| 81,7 → 81,6 |
|---|
| // 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 |
| 115,9 → 114,7 |
|---|
| { |
| 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 |
| // at the time the edge was detected |
| 131,7 → 128,7 |
|---|
| // lost frame? |
| if(signal > 8000) |
| { |
| Sum_RC_Quality -= Sum_RC_Quality/2; |
| RC_Quality /= 2; |
| } |
| else |
| //sync gap? (3.52 ms < signal < 25.6 ms) |
| 154,29 → 151,22 |
|---|
| // shift signal to zero symmetric range -154 to 159 |
| 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 |
| { |
| Sum_RC_Quality -= 3*RC_Quality; |
| Sum_RC_Quality += 3*(200 - Noise); |
| if(abs(signal-PPM_in[index]) < 6) |
| { |
| if(RC_Quality < 200) RC_Quality +=10; |
| } |
| else |
| { |
| Sum_RC_Quality -= RC_Quality; |
| Sum_RC_Quality += 200 - Noise; |
| } |
| // calculate exponential history for signal |
| tmp = (3 * (PPM_in[index]) + signal) / 4; |
| if(tmp > signal+1) tmp--; else |
| if(tmp < signal-1) tmp++; |
| // calculate signal difference on good signal level |
| if(RC_Quality >= 170) PPM_diff[index] = ((tmp - PPM_in[index]) / 3) * 3; // cut off lower 3 bit for nois reduction |
| if(RC_Quality >= 195) PPM_diff[index] = ((tmp - PPM_in[index]) / 3) * 3; // cut off lower 3 bit for nois reduction |
| else PPM_diff[index] = 0; |
| PPM_in[index] = tmp; // update channel value |
| } |
| else |
| { // invalid PPM time |
| Sum_RC_Quality /= 8; |
| RC_Quality /= 2; |
| } |
| index++; // next channel |
| // demux sum signal for channels 5 to 7 to J3, J4, J5 |
| 188,8 → 178,7 |
|---|
| } |
| } |
| } |
| if(Sum_RC_Quality < 0) Sum_RC_Quality = 0; |
| RC_Quality = Sum_RC_Quality/128; |
| if(RC_Quality) RC_Quality--; |
| } |
| |
| |