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Rev | Author | Line No. | Line |
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1199 | killagreg | 1 | #include "dsl.h" |
1200 | killagreg | 2 | #include "rc.h" |
1199 | killagreg | 3 | |
4 | /* |
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1206 | killagreg | 5 | Connection of DSL to SV1 of FC: |
6 | ( DSL Pin1 is on side of channel 4 ) |
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1199 | killagreg | 7 | |
1206 | killagreg | 8 | 1. GND <--> pin 7 (GND) |
9 | 2. TXD <--> pin 3 (RXD1 Atmega644p) |
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10 | 3. RXD <--> pin 4 (TXD1 Atmega644p) optional |
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11 | 4. 5V <--> pin 2 (5V) |
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1199 | killagreg | 12 | |
1206 | killagreg | 13 | Do not connect the receiver via PPM-Sumsignal output the same time. |
1199 | killagreg | 14 | |
1206 | killagreg | 15 | Data are send at 38400baud8n1 |
1199 | killagreg | 16 | |
1206 | killagreg | 17 | Data Frame: |0xFF|0xFF|0x1F|FREQALLOC|??|RSSI|VBAT|??|CRC|10|CH0D1|CH0D0|CH1D1|CH1D0|CRC| ...etc |
18 | |||
19 | FREQALLOC = 35, 40, 72 |
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20 | RSSI = 0.. 255 // Received signal strength indicator |
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21 | VBAT = 0...255 // supply voltage (0.0V.. 8.2V) |
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22 | |||
23 | Servo Pair: |0x1X|CHXD1|CHXD0|CHX+1D1|CHX+1D0|CRC| |
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24 | X is channel index of 1 servo value |
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25 | D1D0 is servo value as u16 in range of 7373 (1ms) to 14745 (2ms) |
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26 | there are 8 channels submitted, i.e 4 servo pairs |
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27 | |||
28 | |||
29 | Frame examples with signel received |
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30 | |||
31 | FFFF 1F23F079A304AD 1036012B1E6F 122AFB2AECB2 142B4D2B4404 1636872B33CE |
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32 | FFFF 1F23F079A304AD 1036002B1F6F 122AFE2AEBB0 142B4B2B4406 1636872B33CE |
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33 | FFFF 1F23F079A304AD 1035FF2B226E 122AFC2AEAB3 142B4E2B4304 1636882B33CD |
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34 | FFFF 1F23F079A304AD 1036022B1E6E 122AFB2AEEB0 142B4A2B4506 1636872B33CE |
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35 | FFFF 1F23F079A304AD 1036022B1E6E 122AFE2AEBB0 142B4B2B4406 1636882B33CD |
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36 | FFFF 1F23F079A304AD 1036012B1E6F 122AFD2AEAB2 142B4E2B4403 1636862B33CF |
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37 | FFFF 1F23F079A304AD 1036032B1D6E 122AFD2AEBB1 142B4C2B4504 1636862B33CF |
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38 | |||
39 | Frame examples with no signal received |
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40 | |||
41 | FFFF 1F23F000A30426 |
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42 | FFFF 1F23F000A30426 |
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43 | FFFF 1F23F000A30426 |
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44 | FFFF 1F23F000A30426 |
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45 | FFFF 1F23F000A30426 |
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46 | FFFF 1F23F000A30426 |
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47 | FFFF 1F23F000A30426 |
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48 | */ |
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49 | |||
1200 | killagreg | 50 | uint8_t dsl_RSSI = 0; |
51 | uint8_t dsl_Battery = 0; |
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52 | uint8_t dsl_Allocation = 0; |
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53 | uint8_t PacketBuffer[6]; |
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1199 | killagreg | 54 | |
1200 | killagreg | 55 | typedef union |
56 | { |
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57 | int16_t Servo[2]; |
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58 | uint8_t byte[4]; |
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1206 | killagreg | 59 | } ChannelPair_t; |
1199 | killagreg | 60 | |
1206 | killagreg | 61 | ChannelPair_t ChannelPair; |
1199 | killagreg | 62 | |
1200 | killagreg | 63 | |
1199 | killagreg | 64 | // This function is called, when a new servo signal is properly received. |
65 | // Parameters: servo - servo number (0-9) |
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66 | // signal - servo signal between 7373 (1ms) and 14745 (2ms) |
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67 | void dsl_new_signal(uint8_t channel, int16_t signal) |
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68 | { |
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1200 | killagreg | 69 | int16_t tmp; |
70 | uint8_t index = channel + 1; // mk channels start with 1 |
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1199 | killagreg | 71 | |
72 | |||
1206 | killagreg | 73 | // signal from DSL-receiver is between 7373 (1ms) und 14745 (2ms). |
1200 | killagreg | 74 | signal-= 11059; // shift to neutral |
75 | signal/= 24; // scale to mk rc resolution |
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1199 | killagreg | 76 | |
1200 | killagreg | 77 | // calculate exponential history for signal |
78 | tmp = (3 * (PPM_in[index]) + signal) / 4; |
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79 | if(tmp > signal+1) tmp--; else |
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80 | if(tmp < signal-1) tmp++; |
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81 | // calculate signal difference on good signal level |
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82 | if(RC_Quality >= 195) PPM_diff[index] = ((tmp - PPM_in[index]) / 3) * 3; // cut off lower 3 bit for noise reduction |
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83 | else PPM_diff[index] = 0; |
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84 | PPM_in[index] = tmp; // update channel value |
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1199 | killagreg | 85 | |
1206 | killagreg | 86 | if(index == 4) |
87 | { |
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88 | NewPpmData = 0; |
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89 | NewRCFrames++; |
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90 | } |
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1199 | killagreg | 91 | } |
92 | |||
93 | // This function is called within dsl_parser(), when a complete |
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94 | // data packet with valid checksum has been received. |
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1200 | killagreg | 95 | void dsl_decode_packet(void) |
1199 | killagreg | 96 | { |
97 | uint8_t i; |
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98 | |||
1206 | killagreg | 99 | // check for header condition |
100 | if((PacketBuffer[0] & 0xF0) == 0x10) |
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101 | { |
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102 | if(PacketBuffer[0] == 0x1F) // separate status frame |
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1200 | killagreg | 103 | { |
1206 | killagreg | 104 | dsl_Allocation = PacketBuffer[1]; // Get frequency allocation |
105 | // ?? = PacketBuffer[2]; |
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106 | dsl_RSSI = PacketBuffer[3]; // Get signal quality |
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107 | RC_Quality = (212 * (uint16_t)dsl_RSSI) / 128; // have to be scaled approx. by a factor of 1.66 to get 200 at full level |
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108 | if(RC_Quality > 255) RC_Quality = 255; |
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109 | dsl_Battery = PacketBuffer[4]; // Get voltage of battery supply |
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110 | // ?? = PacketBuffer[5]; |
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111 | if(dsl_RSSI == 0) |
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112 | { |
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113 | for (i = 0; i<5; i++) |
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114 | { |
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115 | PPM_diff[i] = 0; |
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116 | PPM_in[i] = 0; |
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117 | } |
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118 | } |
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1200 | killagreg | 119 | } |
1206 | killagreg | 120 | else // probably a channel pair |
121 | { |
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122 | i = PacketBuffer[0] & 0x0F; // last 4 bits of the header indicates the channel pair |
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123 | if(i < 10)// maximum 12 channels |
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124 | { |
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125 | // big to little endian |
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126 | ChannelPair.byte[1] = PacketBuffer[1]; |
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127 | ChannelPair.byte[0] = PacketBuffer[2]; |
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128 | ChannelPair.byte[3] = PacketBuffer[3]; |
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129 | ChannelPair.byte[2] = PacketBuffer[4]; |
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130 | dsl_new_signal(i, ChannelPair.Servo[0]); |
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131 | dsl_new_signal(i+1,ChannelPair.Servo[1]); |
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132 | } |
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133 | } |
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134 | } // EOF header condition |
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1199 | killagreg | 135 | } |
136 | |||
137 | |||
138 | // this function should be called within the UART RX ISR |
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139 | void dsl_parser(uint8_t c) |
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140 | { |
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1206 | killagreg | 141 | static uint8_t last_c = 0; |
1199 | killagreg | 142 | static uint8_t crc = 0; |
1200 | killagreg | 143 | static uint8_t cnt = 0; |
144 | static uint8_t packet_len = 0; |
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1199 | killagreg | 145 | |
1206 | killagreg | 146 | // check for sync condition |
147 | if ((c==0xFF) && (last_c==0xFF)) |
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148 | { |
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149 | cnt = 0; // reset byte counter |
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150 | crc = 0; // reset checksum |
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151 | return; |
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152 | } |
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1199 | killagreg | 153 | |
1206 | killagreg | 154 | if(cnt == 0) // begin of a packet |
1199 | killagreg | 155 | { |
1206 | killagreg | 156 | if(c == 0x1F) packet_len = 5; // a status packet has 5 bytes + crc |
157 | else packet_len = 4; // a channel pair packet has 4 bytes + crc |
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1199 | killagreg | 158 | } |
1206 | killagreg | 159 | if(cnt > packet_len) // packet complete, crc byte received |
160 | { |
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161 | // calculate checksum |
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162 | crc = ~crc; |
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163 | if (crc == 0xFF) crc = 0xFE; |
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164 | // if crc matches decode the packet |
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165 | if (c == crc) dsl_decode_packet(); |
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166 | // handle next packet |
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167 | cnt = 0; |
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168 | crc = 0; |
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169 | } |
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170 | else // collect channel data bytes |
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171 | { |
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172 | PacketBuffer[cnt++] = c; |
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173 | crc += c; |
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174 | } |
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175 | // store last byte for sync check |
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176 | last_c = c; |
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1200 | killagreg | 177 | } |