| 0,0 → 1,104 |
|---|
| #include <avr/io.h> |
| #include <avr/interrupt.h> |
| #include "fc.h" |
| #include "eeprom.h" |
| |
| volatile int16_t ServoValue = 0; |
| |
| |
| /*****************************************************/ |
| /* Initialize Timer 2 */ |
| /*****************************************************/ |
| // The timer 2 is used to generate the PWM at PD7 (J7) |
| // to control a camera servo for pitch compensation. |
| void TIMER2_Init(void) |
| { |
| uint8_t sreg = SREG; |
| |
| // disable all interrupts before reconfiguration |
| cli(); |
| |
| // set PD7 as output of the PWM for pitch servo |
| DDRD |=(1<<DDD7); |
| PORTD |= (1<<PORTD7); |
| |
| |
| // Timer/Counter 2 Control Register A |
| |
| // 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) |
| // 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); |
| |
| // Timer/Counter 2 Control Register B |
| |
| // 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 |
| |
| // divider 256 (Bits: CS022 = 1, CS21 = 1, CS20 = 0) |
| TCCR2B &= ~((1<<FOC2A)|(1<<FOC2B)|(1<<CS20)|(1<<WGM22)); |
| TCCR2B |= (1<<CS22)|(1<<CS21); |
| |
| // Initialize the Output Compare Register A used for PWM generation on port PD7. |
| OCR2A = 10; //10 * 12.8us = 1.28 ms high time |
| |
| // Initialize the Timer/Counter 2 Register |
| TCNT2 = 0; |
| |
| // 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 OCR2A * 12.8 us (compare match) |
| { |
| static uint8_t timer = 10; |
| |
| if(!timer--) |
| { |
| // enable PWM on PD7 in non inverting mode |
| TCCR2A &= ~(0<<COM2A0); |
| TCCR2A |= (1<<COM2A1); |
| |
| ServoValue = FCParam.ServoPitchControl; |
| // inverting movment of servo |
| if(ParamSet.ServoPitchCompInvert & 0x01) |
| { |
| ServoValue += ((int32_t) ParamSet.ServoPitchComp * (IntegralPitch / 128)) / 512; |
| } |
| else // non inverting movement of servo |
| { |
| ServoValue -= ((int32_t) ParamSet.ServoPitchComp * (IntegralPitch / 128)) / 512; |
| } |
| |
| // limit servo value to its parameter range definition |
| if(ServoValue < ParamSet.ServoPitchMin) |
| { |
| ServoValue = ParamSet.ServoPitchMin; |
| } |
| else if(ServoValue > ParamSet.ServoPitchMax) |
| { |
| ServoValue = ParamSet.ServoPitchMax; |
| } |
| |
| // update PWM |
| OCR2A = ServoValue; |
| timer = ParamSet.ServoPitchRefresh; |
| } |
| else |
| { |
| // disable PWM at PD7 |
| TCCR2A &= ~((1<<COM2A1)|(1<<COM2A0)); |
| // set PD7 to low |
| PORTD &= ~(1<<PORTD7); |
| } |
| } |