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| 1227 | killagreg | 1 | // ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ |
| 2 | // + Copyright (c) 04.2007 Holger Buss |
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| 3 | // + Nur für den privaten Gebrauch |
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| 4 | // + www.MikroKopter.com |
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| 5 | // ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ |
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| 6 | // + Es gilt für das gesamte Projekt (Hardware, Software, Binärfiles, Sourcecode und Dokumentation), |
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| 7 | // + dass eine Nutzung (auch auszugsweise) nur für den privaten (nicht-kommerziellen) Gebrauch zulässig ist. |
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| 8 | // + Sollten direkte oder indirekte kommerzielle Absichten verfolgt werden, ist mit uns (info@mikrokopter.de) Kontakt |
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| 9 | // + bzgl. der Nutzungsbedingungen aufzunehmen. |
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| 10 | // + Eine kommerzielle Nutzung ist z.B.Verkauf von MikroKoptern, Bestückung und Verkauf von Platinen oder Bausätzen, |
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| 11 | // + Verkauf von Luftbildaufnahmen, usw. |
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| 12 | // ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ |
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| 13 | // + Werden Teile des Quellcodes (mit oder ohne Modifikation) weiterverwendet oder veröffentlicht, |
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| 14 | // + unterliegen sie auch diesen Nutzungsbedingungen und diese Nutzungsbedingungen incl. Copyright müssen dann beiliegen |
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| 15 | // ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ |
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| 16 | // + Sollte die Software (auch auszugesweise) oder sonstige Informationen des MikroKopter-Projekts |
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| 17 | // + auf anderen Webseiten oder sonstigen Medien veröffentlicht werden, muss unsere Webseite "http://www.mikrokopter.de" |
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| 18 | // + eindeutig als Ursprung verlinkt werden |
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| 19 | // ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ |
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| 20 | // + Keine Gewähr auf Fehlerfreiheit, Vollständigkeit oder Funktion |
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| 21 | // + Benutzung auf eigene Gefahr |
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| 22 | // + Wir übernehmen keinerlei Haftung für direkte oder indirekte Personen- oder Sachschäden |
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| 23 | // ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ |
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| 24 | // + Die Portierung der Software (oder Teile davon) auf andere Systeme (ausser der Hardware von www.mikrokopter.de) ist nur |
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| 25 | // + mit unserer Zustimmung zulässig |
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| 26 | // ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ |
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| 27 | // + Die Funktion printf_P() unterliegt ihrer eigenen Lizenz und ist hiervon nicht betroffen |
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| 28 | // ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ |
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| 29 | // + Redistributions of source code (with or without modifications) must retain the above copyright notice, |
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| 30 | // + this list of conditions and the following disclaimer. |
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| 31 | // + * Neither the name of the copyright holders nor the names of contributors may be used to endorse or promote products derived |
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| 32 | // + from this software without specific prior written permission. |
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| 33 | // + * The use of this project (hardware, software, binary files, sources and documentation) is only permittet |
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| 34 | // + for non-commercial use (directly or indirectly) |
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| 35 | // + Commercial use (for excample: selling of MikroKopters, selling of PCBs, assembly, ...) is only permitted |
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| 36 | // + with our written permission |
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| 37 | // + * If sources or documentations are redistributet on other webpages, out webpage (http://www.MikroKopter.de) must be |
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| 38 | // + clearly linked as origin |
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| 39 | // + * porting to systems other than hardware from www.mikrokopter.de is not allowed |
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| 40 | // + THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" |
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| 41 | // + AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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| 42 | // + IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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| 43 | // + ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE |
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| 44 | // + LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
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| 45 | // + CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
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| 46 | // + SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
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| 47 | // + INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN// + CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
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| 48 | // + ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
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| 49 | // + POSSIBILITY OF SUCH DAMAGE. |
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| 50 | // ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ |
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| 51 | #include <stdlib.h> |
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| 52 | #include <avr/io.h> |
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| 53 | #include <avr/interrupt.h> |
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| 54 | |||
| 55 | #include "rc.h" |
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| 56 | #include "main.h" |
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| 57 | |||
| 58 | volatile int16_t PPM_in[15]; //PPM24 supports 12 channels per frame |
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| 59 | volatile int16_t PPM_diff[15]; |
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| 60 | volatile uint8_t NewPpmData = 1; |
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| 61 | volatile int16_t RC_Quality = 0; |
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| 62 | |||
| 63 | |||
| 64 | |||
| 65 | /***************************************************************/ |
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| 66 | /* 16bit timer 1 is used to decode the PPM-Signal */ |
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| 67 | /***************************************************************/ |
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| 68 | void RC_Init (void) |
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| 69 | { |
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| 70 | uint8_t sreg = SREG; |
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| 71 | |||
| 72 | // disable all interrupts before reconfiguration |
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| 73 | cli(); |
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| 74 | |||
| 75 | // PPM-signal is connected to the Input Capture Pin (PD6) of timer 1 |
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| 76 | DDRD &= ~(1<<DDD6); |
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| 77 | PORTD |= (1<<PORTD6); |
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| 78 | |||
| 79 | // Channel 5,6,7 is decoded to servo signals at pin PD5 (J3), PD4(J4), PD3(J5) |
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| 80 | // set as output |
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| 81 | DDRD |= (1<<DDD5)|(1<<DDD4); |
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| 82 | // low level |
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| 83 | PORTD &= ~((1<<PORTD5)|(1<<PORTD4)); |
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| 84 | |||
| 85 | // PD3 can't be used if 2nd UART is activated |
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| 86 | // because TXD1 is at that port |
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| 87 | if(CPUType != ATMEGA644P) |
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| 88 | { |
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| 89 | DDRD |= (1<<PORTD3); |
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| 90 | PORTD &= ~(1<<PORTD3); |
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| 91 | } |
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| 92 | |||
| 93 | // Timer/Counter1 Control Register A, B, C |
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| 94 | |||
| 95 | // Normal Mode (bits: WGM13=0, WGM12=0, WGM11=0, WGM10=0) |
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| 96 | // Compare output pin A & B is disabled (bits: COM1A1=0, COM1A0=0, COM1B1=0, COM1B0=0) |
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| 97 | // Set clock source to SYSCLK/64 (bit: CS12=0, CS11=1, CS10=1) |
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| 98 | // Enable input capture noise cancler (bit: ICNC1=1) |
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| 99 | // Trigger on positive edge of the input capture pin (bit: ICES1=1), |
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| 100 | // Therefore the counter incremets at a clock of 20 MHz/64 = 312.5 kHz or 3.2µs |
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| 101 | // The longest period is 0xFFFF / 312.5 kHz = 0.209712 s. |
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| 102 | TCCR1A &= ~((1<<COM1A1)|(1<<COM1A0)|(1<<COM1B1)|(1<<COM1B0)|(1<<WGM11)|(1<<WGM10)); |
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| 103 | TCCR1B &= ~((1<<WGM13)|(1<<WGM12)|(1<<CS12)); |
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| 104 | TCCR1B |= (1<<CS11)|(1<<CS10)|(1<<ICES1)|(1<<ICNC1); |
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| 105 | TCCR1C &= ~((1<<FOC1A)|(1<<FOC1B)); |
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| 106 | |||
| 107 | // Timer/Counter1 Interrupt Mask Register |
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| 108 | |||
| 109 | // Enable Input Capture Interrupt (bit: ICIE1=1) |
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| 110 | // Disable Output Compare A & B Match Interrupts (bit: OCIE1B=0, OICIE1A=0) |
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| 111 | // Enable Overflow Interrupt (bit: TOIE1=0) |
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| 112 | TIMSK1 &= ~((1<<OCIE1B)|(1<<OCIE1A)|(1<<TOIE1)); |
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| 113 | TIMSK1 |= (1<<ICIE1); |
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| 114 | |||
| 115 | RC_Quality = 0; |
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| 116 | |||
| 117 | SREG = sreg; |
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| 118 | } |
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| 119 | |||
| 120 | |||
| 121 | /********************************************************************/ |
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| 122 | /* Every time a positive edge is detected at PD6 */ |
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| 123 | /********************************************************************/ |
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| 124 | /* t-Frame |
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| 125 | <-----------------------------------------------------------------------> |
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| 126 | ____ ______ _____ ________ ______ sync gap ____ |
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| 127 | | | | | | | | | | | | |
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| 128 | | | | | | | | | | | | |
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| 129 | ___| |_| |_| |_| |_.............| |________________| |
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| 130 | <-----><-------><------><--------> <------> <--- |
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| 131 | t0 t1 t2 t4 tn t0 |
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| 132 | |||
| 133 | The PPM-Frame length is 22.5 ms. |
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| 134 | Channel high pulse width range is 0.7 ms to 1.7 ms completed by an 0.3 ms low pulse. |
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| 135 | The mininimum time delay of two events coding a channel is ( 0.7 + 0.3) ms = 1 ms. |
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| 136 | The maximum time delay of two events coding a chanel is ( 1.7 + 0.3) ms = 2 ms. |
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| 137 | The minimum duration of all channels at minimum value is 8 * 1 ms = 8 ms. |
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| 138 | The maximum duration of all channels at maximum value is 8 * 2 ms = 16 ms. |
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| 139 | The remaining time of (22.5 - 8 ms) ms = 14.5 ms to (22.5 - 16 ms) ms = 6.5 ms is |
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| 140 | the syncronization gap. |
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| 141 | */ |
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| 142 | ISR(TIMER1_CAPT_vect) // typical rate of 1 ms to 2 ms |
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| 143 | { |
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| 144 | int16_t signal = 0, tmp; |
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| 145 | static int16_t index; |
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| 146 | static uint16_t oldICR1 = 0; |
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| 147 | |||
| 148 | // 16bit Input Capture Register ICR1 contains the timer value TCNT1 |
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| 149 | // at the time the edge was detected |
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| 150 | |||
| 151 | // calculate the time delay to the previous event time which is stored in oldICR1 |
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| 152 | // calculatiing the difference of the two uint16_t and converting the result to an int16_t |
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| 153 | // implicit handles a timer overflow 65535 -> 0 the right way. |
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| 154 | signal = (uint16_t) ICR1 - oldICR1; |
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| 155 | oldICR1 = ICR1; |
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| 156 | |||
| 157 | //sync gap? (3.52 ms < signal < 25.6 ms) |
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| 158 | if((signal > 1100) && (signal < 8000)) |
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| 159 | { |
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| 160 | // if a sync gap happens and there where at least 4 channels decoded before |
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| 161 | // then the NewPpmData flag is reset indicating valid data in the PPM_in[] array. |
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| 162 | if(index >= 4) |
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| 163 | { |
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| 164 | NewPpmData = 0; // Null means NewData for the first 4 channels |
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| 165 | } |
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| 166 | // synchronize channel index |
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| 167 | index = 1; |
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| 168 | } |
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| 169 | else // within the PPM frame |
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| 170 | { |
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| 171 | if(index < 14) // PPM24 supports 12 channels |
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| 172 | { |
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| 173 | // check for valid signal length (0.8 ms < signal < 2.1984 ms) |
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| 174 | // signal range is from 1.0ms/3.2us = 312 to 2.0ms/3.2us = 625 |
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| 175 | if((signal > 250) && (signal < 687)) |
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| 176 | { |
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| 177 | // shift signal to zero symmetric range -154 to 159 |
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| 178 | signal -= 466; // offset of 1.4912 ms ??? (469 * 3.2µs = 1.5008 ms) |
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| 179 | // check for stable signal |
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| 180 | if(abs(signal - PPM_in[index]) < 6) |
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| 181 | { |
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| 182 | if(RC_Quality < 200) RC_Quality +=10; |
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| 183 | else RC_Quality = 200; |
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| 184 | } |
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| 185 | // calculate exponential history for signal |
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| 186 | tmp = (3 * (PPM_in[index]) + signal) / 4; |
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| 187 | if(tmp > signal+1) tmp--; else |
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| 188 | if(tmp < signal-1) tmp++; |
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| 189 | // calculate signal difference on good signal level |
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| 190 | if(RC_Quality >= 195) PPM_diff[index] = ((tmp - PPM_in[index]) / 3) * 3; // cut off lower 3 bit for nois reduction |
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| 191 | else PPM_diff[index] = 0; |
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| 192 | PPM_in[index] = tmp; // update channel value |
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| 193 | } |
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| 194 | index++; // next channel |
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| 195 | // demux sum signal for channels 5 to 7 to J3, J4, J5 |
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| 196 | if(index == 5) J3HIGH; else J3LOW; |
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| 197 | if(index == 6) J4HIGH; else J3LOW; |
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| 198 | if(CPUType != ATMEGA644P) // not used as TXD1 |
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| 199 | { |
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| 200 | if(index == 7) J5HIGH; else J5LOW; |
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| 201 | } |
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| 202 | } |
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| 203 | } |
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| 204 | } |
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| 205 | |||
| 206 | |||
| 207 | |||
| 208 | |||
| 209 |