1 | /*
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2 | Copyright (c) 2013 Arduino LLC. All right reserved.
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3 |
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4 | This library is free software; you can redistribute it and/or
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5 | modify it under the terms of the GNU Lesser General Public
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6 | License as published by the Free Software Foundation; either
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7 | version 2.1 of the License, or (at your option) any later version.
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8 |
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9 | This library is distributed in the hope that it will be useful,
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10 | but WITHOUT ANY WARRANTY; without even the implied warranty of
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11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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12 | Lesser General Public License for more details.
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13 |
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14 | You should have received a copy of the GNU Lesser General Public
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15 | License along with this library; if not, write to the Free Software
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16 | Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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17 | */
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18 |
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19 | #include "Bridge.h"
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20 |
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21 | BridgeClass::BridgeClass(Stream &_stream) :
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22 | index(0), stream(_stream), started(false), max_retries(0) {
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23 | // Empty
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24 | }
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25 |
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26 | void BridgeClass::begin() {
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27 | if (started)
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28 | return;
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29 | started = true;
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30 |
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31 | // Wait for U-boot to finish startup
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32 | do {
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33 | dropAll();
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34 | delay(1000);
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35 | } while (stream.available() > 0);
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36 |
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37 | while (true) {
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38 | // Bridge interrupt:
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39 | // - Ask the bridge to close itself
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40 | uint8_t quit_cmd[] = {'X', 'X', 'X', 'X', 'X'};
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41 | max_retries = 1;
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42 | transfer(quit_cmd, 5);
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43 |
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44 | // Bridge startup:
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45 | // - If the bridge is not running starts it safely
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46 | stream.print(CTRL_C);
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47 | delay(250);
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48 | stream.print(F("\n"));
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49 | delay(250);
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50 | stream.print(F("\n"));
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51 | delay(500);
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52 | // Wait for OpenWRT message
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53 | // "Press enter to activate console"
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54 | stream.print(F("run-bridge\n"));
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55 | delay(500);
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56 | dropAll();
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57 |
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58 | // Reset the brigde to check if it is running
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59 | uint8_t cmd[] = {'X', 'X', '1', '0', '0'};
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60 | uint8_t res[4];
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61 | max_retries = 50;
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62 | uint16_t l = transfer(cmd, 5, res, 4);
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63 | if (l == TRANSFER_TIMEOUT) {
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64 | // Bridge didn't start...
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65 | // Maybe the board is starting-up?
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66 |
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67 | // Wait and retry
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68 | delay(1000);
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69 | continue;
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70 | }
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71 | if (res[0] != 0)
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72 | while (true);
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73 |
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74 | // Detect bridge version
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75 | if (l == 4) {
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76 | bridgeVersion = (res[1]-'0')*100 + (res[2]-'0')*10 + (res[3]-'0');
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77 | } else {
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78 | // Bridge v1.0.0 didn't send any version info
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79 | bridgeVersion = 100;
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80 | }
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81 |
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82 | max_retries = 50;
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83 | return;
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84 | }
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85 | }
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86 |
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87 | void BridgeClass::put(const char *key, const char *value) {
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88 | // TODO: do it in a more efficient way
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89 | String cmd = "D";
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90 | cmd += key;
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91 | cmd += "\xFE";
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92 | cmd += value;
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93 | transfer((uint8_t*)cmd.c_str(), cmd.length());
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94 | }
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95 |
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96 | unsigned int BridgeClass::get(const char *key, uint8_t *value, unsigned int maxlen) {
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97 | uint8_t cmd[] = {'d'};
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98 | unsigned int l = transfer(cmd, 1, (uint8_t *)key, strlen(key), value, maxlen);
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99 | if (l < maxlen)
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100 | value[l] = 0; // Zero-terminate string
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101 | return l;
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102 | }
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103 |
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104 | #if defined(ARDUINO_ARCH_AVR)
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105 | // AVR use an optimized implementation of CRC
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106 | #include <util/crc16.h>
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107 | #else
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108 | // Generic implementation for non-AVR architectures
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109 | uint16_t _crc_ccitt_update(uint16_t crc, uint8_t data)
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110 | {
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111 | data ^= crc & 0xff;
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112 | data ^= data << 4;
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113 | return ((((uint16_t)data << 8) | ((crc >> 8) & 0xff)) ^
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114 | (uint8_t)(data >> 4) ^
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115 | ((uint16_t)data << 3));
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116 | }
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117 | #endif
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118 |
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119 | void BridgeClass::crcUpdate(uint8_t c) {
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120 | CRC = _crc_ccitt_update(CRC, c);
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121 | }
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122 |
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123 | void BridgeClass::crcReset() {
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124 | CRC = 0xFFFF;
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125 | }
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126 |
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127 | void BridgeClass::crcWrite() {
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128 | stream.write((char)(CRC >> 8));
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129 | stream.write((char)(CRC & 0xFF));
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130 | }
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131 |
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132 | bool BridgeClass::crcCheck(uint16_t _CRC) {
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133 | return CRC == _CRC;
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134 | }
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135 |
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136 | uint16_t BridgeClass::transfer(const uint8_t *buff1, uint16_t len1,
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137 | const uint8_t *buff2, uint16_t len2,
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138 | const uint8_t *buff3, uint16_t len3,
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139 | uint8_t *rxbuff, uint16_t rxlen)
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140 | {
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141 | uint16_t len = len1 + len2 + len3;
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142 | uint8_t retries = 0;
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143 | for ( ; retries < max_retries; retries++, delay(100), dropAll() /* Delay for retransmission */) {
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144 | // Send packet
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145 | crcReset();
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146 | stream.write((char)0xFF); // Start of packet (0xFF)
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147 | crcUpdate(0xFF);
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148 | stream.write((char)index); // Message index
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149 | crcUpdate(index);
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150 | stream.write((char)((len >> 8) & 0xFF)); // Message length (hi)
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151 | crcUpdate((len >> 8) & 0xFF);
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152 | stream.write((char)(len & 0xFF)); // Message length (lo)
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153 | crcUpdate(len & 0xFF);
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154 | for (uint16_t i = 0; i < len1; i++) { // Payload
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155 | stream.write((char)buff1[i]);
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156 | crcUpdate(buff1[i]);
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157 | }
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158 | for (uint16_t i = 0; i < len2; i++) { // Payload
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159 | stream.write((char)buff2[i]);
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160 | crcUpdate(buff2[i]);
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161 | }
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162 | for (uint16_t i = 0; i < len3; i++) { // Payload
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163 | stream.write((char)buff3[i]);
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164 | crcUpdate(buff3[i]);
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165 | }
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166 | crcWrite(); // CRC
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167 |
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168 | // Wait for ACK in 100ms
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169 | if (timedRead(100) != 0xFF)
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170 | continue;
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171 | crcReset();
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172 | crcUpdate(0xFF);
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173 |
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174 | // Check packet index
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175 | if (timedRead(5) != index)
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176 | continue;
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177 | crcUpdate(index);
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178 |
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179 | // Recv len
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180 | int lh = timedRead(10);
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181 | if (lh < 0)
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182 | continue;
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183 | crcUpdate(lh);
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184 | int ll = timedRead(10);
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185 | if (ll < 0)
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186 | continue;
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187 | crcUpdate(ll);
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188 | uint16_t l = lh;
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189 | l <<= 8;
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190 | l += ll;
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191 |
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192 | // Recv data
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193 | for (uint16_t i = 0; i < l; i++) {
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194 | int c = timedRead(5);
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195 | if (c < 0)
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196 | continue;
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197 | // Cut received data if rxbuffer is too small
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198 | if (i < rxlen)
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199 | rxbuff[i] = c;
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200 | crcUpdate(c);
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201 | }
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202 |
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203 | // Check CRC
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204 | int crc_hi = timedRead(5);
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205 | if (crc_hi < 0)
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206 | continue;
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207 | int crc_lo = timedRead(5);
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208 | if (crc_lo < 0)
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209 | continue;
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210 | if (!crcCheck((crc_hi << 8) + crc_lo))
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211 | continue;
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212 |
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213 | // Increase index
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214 | index++;
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215 |
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216 | // Return bytes received
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217 | if (l > rxlen)
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218 | return rxlen;
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219 | return l;
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220 | }
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221 |
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222 | // Max retries exceeded
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223 | return TRANSFER_TIMEOUT;
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224 | }
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225 |
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226 | int BridgeClass::timedRead(unsigned int timeout) {
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227 | int c;
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228 | unsigned long _startMillis = millis();
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229 | do {
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230 | c = stream.read();
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231 | if (c >= 0) return c;
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232 | } while (millis() - _startMillis < timeout);
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233 | return -1; // -1 indicates timeout
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234 | }
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235 |
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236 | void BridgeClass::dropAll() {
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237 | while (stream.available() > 0) {
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238 | stream.read();
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239 | }
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240 | }
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241 |
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242 | // Bridge instance
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243 | #ifdef __AVR_ATmega32U4__
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244 | // Leonardo variants (where HardwareSerial is Serial1)
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245 | SerialBridgeClass Bridge(Serial1);
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246 | #else
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247 | SerialBridgeClass Bridge(Serial);
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248 | #endif
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