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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 684 | killagreg | 1 | #include "main.h" |
| 2 | |||
| 3 | |||
| 4 | int16_t ServoValue = 0; |
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| 5 | |||
| 6 | |||
| 7 | /*****************************************************/ |
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| 8 | /* Initialize Timer 2 */ |
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| 9 | /*****************************************************/ |
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| 10 | // The timer 2 is used to generate the PWM at PD7 (J7) |
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| 11 | // to control a camera servo for nick compensation |
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| 12 | void TIMER2_Init(void) |
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| 13 | { |
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| 14 | uint8_t sreg = SREG; |
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| 15 | |||
| 16 | // disable all interrupts before reconfiguration |
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| 17 | cli(); |
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| 18 | |||
| 19 | // set PD7 as output for the PWM |
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| 20 | DDRD |=(1<<DDD7); |
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| 21 | PORTB |= (1<<PORTD7); |
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| 22 | |||
| 23 | |||
| 24 | // Timer/Counter 2 Control Register A |
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| 25 | |||
| 26 | // Waveform Generation Mode is Fast PWM (Bits WGM22 = 0, WGM21 = 1, WGM20 = 1) |
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| 27 | // PD7: Clear OC2B on Compare Match, set OC2B at BOTTOM, noninverting PWM (Bits COM2A1 = 1, COM2A0 = 0) |
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| 28 | // PD6: Normal port operation, OC2B disconnected, (Bits COM2B1 = 0, COM2B0 = 0) |
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| 29 | TCCR2A &= ~((1<<COM2B1)|(1<<COM2B0)|(1<<COM2A0)); |
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| 30 | TCCR2A |= (1<<COM2A1)|(1<<WGM21)|(1<<WGM20); |
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| 31 | |||
| 32 | // Timer/Counter 2 Control Register B |
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| 33 | |||
| 34 | // set clock devider for timer 2 to SYSKLOCK/8 = 20MHz / 8 = 2.5MHz |
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| 35 | // i.e. the timer increments from 0x00 to 0xFF with an update rate of 2.5 MHz |
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| 36 | // hence the timer overflow interrupt frequency is 2.5 MHz / 256 = 9.765 kHz |
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| 37 | |||
| 38 | // devider 8 (Bits CS022 = 0, CS21 = 1, CS20 = 0) |
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| 39 | TCCR2B &= ~((1<<FOC2A)|(1<<FOC2B)|(1<<WGM22)); |
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| 40 | TCCR2B = (TCCR2B & 0xF8)|(0<<CS22)|(1<<CS21)|(0<<CS20); |
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| 41 | |||
| 42 | // initialize the Output Compare Register A used for PWM generation on port PD7 |
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| 43 | OCR2A = 10; |
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| 44 | |||
| 45 | // init Timer/Counter 2 Register |
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| 46 | TCNT2 = 0; |
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| 47 | |||
| 48 | // Timer/Counter 2 Interrupt Mask Register |
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| 49 | // enable timer output compare match A Interrupt only |
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| 50 | TIMSK2 &= ~((1<<OCIE2B)|(1<<TOIE2)); |
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| 51 | TIMSK2 |= (1<<OCIE2A); |
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| 52 | |||
| 53 | SREG = sreg; |
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| 54 | } |
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| 55 | |||
| 56 | |||
| 57 | /*****************************************************/ |
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| 58 | /* Control Servo Position */ |
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| 59 | /*****************************************************/ |
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| 60 | ISR(TIMER2_COMPA_vect) // 9,765 kHz |
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| 61 | { |
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| 62 | static uint8_t timer = 10; |
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| 63 | |||
| 64 | if(!timer--) |
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| 65 | { |
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| 66 | // enable PWM on PD7 in non inverting mode |
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| 67 | TCCR2A = (TCCR2A & 0x3F)|(1<<COM2A1)|(0<<COM2A0); |
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| 68 | |||
| 69 | ServoValue = Parameter_ServoNickControl; |
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| 70 | // inverting movment of servo |
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| 71 | if(EE_Parameter.ServoNickCompInvert & 0x01) |
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| 72 | { |
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| 73 | ServoValue += ((int32_t) EE_Parameter.ServoNickComp * (IntegralNick / 128)) / 512; |
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| 74 | } |
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| 75 | else // non inverting movment of servo |
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| 76 | { |
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| 77 | ServoValue -= ((int32_t) EE_Parameter.ServoNickComp * (IntegralNick / 128)) / 512; |
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| 78 | } |
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| 79 | |||
| 80 | // limit servo value to its parameter range definition |
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| 81 | if(ServoValue < EE_Parameter.ServoNickMin) |
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| 82 | { |
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| 83 | ServoValue = EE_Parameter.ServoNickMin; |
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| 84 | } |
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| 85 | else if(ServoValue > EE_Parameter.ServoNickMax) |
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| 86 | { |
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| 87 | ServoValue = EE_Parameter.ServoNickMax; |
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| 88 | } |
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| 89 | |||
| 90 | // update PWM |
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| 91 | OCR2A = ServoValue; |
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| 92 | timer = EE_Parameter.ServoNickRefresh; |
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| 93 | } |
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| 94 | else |
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| 95 | { |
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| 96 | // disable PWM at PD7 |
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| 97 | TCCR2A &= ~((1<<COM2A1)|(1<<COM2A0)); |
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| 98 | // set PD7 to GND |
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| 99 | PORTD &= ~(1<<PORTD7); |
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| 100 | } |
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| 101 | } |