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1207 | killagreg | 1 | // ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ |
2 | // This code has been derived from the implementation of Stefan Engelke. |
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3 | // ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ |
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4 | /* |
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5 | Copyright (c) 2008 Stefan Engelke <stefan@tinkerer.eu> |
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1199 | killagreg | 6 | |
1207 | killagreg | 7 | Permission is hereby granted, free of charge, to any person |
8 | obtaining a copy of this software and associated documentation |
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9 | files (the "Software"), to deal in the Software without |
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10 | restriction, including without limitation the rights to use, copy, |
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11 | modify, merge, publish, distribute, sublicense, and/or sell copies |
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12 | of the Software, and to permit persons to whom the Software is |
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13 | furnished to do so, subject to the following conditions: |
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14 | |||
15 | The above copyright notice and this permission notice shall be |
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16 | included in all copies or substantial portions of the Software. |
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17 | |||
18 | THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, |
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19 | EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF |
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20 | MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND |
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21 | NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT |
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22 | HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, |
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23 | WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
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24 | OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER |
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25 | DEALINGS IN THE SOFTWARE. |
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26 | |||
27 | $Id: rcdsl.c 60 2008-08-21 07:50:48Z taser $ |
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28 | |||
29 | RCDSL.H and RCDSL.C is an INOFFICIAL implementation of the |
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30 | communication protocol used by DSL receivers of Act Europe. |
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31 | The DSL receivers have a serial communication port to connect |
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32 | two receivers in diversity mode. Each receiver is sending the |
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33 | received servo signals periodically over this port. This fact |
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34 | can be used to connect the receiver to the control unit of the |
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35 | model via UART instead of evaluating the PPM signal. |
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36 | |||
37 | If you have any questions, fell free to send me an e-mail. |
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38 | |||
39 | */ |
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40 | |||
41 | |||
1199 | killagreg | 42 | /* |
1206 | killagreg | 43 | Connection of DSL to SV1 of FC: |
44 | ( DSL Pin1 is on side of channel 4 ) |
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1199 | killagreg | 45 | |
1206 | killagreg | 46 | 1. GND <--> pin 7 (GND) |
47 | 2. TXD <--> pin 3 (RXD1 Atmega644p) |
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48 | 3. RXD <--> pin 4 (TXD1 Atmega644p) optional |
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49 | 4. 5V <--> pin 2 (5V) |
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1199 | killagreg | 50 | |
1206 | killagreg | 51 | Do not connect the receiver via PPM-Sumsignal output the same time. |
1199 | killagreg | 52 | |
1207 | killagreg | 53 | Data are send at every 20 ms @ 38400 Baud 8-N-1 |
1199 | killagreg | 54 | |
1206 | killagreg | 55 | Data Frame: |0xFF|0xFF|0x1F|FREQALLOC|??|RSSI|VBAT|??|CRC|10|CH0D1|CH0D0|CH1D1|CH1D0|CRC| ...etc |
56 | |||
57 | FREQALLOC = 35, 40, 72 |
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58 | RSSI = 0.. 255 // Received signal strength indicator |
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1207 | killagreg | 59 | VBAT = 0...255 // supply voltage (0.0V.. 7.8V) |
1206 | killagreg | 60 | |
61 | Servo Pair: |0x1X|CHXD1|CHXD0|CHX+1D1|CHX+1D0|CRC| |
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62 | X is channel index of 1 servo value |
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63 | D1D0 is servo value as u16 in range of 7373 (1ms) to 14745 (2ms) |
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64 | there are 8 channels submitted, i.e 4 servo pairs |
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65 | |||
66 | |||
67 | Frame examples with signel received |
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68 | |||
69 | FFFF 1F23F079A304AD 1036012B1E6F 122AFB2AECB2 142B4D2B4404 1636872B33CE |
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70 | FFFF 1F23F079A304AD 1036002B1F6F 122AFE2AEBB0 142B4B2B4406 1636872B33CE |
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71 | FFFF 1F23F079A304AD 1035FF2B226E 122AFC2AEAB3 142B4E2B4304 1636882B33CD |
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72 | FFFF 1F23F079A304AD 1036022B1E6E 122AFB2AEEB0 142B4A2B4506 1636872B33CE |
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73 | FFFF 1F23F079A304AD 1036022B1E6E 122AFE2AEBB0 142B4B2B4406 1636882B33CD |
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74 | FFFF 1F23F079A304AD 1036012B1E6F 122AFD2AEAB2 142B4E2B4403 1636862B33CF |
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75 | FFFF 1F23F079A304AD 1036032B1D6E 122AFD2AEBB1 142B4C2B4504 1636862B33CF |
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76 | |||
77 | Frame examples with no signal received |
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78 | |||
79 | FFFF 1F23F000A30426 |
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80 | FFFF 1F23F000A30426 |
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81 | FFFF 1F23F000A30426 |
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82 | FFFF 1F23F000A30426 |
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83 | FFFF 1F23F000A30426 |
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84 | FFFF 1F23F000A30426 |
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85 | FFFF 1F23F000A30426 |
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86 | */ |
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87 | |||
1207 | killagreg | 88 | |
89 | #include "dsl.h" |
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90 | #include "rc.h" |
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1200 | killagreg | 91 | uint8_t dsl_RSSI = 0; |
92 | uint8_t dsl_Battery = 0; |
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93 | uint8_t dsl_Allocation = 0; |
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94 | uint8_t PacketBuffer[6]; |
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1199 | killagreg | 95 | |
1200 | killagreg | 96 | typedef union |
97 | { |
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98 | int16_t Servo[2]; |
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99 | uint8_t byte[4]; |
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1206 | killagreg | 100 | } ChannelPair_t; |
1199 | killagreg | 101 | |
1206 | killagreg | 102 | ChannelPair_t ChannelPair; |
1199 | killagreg | 103 | |
1200 | killagreg | 104 | |
1199 | killagreg | 105 | // This function is called, when a new servo signal is properly received. |
106 | // Parameters: servo - servo number (0-9) |
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107 | // signal - servo signal between 7373 (1ms) and 14745 (2ms) |
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108 | void dsl_new_signal(uint8_t channel, int16_t signal) |
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109 | { |
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1200 | killagreg | 110 | int16_t tmp; |
111 | uint8_t index = channel + 1; // mk channels start with 1 |
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1199 | killagreg | 112 | |
113 | |||
1206 | killagreg | 114 | // signal from DSL-receiver is between 7373 (1ms) und 14745 (2ms). |
1200 | killagreg | 115 | signal-= 11059; // shift to neutral |
116 | signal/= 24; // scale to mk rc resolution |
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1199 | killagreg | 117 | |
1200 | killagreg | 118 | // calculate exponential history for signal |
119 | tmp = (3 * (PPM_in[index]) + signal) / 4; |
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120 | if(tmp > signal+1) tmp--; else |
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121 | if(tmp < signal-1) tmp++; |
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122 | // calculate signal difference on good signal level |
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123 | 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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124 | else PPM_diff[index] = 0; |
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125 | PPM_in[index] = tmp; // update channel value |
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1199 | killagreg | 126 | |
1206 | killagreg | 127 | if(index == 4) |
128 | { |
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129 | NewPpmData = 0; |
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130 | NewRCFrames++; |
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131 | } |
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1199 | killagreg | 132 | } |
133 | |||
134 | // This function is called within dsl_parser(), when a complete |
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135 | // data packet with valid checksum has been received. |
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1200 | killagreg | 136 | void dsl_decode_packet(void) |
1199 | killagreg | 137 | { |
138 | uint8_t i; |
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139 | |||
1206 | killagreg | 140 | // check for header condition |
141 | if((PacketBuffer[0] & 0xF0) == 0x10) |
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142 | { |
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143 | if(PacketBuffer[0] == 0x1F) // separate status frame |
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1200 | killagreg | 144 | { |
1206 | killagreg | 145 | dsl_Allocation = PacketBuffer[1]; // Get frequency allocation |
146 | // ?? = PacketBuffer[2]; |
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147 | dsl_RSSI = PacketBuffer[3]; // Get signal quality |
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148 | 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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149 | if(RC_Quality > 255) RC_Quality = 255; |
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150 | dsl_Battery = PacketBuffer[4]; // Get voltage of battery supply |
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151 | // ?? = PacketBuffer[5]; |
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152 | if(dsl_RSSI == 0) |
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153 | { |
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154 | for (i = 0; i<5; i++) |
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155 | { |
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156 | PPM_diff[i] = 0; |
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157 | PPM_in[i] = 0; |
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158 | } |
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159 | } |
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1200 | killagreg | 160 | } |
1206 | killagreg | 161 | else // probably a channel pair |
162 | { |
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163 | i = PacketBuffer[0] & 0x0F; // last 4 bits of the header indicates the channel pair |
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164 | if(i < 10)// maximum 12 channels |
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165 | { |
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166 | // big to little endian |
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167 | ChannelPair.byte[1] = PacketBuffer[1]; |
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168 | ChannelPair.byte[0] = PacketBuffer[2]; |
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169 | ChannelPair.byte[3] = PacketBuffer[3]; |
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170 | ChannelPair.byte[2] = PacketBuffer[4]; |
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171 | dsl_new_signal(i, ChannelPair.Servo[0]); |
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172 | dsl_new_signal(i+1,ChannelPair.Servo[1]); |
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173 | } |
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174 | } |
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175 | } // EOF header condition |
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1199 | killagreg | 176 | } |
177 | |||
178 | |||
179 | // this function should be called within the UART RX ISR |
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180 | void dsl_parser(uint8_t c) |
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181 | { |
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1206 | killagreg | 182 | static uint8_t last_c = 0; |
1199 | killagreg | 183 | static uint8_t crc = 0; |
1200 | killagreg | 184 | static uint8_t cnt = 0; |
185 | static uint8_t packet_len = 0; |
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1199 | killagreg | 186 | |
1206 | killagreg | 187 | // check for sync condition |
188 | if ((c==0xFF) && (last_c==0xFF)) |
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189 | { |
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190 | cnt = 0; // reset byte counter |
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191 | crc = 0; // reset checksum |
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192 | return; |
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193 | } |
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1199 | killagreg | 194 | |
1206 | killagreg | 195 | if(cnt == 0) // begin of a packet |
1199 | killagreg | 196 | { |
1206 | killagreg | 197 | if(c == 0x1F) packet_len = 5; // a status packet has 5 bytes + crc |
198 | else packet_len = 4; // a channel pair packet has 4 bytes + crc |
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1199 | killagreg | 199 | } |
1206 | killagreg | 200 | if(cnt > packet_len) // packet complete, crc byte received |
201 | { |
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202 | // calculate checksum |
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203 | crc = ~crc; |
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204 | if (crc == 0xFF) crc = 0xFE; |
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205 | // if crc matches decode the packet |
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206 | if (c == crc) dsl_decode_packet(); |
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207 | // handle next packet |
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208 | cnt = 0; |
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209 | crc = 0; |
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210 | } |
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211 | else // collect channel data bytes |
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212 | { |
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213 | PacketBuffer[cnt++] = c; |
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214 | crc += c; |
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215 | } |
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216 | // store last byte for sync check |
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217 | last_c = c; |
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1200 | killagreg | 218 | } |