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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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1235 | killagreg | 197 | if(index == 6) J4HIGH; else J4LOW; |
1227 | killagreg | 198 | if(CPUType != ATMEGA644P) // not used as TXD1 |
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 |