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1 | /*####################################################################################### |
1 | /*####################################################################################### |
2 | Decodieren eines RC Summen Signals |
2 | Decodieren eines RC Summen Signals |
3 | #######################################################################################*/ |
3 | #######################################################################################*/ |
4 | // ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ |
4 | // ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ |
5 | // + Copyright (c) 04.2007 Holger Buss |
5 | // + Copyright (c) 04.2007 Holger Buss |
6 | // + only for non-profit use |
6 | // + only for non-profit use |
7 | // + www.MikroKopter.com |
7 | // + www.MikroKopter.com |
8 | // + see the File "License.txt" for further Informations |
8 | // + see the File "License.txt" for further Informations |
9 | // ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ |
9 | // ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ |
10 | 10 | ||
11 | #include <stdlib.h> |
11 | #include <stdlib.h> |
12 | #include <avr/io.h> |
12 | #include <avr/io.h> |
13 | #include <avr/interrupt.h> |
13 | #include <avr/interrupt.h> |
14 | 14 | ||
15 | #include "rc.h" |
15 | #include "rc.h" |
16 | #include "main.h" |
16 | #include "main.h" |
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 SenderOkay = 0; |
21 | volatile uint8_t RC_Quality = 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 */ |
25 | /***************************************************************/ |
26 | /***************************************************************/ |
26 | void RC_Init (void) |
27 | void RC_Init (void) |
27 | { |
28 | { |
28 | uint8_t sreg = SREG; |
29 | uint8_t sreg = SREG; |
29 | 30 | ||
30 | // disable all interrupts before reconfiguration |
31 | // disable all interrupts before reconfiguration |
31 | cli(); |
32 | cli(); |
32 | 33 | ||
33 | // PPM-signal is connected to the Input Capture Pin (PD6) of timer 1 |
34 | // PPM-signal is connected to the Input Capture Pin (PD6) of timer 1 |
34 | DDRD &= ~(1<<DDD6); |
35 | DDRD &= ~(1<<DDD6); |
35 | PORTD |= (1<<PORTD6); |
36 | PORTD |= (1<<PORTD6); |
36 | 37 | ||
37 | // Channel 5,6,7 is decoded to servo signals at pin PD5 (J3), PD4(J4), PD3(J5) |
38 | // Channel 5,6,7 is decoded to servo signals at pin PD5 (J3), PD4(J4), PD3(J5) |
38 | // set as output |
39 | // set as output |
39 | DDRD |= (1<<DDD5)|(1<<DDD4); |
40 | DDRD |= (1<<DDD5)|(1<<DDD4); |
40 | // low level |
41 | // low level |
41 | PORTD &= ~((1<<PORTD5)|(1<<PORTD4)); |
42 | PORTD &= ~((1<<PORTD5)|(1<<PORTD4)); |
42 | 43 | ||
43 | // PD3 can't be used in FC 1.1 if 2nd UART is activated |
44 | // PD3 can't be used in FC 1.1 if 2nd UART is activated |
44 | // because TXD1 is at that port |
45 | // because TXD1 is at that port |
45 | if(BoardRelease == 10) |
46 | if(BoardRelease == 10) |
46 | { |
47 | { |
47 | DDRD |= (1<<PORTD3); |
48 | DDRD |= (1<<PORTD3); |
48 | PORTD &= ~(1<<PORTD3); |
49 | PORTD &= ~(1<<PORTD3); |
49 | } |
50 | } |
50 | 51 | ||
51 | // Timer/Counter1 Control Register A, B, C |
52 | // Timer/Counter1 Control Register A, B, C |
52 | 53 | ||
53 | // Normal Mode (bits: WGM13=0, WGM12=0, WGM11=0, WGM10=0) |
54 | // Normal Mode (bits: WGM13=0, WGM12=0, WGM11=0, WGM10=0) |
54 | // Compare output pin A & B is disabled (bits: COM1A1=0, COM1A0=0, COM1B1=0, COM1B0=0) |
55 | // Compare output pin A & B is disabled (bits: COM1A1=0, COM1A0=0, COM1B1=0, COM1B0=0) |
55 | // Set clock source to SYSCLK/64 (bit: CS12=0, CS11=1, CS10=1) |
56 | // Set clock source to SYSCLK/64 (bit: CS12=0, CS11=1, CS10=1) |
56 | // Enable input capture noise cancler (bit: ICNC1=1) |
57 | // Enable input capture noise cancler (bit: ICNC1=1) |
57 | // Trigger on positive edge of the input capture pin (bit: ICES1=1), |
58 | // Trigger on positive edge of the input capture pin (bit: ICES1=1), |
58 | // Therefore the counter incremets at a clock of 20 MHz/64 = 312.5 kHz or 3.2µs |
59 | // Therefore the counter incremets at a clock of 20 MHz/64 = 312.5 kHz or 3.2µs |
59 | // The longest period is 0xFFFF / 312.5 kHz = 0.209712 s. |
60 | // The longest period is 0xFFFF / 312.5 kHz = 0.209712 s. |
60 | TCCR1A &= ~((1<<COM1A1)|(1<<COM1A0)|(1<<COM1B1)|(1<<COM1B0)|(1<<WGM11)|(1<<WGM10)); |
61 | TCCR1A &= ~((1<<COM1A1)|(1<<COM1A0)|(1<<COM1B1)|(1<<COM1B0)|(1<<WGM11)|(1<<WGM10)); |
61 | TCCR1B &= ~((1<<WGM13)|(1<<WGM12)|(1<<CS12)); |
62 | TCCR1B &= ~((1<<WGM13)|(1<<WGM12)|(1<<CS12)); |
62 | TCCR1B |= (1<<CS11)|(1<<CS10)|(1<<ICES1)|(1<<ICNC1); |
63 | TCCR1B |= (1<<CS11)|(1<<CS10)|(1<<ICES1)|(1<<ICNC1); |
63 | TCCR1C &= ~((1<<FOC1A)|(1<<FOC1B)); |
64 | TCCR1C &= ~((1<<FOC1A)|(1<<FOC1B)); |
64 | 65 | ||
65 | // Timer/Counter1 Interrupt Mask Register |
66 | // Timer/Counter1 Interrupt Mask Register |
66 | 67 | ||
67 | // Enable Input Capture Interrupt (bit: ICIE1=1) |
68 | // Enable Input Capture Interrupt (bit: ICIE1=1) |
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); |
- | 73 | ||
- | 74 | RC_Quality = 0; |
|
72 | 75 | ||
73 | SREG = sreg; |
76 | SREG = sreg; |
74 | } |
77 | } |
75 | 78 | ||
76 | 79 | ||
77 | /********************************************************************/ |
80 | /********************************************************************/ |
78 | /* Every time a positive edge is detected at PD6 */ |
81 | /* Every time a positive edge is detected at PD6 */ |
79 | /********************************************************************/ |
82 | /********************************************************************/ |
80 | /* t-Frame |
83 | /* t-Frame |
81 | <-----------------------------------------------------------------------> |
84 | <-----------------------------------------------------------------------> |
82 | ____ ______ _____ ________ ______ sync gap ____ |
85 | ____ ______ _____ ________ ______ sync gap ____ |
83 | | | | | | | | | | | | |
86 | | | | | | | | | | | | |
84 | | | | | | | | | | | | |
87 | | | | | | | | | | | | |
85 | ___| |_| |_| |_| |_.............| |________________| |
88 | ___| |_| |_| |_| |_.............| |________________| |
86 | <-----><-------><------><--------> <------> <--- |
89 | <-----><-------><------><--------> <------> <--- |
87 | t0 t1 t2 t4 tn t0 |
90 | t0 t1 t2 t4 tn t0 |
88 | 91 | ||
89 | The PPM-Frame length is 22.5 ms. |
92 | The PPM-Frame length is 22.5 ms. |
90 | Channel high pulse width range is 0.7 ms to 1.7 ms completed by an 0.3 ms low pulse. |
93 | Channel high pulse width range is 0.7 ms to 1.7 ms completed by an 0.3 ms low pulse. |
91 | The mininimum time delay of two events coding a channel is ( 0.7 + 0.3) ms = 1 ms. |
94 | The mininimum time delay of two events coding a channel is ( 0.7 + 0.3) ms = 1 ms. |
92 | The maximum time delay of two events coding a chanel is ( 1.7 + 0.3) ms = 2 ms. |
95 | The maximum time delay of two events coding a chanel is ( 1.7 + 0.3) ms = 2 ms. |
93 | The minimum duration of all channels at minimum value is 8 * 1 ms = 8 ms. |
96 | The minimum duration of all channels at minimum value is 8 * 1 ms = 8 ms. |
94 | The maximum duration of all channels at maximum value is 8 * 2 ms = 16 ms. |
97 | The maximum duration of all channels at maximum value is 8 * 2 ms = 16 ms. |
95 | The remaining time of (22.5 - 8 ms) ms = 14.5 ms to (22.5 - 16 ms) ms = 6.5 ms is |
98 | The remaining time of (22.5 - 8 ms) ms = 14.5 ms to (22.5 - 16 ms) ms = 6.5 ms is |
96 | the syncronization gap. |
99 | the syncronization gap. |
97 | */ |
100 | */ |
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; |
|
103 | 107 | ||
104 | // 16bit Input Capture Register ICR1 contains the timer value TCNT1 |
108 | // 16bit Input Capture Register ICR1 contains the timer value TCNT1 |
105 | // at the time the edge was detected |
109 | // at the time the edge was detected |
106 | 110 | ||
107 | // calculate the time delay to the previous event time which is stored in oldICR1 |
111 | // calculate the time delay to the previous event time which is stored in oldICR1 |
- | 112 | // calculatiing the difference of the two uint16_t and converting the result to an int16_t |
|
- | 113 | // implicit handles a timer overflow 65535 -> 0 the right way. |
|
108 | signal = (uint16_t) ICR1 - oldICR1; |
114 | signal = (uint16_t) ICR1 - oldICR1; |
109 | oldICR1 = ICR1; |
115 | oldICR1 = ICR1; |
110 | 116 | ||
111 | 117 | ||
112 | //sync gap? (3.52 ms < signal < 25.6 ms) |
118 | //sync gap? (3.52 ms < signal < 25.6 ms) |
113 | if((signal > 1100) && (signal < 8000)) |
119 | if((signal > 1100) && (signal < 8000)) |
114 | { |
120 | { |
115 | // if a sync gap happens and there where at least 4 channels decoded before |
121 | // if a sync gap happens and there where at least 4 channels decoded before |
116 | // then the NewPpmData flag is reset indicating valid data in the PPM_in[] array. |
122 | // then the NewPpmData flag is reset indicating valid data in the PPM_in[] array. |
117 | if(index >= 4) NewPpmData = 0; // Null means NewData for the first 4 channels |
123 | if(index >= 4) NewPpmData = 0; // Null means NewData for the first 4 channels |
118 | // synchronize channel index |
124 | // synchronize channel index |
119 | index = 1; |
125 | index = 1; |
120 | } |
126 | } |
121 | else // within the PPM frame |
127 | else // within the PPM frame |
122 | { |
128 | { |
123 | if(index < 14) // PPM24 supports 12 channels |
129 | if(index < 14) // PPM24 supports 12 channels |
124 | { |
130 | { |
125 | // check for valid signal length (0.8 ms < signal < 2.1984 ms) |
131 | // check for valid signal length (0.8 ms < signal < 2.1984 ms) |
126 | // signal range is from 1.0ms/3.2us = 312 to 2.0ms/3.2us = 625 |
132 | // signal range is from 1.0ms/3.2us = 312 to 2.0ms/3.2us = 625 |
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 |
|
- | 151 | Sum_RC_Quality -= Sum_RC_Quality/4; |
|
- | 152 | } |
|
- | 153 | if(Sum_RC_Quality < 0) Sum_RC_Quality = 0; |
|
- | 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) |
154 | { |
160 | { |
155 | if(index == 7) PORTD |= (1<<PORTD3); else PORTD &= ~(1<<PORTD3); |
161 | if(index == 7) PORTD |= (1<<PORTD3); else PORTD &= ~(1<<PORTD3); |
156 | } |
162 | } |
157 | } |
163 | } |
158 | } |
164 | } |
159 | } |
165 | } |
160 | 166 | ||
161 | 167 | ||
162 | 168 | ||
163 | 169 | ||
164 | 170 | ||
165 | 171 |