl < -511)
+    ctrl_out = -511;
   else
     ctrl_out = ctrl;
- 
-  //writeOutput(ctrl_out);
-  writeOutput(ref);
-
-
- 
-  temp = (int16_t) ctrl_out;
-  hbyte = ((temp & 0xff00)>>8);	//Get ADC result high byte
-  lbyte = ((temp & 0x00ff));	//Get ADC result low byte
-  putchar(hbyte); 
-  putchar(lbyte);
- 
+
+
+  // write output
+  if (ctrl_out < 0) {
+    PORTC = 0x80+(PORTC & 0x7F);
+    OCR1BL = (unsigned char) (-ctrl_out);
+  } else {
+    PORTC = (PORTC & 0x7F);
+    OCR1BL = (unsigned char) (ctrl_out);
+  }
+  setPA4(0);
 }
 
 
@@ -186,8 +173,8 @@ int main()
   outp(0x10,DDRA);  // test pin output
 
   /* Timer section */
-  // Enable TCNT2 (timer2) compare match interrupts, and timer0 overflow interrupts
-  outp(BV(OCIE2)|BV(TOIE0),TIMSK);
+  // Enable timer0 overflow interrupts
+  outp(BV(TOIE0),TIMSK);
   
   /* Timer 1, 8 bit fast PWM no prescaling -> h_pwm=17.35 micros */
   outp(BV(COM1A1)|BV(COM1B1)|BV(WGM10),TCCR1A);
@@ -203,10 +190,10 @@ int main()
   
   
   /* Timer 2 (control loop), prescaler 256, clear on compare match (28), -> h = 0.5 ms */
-  outp(BV(WGM21)|BV(CS22)|BV(CS21),TCCR2);
-  outp(28,OCR2);
+  //  outp(BV(WGM21)|BV(CS22)|BV(CS21),TCCR2);
+  //outp(28,OCR2);
   /* Reset timer 2 */
-  outp(0,TCNT2);
+  //outp(0,TCNT2);
 
   /* Timer 0 for reference generation, prescaler = 1024 periodic h = ? */
   outp(BV(CS02)|BV(CS00),TCCR0);
@@ -222,13 +209,8 @@ int main()
   /* AREF (AREF is 5V) pin external capacitor, MUX0 for current, MUX3?? for pendulum angle */
   outp(BV(REFS0)|BV(MUX0),ADMUX); 	
   
-  // Enable ADC interrupts, start first conversion (what do adps0-2 do), prescaler 128
-  // outp(BV(ADEN)|BV(ADSC)|BV(ADPS2)|BV(ADPS1)|BV(ADPS0),ADCSRA);
-  // Enable ADC interrupts, start first conversion (what do adps0-2 do), prescaler 8
-  // outp(BV(ADEN)|BV(ADSC)|BV(ADPS1)|BV(ADPS0),ADCSRA);
-
-  // Enable ADC interrupts, start first conversion (what do adps0-2 do), prescaler 64
-  outp(BV(ADEN)|BV(ADSC)|BV(ADPS2)|BV(ADPS1),ADCSRA);
+  // Enable ADC interrupts, start first conversion (what do adps0-2 do), prescaler 32
+  outp(BV(ADEN)|BV(ADATE)|BV(ADSC)|BV(ADIE)|BV(ADPS2)|BV(ADPS0),ADCSRA);
 
   // outp(BV(ADEN)|BV(ADSC),ADCSRA);