| 67,9 → 67,9 |
|---|
| |
| // Enable Input Capture Interrupt (bit: ICIE1=1) |
| // Disable Output Compare A & B Match Interrupts (bit: OCIE1B=0, OICIE1A=0) |
| // Disable Overflow Interrupt (bit: TOIE1=0) |
| TIMSK1 &= ~((1<<OCIE1B)|(1<<OCIE1A)|(1<<TOIE1)); |
| TIMSK1 |= (1<<ICIE1); |
| // Enable Overflow Interrupt (bit: TOIE1=0) |
| TIMSK1 &= ~((1<<OCIE1B)|(1<<OCIE1A)); |
| TIMSK1 |= (1<<ICIE1)|(1<<TOIE1); |
| |
| RC_Quality = 0; |
| |
| 77,6 → 77,19 |
|---|
| } |
| |
| |
| // happens every 0.209712 s. |
| // check for at least one input capture event per timer overflow (timeout) |
| ISR(TIMER1_OVF_vect) |
| { |
| int16_t signal = 0; |
| static uint16_t lastICR1 = 0; |
| // if ICR1 has not changed |
| // then no new input capture event has occured since last timer overflow |
| if (lastICR1 == ICR1) RC_Quality = 0; |
| lastICR1 = ICR1; // store last ICR1 |
| } |
| |
| |
| /********************************************************************/ |
| /* Every time a positive edge is detected at PD6 */ |
| /********************************************************************/ |
| 100,10 → 113,10 |
|---|
| */ |
| ISR(TIMER1_CAPT_vect) // typical rate of 1 ms to 2 ms |
| { |
| static uint16_t oldICR1 = 0; |
| int16_t signal = 0, tmp; |
| static int16_t index; |
| static int16_t Sum_RC_Quality = 0; |
| static uint16_t oldICR1 = 0; |
| int16_t Noise; |
| |
| // 16bit Input Capture Register ICR1 contains the timer value TCNT1 |
| 115,7 → 128,12 |
|---|
| signal = (uint16_t) ICR1 - oldICR1; |
| oldICR1 = ICR1; |
| |
| |
| // lost frame |
| if(signal > 8000) |
| { |
| Sum_RC_Quality -= Sum_RC_Quality/2; |
| } |
| else |
| //sync gap? (3.52 ms < signal < 25.6 ms) |
| if((signal > 1100) && (signal < 8000)) |
| { |
| 126,7 → 144,7 |
|---|
| index = 1; |
| } |
| else // within the PPM frame |
| { |
| { |
| if(index < 14) // PPM24 supports 12 channels |
| { |
| // check for valid signal length (0.8 ms < signal < 2.1984 ms) |
| 137,7 → 155,8 |
|---|
| signal -= 466; // offset of 1.4912 ms ??? (469 * 3.2µs = 1.5008 ms) |
| // check for stable signal |
| Noise = abs(signal - PPM_in[index]); |
| if((Noise/16) > (200-RC_Quality)) // spike detector |
| if (Noise > 150) Sum_RC_Quality /= 2; |
| else if((Noise/16) > (200-RC_Quality)) // spike detector |
| { |
| Sum_RC_Quality -= 3*RC_Quality; |
| Sum_RC_Quality += 3*(200 - Noise); |
| 158,10 → 177,8 |
|---|
| } |
| else |
| { // invalid PPM time |
| Sum_RC_Quality -= Sum_RC_Quality/4; |
| Sum_RC_Quality /= 2; |
| } |
| if(Sum_RC_Quality < 0) Sum_RC_Quality = 0; |
| RC_Quality = Sum_RC_Quality/128; |
| index++; // next channel |
| // demux sum signal for channels 5 to 7 to J3, J4, J5 |
| if(index == 5) PORTD |= (1<<PORTD5); else PORTD &= ~(1<<PORTD5); |
| 172,6 → 189,8 |
|---|
| } |
| } |
| } |
| if(Sum_RC_Quality < 0) Sum_RC_Quality = 0; |
| RC_Quality = Sum_RC_Quality/128; |
| } |
| |
| |