| 0,0 → 1,152 |
|---|
| #include <avr/io.h> |
| #include <avr/interrupt.h> |
| #include "fc.h" |
| #include "eeprom.h" |
| #include "uart.h" |
| |
| volatile uint16_t ServoValue = 0; |
| |
| |
| |
| /*****************************************************/ |
| /* Initialize Timer 2 */ |
| /*****************************************************/ |
| // The timer 2 is used to generate the PWM at PD7 (J7) |
| // to control a camera servo for nick compensation. |
| void TIMER2_Init(void) |
| { |
| uint8_t sreg = SREG; |
| |
| // disable all interrupts before reconfiguration |
| cli(); |
| |
| // set PD7 as output of the PWM for nick servo |
| DDRD |=(1<<DDD7); |
| PORTD &= ~(1<<PORTD7); // set PD7 to low |
| |
| |
| // Timer/Counter 2 Control Register A |
| |
| // Waveform Generation Mode is Fast PWM (Bits: WGM22 = 0, WGM21 = 1, WGM20 = 1) |
| // PD7: Normal port operation, OC2A disconnected, (Bits: COM2A1 = 0, COM2A0 = 0) |
| // PD6: Normal port operation, OC2B disconnected, (Bits: COM2B1 = 0, COM2B0 = 0) |
| TCCR2A &= ~((1<<COM2A1)|(1<<COM2A0)|(1<<COM2B1)|(1<<COM2B0)); |
| TCCR2A |= (1<<WGM21)|(1<<WGM20); |
| |
| // Timer/Counter 2 Control Register B |
| |
| // 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 |
| |
| // divider 64 (Bits: CS022 = 1, CS21 = 0, CS20 = 0) |
| TCCR2B &= ~((1<<FOC2A)|(1<<FOC2B)|(1<<CS21)|(1<<CS20)|(1<<WGM22)); |
| TCCR2B |= (1<<CS22); |
| |
| // Initialize the Timer/Counter 2 Register |
| TCNT2 = 0; |
| |
| // Initialize the Output Compare Register A used for PWM generation on port PD7. |
| OCR2A = 10; |
| |
| // Timer/Counter 2 Interrupt Mask Register |
| // Enable timer output compare match A Interrupt only |
| TIMSK2 &= ~((1<<OCIE2B)|(1<<TOIE2)); |
| TIMSK2 |= (1<<OCIE2A); |
| |
| SREG = sreg; |
| } |
| |
| |
| /*****************************************************/ |
| /* Control Servo Position */ |
| /*****************************************************/ |
| |
| ISR(TIMER2_COMPA_vect) // every 256 * 3.2 us = 0.819 us ( on compare match of TCNT2 and OC2A) |
| { |
| 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 |
| |
| #define MULTIPLIER 4 |
| |
| |
| |
| 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 |
| |
| 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); |
| } |
| |
| // 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; |
| } |
| |
| 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); |
| |
| break; |
| |
| case 3: |
| case 2: |
| case 1: |
| |
| 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; |
| |
| 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; |
| |
| default: |
| // do nothing |
| break; |
| } |
| ServoState--; |
| } |
| |