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| Rev 766 | Rev 800 | ||
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| Line 16... | Line 16... | ||
| 16 | #include "main.h" |
16 | #include "main.h" |
| Line 17... | Line 17... | ||
| 17 | 17 | ||
| 18 | volatile int16_t PPM_in[15]; //PPM24 supports 12 channels per frame |
18 | volatile int16_t PPM_in[15]; //PPM24 supports 12 channels per frame |
| 19 | volatile int16_t PPM_diff[15]; |
19 | volatile int16_t PPM_diff[15]; |
| 20 | volatile uint8_t NewPpmData = 1; |
20 | volatile uint8_t NewPpmData = 1; |
| - | 21 | volatile uint8_t RC_Quality = 0; |
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| Line 21... | Line 22... | ||
| 21 | volatile uint8_t SenderOkay = 0; |
22 | |
| 22 | 23 | ||
| 23 | /***************************************************************/ |
24 | /***************************************************************/ |
| 24 | /* 16bit timer 1 is used to decode the PPM-Signal */ |
25 | /* 16bit timer 1 is used to decode the PPM-Signal */ |
| Line 68... | Line 69... | ||
| 68 | // Disable Output Compare A & B Match Interrupts (bit: OCIE1B=0, OICIE1A=0) |
69 | // Disable Output Compare A & B Match Interrupts (bit: OCIE1B=0, OICIE1A=0) |
| 69 | // Disable Overflow Interrupt (bit: TOIE1=0) |
70 | // Disable Overflow Interrupt (bit: TOIE1=0) |
| 70 | TIMSK1 &= ~((1<<OCIE1B)|(1<<OCIE1A)|(1<<TOIE1)); |
71 | TIMSK1 &= ~((1<<OCIE1B)|(1<<OCIE1A)|(1<<TOIE1)); |
| 71 | TIMSK1 |= (1<<ICIE1); |
72 | TIMSK1 |= (1<<ICIE1); |
| Line -... | Line 73... | ||
| - | 73 | ||
| - | 74 | RC_Quality = 0; |
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| 72 | 75 | ||
| 73 | SREG = sreg; |
76 | SREG = sreg; |
| Line 74... | Line 77... | ||
| 74 | } |
77 | } |
| Line 98... | Line 101... | ||
| 98 | ISR(TIMER1_CAPT_vect) // typical rate of 1 ms to 2 ms |
101 | ISR(TIMER1_CAPT_vect) // typical rate of 1 ms to 2 ms |
| 99 | { |
102 | { |
| 100 | static uint16_t oldICR1 = 0; |
103 | static uint16_t oldICR1 = 0; |
| 101 | int16_t signal = 0, tmp; |
104 | int16_t signal = 0, tmp; |
| 102 | static int16_t index; |
105 | static int16_t index; |
| - | 106 | static int16_t Sum_RC_Quality = 0; |
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| Line 103... | Line 107... | ||
| 103 | 107 | ||
| 104 | // 16bit Input Capture Register ICR1 contains the timer value TCNT1 |
108 | // 16bit Input Capture Register ICR1 contains the timer value TCNT1 |
| Line 105... | Line 109... | ||
| 105 | // at the time the edge was detected |
109 | // at the time the edge was detected |
| - | 110 | ||
| - | 111 | // calculate the time delay to the previous event time which is stored in oldICR1 |
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| 106 | 112 | // calculatiing the difference of the two uint16_t and converting the result to an int16_t |
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| 107 | // calculate the time delay to the previous event time which is stored in oldICR1 |
113 | // implicit handles a timer overflow 65535 -> 0 the right way. |
| Line 108... | Line 114... | ||
| 108 | signal = (uint16_t) ICR1 - oldICR1; |
114 | signal = (uint16_t) ICR1 - oldICR1; |
| Line 127... | Line 133... | ||
| 127 | if((signal > 250) && (signal < 687)) |
133 | if((signal > 250) && (signal < 687)) |
| 128 | { |
134 | { |
| 129 | // shift signal to zero symmetric range -154 to 159 |
135 | // shift signal to zero symmetric range -154 to 159 |
| 130 | signal -= 466; // offset of 1.4912 ms ??? (469 * 3.2µs = 1.5008 ms) |
136 | signal -= 466; // offset of 1.4912 ms ??? (469 * 3.2µs = 1.5008 ms) |
| 131 | // check for stable signal |
137 | // check for stable signal |
| 132 | // the deviation of the current signal level from the average must be less than 6 (aprox. 1%) |
- | |
| 133 | if(abs(signal - PPM_in[index]) < 6) |
- | |
| 134 | { |
- | |
| 135 | // a good signal condition increases SenderOkay by 10 |
- | |
| 136 | // SignalOkay is decremented every 2 ms in main.c |
138 | Sum_RC_Quality -= Sum_RC_Quality/128; |
| 137 | // this variable is a level for the average rate of a noiseless rc signal |
139 | Sum_RC_Quality += 200 - abs(signal - PPM_in[index]); // max 200*128 = 25600 |
| 138 | if(SenderOkay < 200) SenderOkay += 10; |
- | |
| 139 | } |
- | |
| 140 | // calculate exponential history for signal |
140 | // calculate exponential history for signal |
| 141 | tmp = (3 * (PPM_in[index]) + signal) / 4; |
141 | tmp = (3 * (PPM_in[index]) + signal) / 4; |
| 142 | if(tmp > signal+1) tmp--; else |
142 | if(tmp > signal+1) tmp--; else |
| 143 | if(tmp < signal-1) tmp++; |
143 | if(tmp < signal-1) tmp++; |
| 144 | // calculate signal difference on good signal level |
144 | // calculate signal difference on good signal level |
| 145 | if(SenderOkay >= 195) PPM_diff[index] = ((tmp - PPM_in[index]) / 3) * 3; // cut off lower 3 bit for nois reduction |
145 | if(RC_Quality >= 170) PPM_diff[index] = ((tmp - PPM_in[index]) / 3) * 3; // cut off lower 3 bit for nois reduction |
| 146 | else PPM_diff[index] = 0; |
146 | else PPM_diff[index] = 0; |
| 147 | PPM_in[index] = tmp; // update channel value |
147 | PPM_in[index] = tmp; // update channel value |
| 148 | } |
148 | } |
| - | 149 | else |
|
| - | 150 | { // invalid PPM time |
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| - | 151 | Sum_RC_Quality -= Sum_RC_Quality/4; |
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| - | 152 | } |
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| - | 153 | if(Sum_RC_Quality < 0) Sum_RC_Quality = 0; |
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| - | 154 | RC_Quality = (uint8_t)(Sum_RC_Quality/128); |
|
| 149 | index++; // next channel |
155 | index++; // next channel |
| 150 | // demux sum signal for channels 5 to 7 to J3, J4, J5 |
156 | // demux sum signal for channels 5 to 7 to J3, J4, J5 |
| 151 | if(index == 5) PORTD |= (1<<PORTD5); else PORTD &= ~(1<<PORTD5); |
157 | if(index == 5) PORTD |= (1<<PORTD5); else PORTD &= ~(1<<PORTD5); |
| 152 | if(index == 6) PORTD |= (1<<PORTD4); else PORTD &= ~(1<<PORTD4); |
158 | if(index == 6) PORTD |= (1<<PORTD4); else PORTD &= ~(1<<PORTD4); |
| 153 | if(BoardRelease == 10) |
159 | if(BoardRelease == 10) |