2,10 → 2,12 |
#include <avr/interrupt.h> |
#include "fc.h" |
#include "eeprom.h" |
#include "uart.h" |
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volatile int16_t ServoValue = 0; |
volatile uint16_t ServoValue = 0; |
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/*****************************************************/ |
/* Initialize Timer 2 */ |
/*****************************************************/ |
20,33 → 22,33 |
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// set PD7 as output of the PWM for nick servo |
DDRD |=(1<<DDD7); |
PORTD |= (1<<PORTD7); |
PORTD &= ~(1<<PORTD7); // set PD7 to low |
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// Timer/Counter 2 Control Register A |
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// Waveform Generation Mode is Fast PWM (Bits: WGM22 = 0, WGM21 = 1, WGM20 = 1) |
// PD7: Clear OC2B on Compare Match, set OC2B at BOTTOM, non inverting PWM (Bits: COM2A1 = 1, COM2A0 = 0) |
// PD7: Normal port operation, OC2A disconnected, (Bits: COM2A1 = 0, COM2A0 = 0) |
// PD6: Normal port operation, OC2B disconnected, (Bits: COM2B1 = 0, COM2B0 = 0) |
TCCR2A &= ~((1<<COM2B1)|(1<<COM2B0)|(1<<COM2A0)); |
TCCR2A |= (1<<COM2A1)|(1<<WGM21)|(1<<WGM20); |
TCCR2A &= ~((1<<COM2A1)|(1<<COM2A0)|(1<<COM2B1)|(1<<COM2B0)); |
TCCR2A |= (1<<WGM21)|(1<<WGM20); |
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// Timer/Counter 2 Control Register B |
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// Set clock divider for timer 2 to SYSKLOCK/256 = 20MHz / 256 = 78.128 kHz |
// The timer increments from 0x00 to 0xFF with an update rate of 78.128 kHz or 12.8 us |
// hence the timer overflow interrupt frequency is 78.128 kHz / 256 = 305.176 Hz or 3.276 ms |
// Set clock divider for timer 2 to SYSKLOCK/64 = 20MHz / 64 = 312.5 kHz |
// The timer increments from 0x00 to 0xFF with an update rate of 312.5 kHz or 3.2 us |
// hence the timer overflow interrupt frequency is 312.5 kHz / 256 = 1220.7 Hz or 0.8192 ms |
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// divider 256 (Bits: CS022 = 1, CS21 = 1, CS20 = 0) |
TCCR2B &= ~((1<<FOC2A)|(1<<FOC2B)|(1<<CS20)|(1<<WGM22)); |
TCCR2B |= (1<<CS22)|(1<<CS21); |
// divider 64 (Bits: CS022 = 1, CS21 = 0, CS20 = 0) |
TCCR2B &= ~((1<<FOC2A)|(1<<FOC2B)|(1<<CS21)|(1<<CS20)|(1<<WGM22)); |
TCCR2B |= (1<<CS22); |
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// Initialize the Output Compare Register A used for PWM generation on port PD7. |
OCR2A = 10; //10 * 12.8us = 1.28 ms high time |
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// Initialize the Timer/Counter 2 Register |
TCNT2 = 0; |
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// Initialize the Output Compare Register A used for PWM generation on port PD7. |
OCR2A = 10; |
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// Timer/Counter 2 Interrupt Mask Register |
// Enable timer output compare match A Interrupt only |
TIMSK2 &= ~((1<<OCIE2B)|(1<<TOIE2)); |
59,46 → 61,92 |
/*****************************************************/ |
/* Control Servo Position */ |
/*****************************************************/ |
ISR(TIMER2_COMPA_vect) // every OCR2A * 12.8 us (compare match) |
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ISR(TIMER2_COMPA_vect) // every 256 * 3.2 us = 0.819 us ( on compare match of TCNT2 and OC2A) |
{ |
static uint8_t timer = 10; |
static uint8_t PostPulse = 0x80; // value for last pwm cycle in non inverting mode (clear pin on compare match) |
static uint16_t FilterServo = 100; // initial value, after some iterations it becomes the average value of 2 * FCParam.ServoNickControl |
static uint16_t ServoState = 40; // cycle down counter for this ISR |
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if(!timer--) |
{ |
// enable PWM on PD7 in non inverting mode |
TCCR2A &= ~(0<<COM2A0); |
TCCR2A |= (1<<COM2A1); |
#define MULTIPLIER 4 |
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ServoValue = FCParam.ServoNickControl; |
// inverting movment of servo |
if(ParamSet.ServoNickCompInvert & 0x01) |
{ |
ServoValue += ((int32_t) ParamSet.ServoNickComp * (IntegralNick / 128)) / 512; |
} |
else // non inverting movement of servo |
{ |
ServoValue -= ((int32_t) ParamSet.ServoNickComp * (IntegralNick / 128)) / 512; |
} |
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// limit servo value to its parameter range definition |
if(ServoValue < ParamSet.ServoNickMin) |
{ |
ServoValue = ParamSet.ServoNickMin; |
} |
else if(ServoValue > ParamSet.ServoNickMax) |
{ |
ServoValue = ParamSet.ServoNickMax; |
} |
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// update PWM |
OCR2A = ServoValue; |
timer = ParamSet.ServoNickRefresh; |
} |
else |
{ |
// disable PWM at PD7 |
TCCR2A &= ~((1<<COM2A1)|(1<<COM2A0)); |
// set PD7 to low |
PORTD &= ~(1<<PORTD7); |
} |
switch(ServoState) |
{ |
case 4: |
// recalculate new ServoValue |
ServoValue = 0x0030; // Offset (part 1) |
FilterServo = (3 * FilterServo + (uint16_t)FCParam.ServoNickControl * 2) / 4; // lowpass static offset |
ServoValue += FilterServo; // add filtered static offset |
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if(ParamSet.ServoNickCompInvert & 0x01) |
{ // inverting movement of servo |
ServoValue += ((int32_t) ((int32_t)ParamSet.ServoNickComp * IntegralNick) / 128L )/ (512L/MULTIPLIER); |
} |
else |
{ // non inverting movement of servo |
ServoValue -= ((int32_t) ((int32_t)ParamSet.ServoNickComp * IntegralNick) / 128L) / (512L/MULTIPLIER); |
} |
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// limit servo value to its parameter range definition |
if(ServoValue < ((uint16_t)ParamSet.ServoNickMin * 3) ) |
{ |
ServoValue = (uint16_t)ParamSet.ServoNickMin * 3; |
} |
else |
if(ServoValue > ((uint16_t)ParamSet.ServoNickMax * 3) ) |
{ |
ServoValue = (uint16_t)ParamSet.ServoNickMax * 3; |
} |
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DebugOut.Analog[20] = ServoValue; |
// determine prepulse width (remaining part of ServoValue/Timer Cycle) |
if ((ServoValue % 255) < 45) |
{ // if prepulse width is to short the execution time of thios isr is longer than the next compare match |
// so balance with postpulse width |
ServoValue += 77; |
PostPulse = 0x60 - 77; |
} |
else |
{ |
PostPulse = 0x60; |
} |
// set output compare register to 255 - prepulse width |
OCR2A = 255 - (ServoValue % 256); |
// connect OC2A in inverting mode (Clear pin on overflow, Set pin on compare match) |
TCCR2A=(1<<COM2A1)|(1<<COM2A0)|(1<<WGM21)|(1<<WGM20); |
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break; |
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case 3: |
case 2: |
case 1: |
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if(ServoValue > 255) // is larger than a full timer 2 cycle |
{ |
PORTD |= (1<<PORTD7); // set PD7 to high |
TCCR2A = (1<<WGM21)|(1<<WGM20); // disconnect OC2A |
ServoValue -= 255; // substract full timer cycle |
} |
else // the post pule must be generated |
{ |
TCCR2A=(1<<COM2A1)|(0<<COM2A0)|(1<<WGM21)|(1<<WGM20); // connect OC2A in non inverting mode |
OCR2A = PostPulse; // Offset Part2 |
ServoState = 1; // jump to ServoState 0 with next ISR call |
} |
break; |
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case 0: |
ServoState = (uint16_t) ParamSet.ServoNickRefresh * MULTIPLIER; // reload ServoState |
PORTD &= ~(1<<PORTD7); // set PD7 to low |
TCCR2A = (1<<WGM21)|(1<<WGM20); // disconnect OC2A |
break; |
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default: |
// do nothing |
break; |
} |
ServoState--; |
} |
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