Rev 766 | Show entire file | Ignore whitespace | Details | Blame | Last modification | View Log | RSS feed
| Rev 766 | Rev 783 | ||
|---|---|---|---|
| Line 18... | Line 18... | ||
| 18 | // disable all interrupts before reconfiguration |
18 | // disable all interrupts before reconfiguration |
| 19 | cli(); |
19 | cli(); |
| Line 20... | Line 20... | ||
| 20 | 20 | ||
| 21 | // set PD7 as output of the PWM for pitch servo |
21 | // set PD7 as output of the PWM for pitch servo |
| 22 | DDRD |=(1<<DDD7); |
22 | DDRD |=(1<<DDD7); |
| Line 23... | Line 23... | ||
| 23 | PORTB |= (1<<PORTD7); |
23 | PORTD |= (1<<PORTD7); |
| Line 24... | Line 24... | ||
| 24 | 24 | ||
| 25 | 25 | ||
| 26 | // Timer/Counter 2 Control Register A |
26 | // Timer/Counter 2 Control Register A |
| 27 | 27 | ||
| 28 | // Waveform Generation Mode is Fast PWM (Bits: WGM22 = 0, WGM21 = 1, WGM20 = 1) |
28 | // Waveform Generation Mode is Fast PWM (Bits: WGM22 = 0, WGM21 = 1, WGM20 = 1) |
| Line 29... | Line 29... | ||
| 29 | // PD7: Clear OC2B on Compare Match, set OC2B at BOTTOM, noninverting PWM (Bits: COM2A1 = 1, COM2A0 = 0) |
29 | // PD7: Clear OC2B on Compare Match, set OC2B at BOTTOM, non inverting PWM (Bits: COM2A1 = 1, COM2A0 = 0) |
| Line 30... | Line 30... | ||
| 30 | // PD6: Normal port operation, OC2B disconnected, (Bits: COM2B1 = 0, COM2B0 = 0) |
30 | // PD6: Normal port operation, OC2B disconnected, (Bits: COM2B1 = 0, COM2B0 = 0) |
| 31 | TCCR2A &= ~((1<<COM2B1)|(1<<COM2B0)|(1<<COM2A0)); |
31 | TCCR2A &= ~((1<<COM2B1)|(1<<COM2B0)|(1<<COM2A0)); |
| 32 | TCCR2A |= (1<<COM2A1)|(1<<WGM21)|(1<<WGM20); |
32 | TCCR2A |= (1<<COM2A1)|(1<<WGM21)|(1<<WGM20); |
| 33 | 33 | ||
| 34 | // Timer/Counter 2 Control Register B |
34 | // Timer/Counter 2 Control Register B |
| 35 | 35 | ||
| 36 | // Set clock divider for timer 2 to SYSKLOCK/8 = 20MHz / 8 = 2.5MHz |
36 | // Set clock divider for timer 2 to SYSKLOCK/256 = 20MHz / 256 = 78.128 kHz |
| Line 37... | Line 37... | ||
| 37 | // The timer increments from 0x00 to 0xFF with an update rate of 2.5 MHz, |
37 | // The timer increments from 0x00 to 0xFF with an update rate of 78.128 kHz or 12.8 us |
| 38 | // hence the timer overflow interrupt frequency is 2.5 MHz / 256 = 9.765 kHz or 0.1024 ms |
38 | // hence the timer overflow interrupt frequency is 78.128 kHz / 256 = 305.176 Hz or 3.276 ms |
| Line 39... | Line 39... | ||
| 39 | 39 | ||
| 40 | // divider 8 (Bits: CS022 = 0, CS21 = 1, CS20 = 0) |
40 | // divider 256 (Bits: CS022 = 1, CS21 = 1, CS20 = 0) |
| Line 41... | Line 41... | ||
| 41 | TCCR2B &= ~((1<<FOC2A)|(1<<FOC2B)|(1<<WGM22)); |
41 | TCCR2B &= ~((1<<FOC2A)|(1<<FOC2B)|(1<<CS20)|(1<<WGM22)); |
| Line 57... | Line 57... | ||
| 57 | 57 | ||
| 58 | 58 | ||
| 59 | /*****************************************************/ |
59 | /*****************************************************/ |
| 60 | /* Control Servo Position */ |
60 | /* Control Servo Position */ |
| 61 | /*****************************************************/ |
61 | /*****************************************************/ |
| 62 | ISR(TIMER2_COMPA_vect) // 9.765 kHz |
62 | ISR(TIMER2_COMPA_vect) // every OCR2A * 12.8s (compare match) |
| Line 63... | Line 63... | ||
| 63 | { |
63 | { |
| 64 | static uint8_t timer = 10; |
64 | static uint8_t timer = 10; |
| 65 | 65 | ||
| 66 | if(!timer--) |
66 | if(!timer--) |
| - | 67 | { |
|
| Line 67... | Line 68... | ||
| 67 | { |
68 | // enable PWM on PD7 in non inverting mode |
| 68 | // enable PWM on PD7 in non inverting mode |
69 | TCCR2A &= ~(0<<COM2A0); |
| 69 | TCCR2A = (TCCR2A & 0x3F)|(1<<COM2A1)|(0<<COM2A0); |
70 | TCCR2A |= (1<<COM2A1); |
| 70 | 71 | ||