Manchester
Manchester.cpp@5:3b2c7e9fda3f, 2017-05-21 (annotated)
- Committer:
- hudakz
- Date:
- Sun May 21 19:17:28 2017 +0000
- Revision:
- 5:3b2c7e9fda3f
- Parent:
- 4:f2c392191c74
- Child:
- 6:7454ad91f714
Added IEEE 802.3 convention.
Who changed what in which revision?
User | Revision | Line number | New contents of line |
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hudakz | 0:d5c75b0e5708 | 1 | /* |
hudakz | 0:d5c75b0e5708 | 2 | ****************************************************************************** |
hudakz | 0:d5c75b0e5708 | 3 | * @file Manchester.cpp |
hudakz | 0:d5c75b0e5708 | 4 | * @author Zoltan Hudak |
hudakz | 2:de778df5892c | 5 | * @version |
hudakz | 0:d5c75b0e5708 | 6 | * @date 16-May-2017 |
hudakz | 0:d5c75b0e5708 | 7 | * @brief Manchester code for mbed |
hudakz | 0:d5c75b0e5708 | 8 | ****************************************************************************** |
hudakz | 0:d5c75b0e5708 | 9 | * @attention |
hudakz | 0:d5c75b0e5708 | 10 | * |
hudakz | 0:d5c75b0e5708 | 11 | * <h2><center>© COPYRIGHT(c) 2017 Zoltan Hudak <hudakz@outlook.com> |
hudakz | 0:d5c75b0e5708 | 12 | * |
hudakz | 0:d5c75b0e5708 | 13 | * All rights reserved. |
hudakz | 0:d5c75b0e5708 | 14 | |
hudakz | 0:d5c75b0e5708 | 15 | This program is free software: you can redistribute it and/or modify |
hudakz | 0:d5c75b0e5708 | 16 | it under the terms of the GNU General Public License as published by |
hudakz | 0:d5c75b0e5708 | 17 | the Free Software Foundation, either version 3 of the License, or |
hudakz | 0:d5c75b0e5708 | 18 | (at your option) any later version. |
hudakz | 0:d5c75b0e5708 | 19 | |
hudakz | 0:d5c75b0e5708 | 20 | This program is distributed in the hope that it will be useful, |
hudakz | 0:d5c75b0e5708 | 21 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
hudakz | 0:d5c75b0e5708 | 22 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
hudakz | 0:d5c75b0e5708 | 23 | GNU General Public License for more details. |
hudakz | 0:d5c75b0e5708 | 24 | |
hudakz | 0:d5c75b0e5708 | 25 | You should have received a copy of the GNU General Public License |
hudakz | 0:d5c75b0e5708 | 26 | along with this program. If not, see <http://www.gnu.org/licenses/>. |
hudakz | 0:d5c75b0e5708 | 27 | */ |
hudakz | 5:3b2c7e9fda3f | 28 | |
hudakz | 5:3b2c7e9fda3f | 29 | /* |
hudakz | 5:3b2c7e9fda3f | 30 | This library implements Manchester code according to both IEEE 802.3 |
hudakz | 5:3b2c7e9fda3f | 31 | and G.E. Thomas' convention. |
hudakz | 5:3b2c7e9fda3f | 32 | • A '0' is expressed by a high-to-low transition, a '1' by low-to-high transition |
hudakz | 5:3b2c7e9fda3f | 33 | in the IEEE 802.3 convention. The reverse is true in the G.E. Thomas' convention. |
hudakz | 5:3b2c7e9fda3f | 34 | • The transitions which signify 0 or 1 occur at the midpoint of a period. |
hudakz | 5:3b2c7e9fda3f | 35 | • Transitions at the start of a period are overhead and don't signify data. |
hudakz | 5:3b2c7e9fda3f | 36 | • Least significant bit is sent first |
hudakz | 5:3b2c7e9fda3f | 37 | • There is one synchronization pulse at the begin of transmission |
hudakz | 5:3b2c7e9fda3f | 38 | |
hudakz | 5:3b2c7e9fda3f | 39 | The IEEE 802.3 convention is used by default. |
hudakz | 5:3b2c7e9fda3f | 40 | Select a convention to be used by commenting or uncommenting |
hudakz | 5:3b2c7e9fda3f | 41 | the line "#define G_E_THOMAS 1" in the Manchester.h header file. |
hudakz | 5:3b2c7e9fda3f | 42 | */ |
hudakz | 5:3b2c7e9fda3f | 43 | |
hudakz | 0:d5c75b0e5708 | 44 | #include "Manchester.h" |
hudakz | 0:d5c75b0e5708 | 45 | #include "ManchesterMsg.h" |
hudakz | 0:d5c75b0e5708 | 46 | |
hudakz | 0:d5c75b0e5708 | 47 | /** |
hudakz | 0:d5c75b0e5708 | 48 | * @brief Creates a Manchester object |
hudakz | 0:d5c75b0e5708 | 49 | * @note |
hudakz | 0:d5c75b0e5708 | 50 | * @param txPin Pin name of transmitter line |
hudakz | 0:d5c75b0e5708 | 51 | * rxPin Pin name of receiver line |
hudakz | 0:d5c75b0e5708 | 52 | * speed Communication bit rate in bits per second |
hudakz | 3:03109c995123 | 53 | * tol Pulse width tolerance in % |
hudakz | 0:d5c75b0e5708 | 54 | * @retval |
hudakz | 0:d5c75b0e5708 | 55 | */ |
hudakz | 3:03109c995123 | 56 | Manchester::Manchester |
hudakz | 3:03109c995123 | 57 | ( |
hudakz | 3:03109c995123 | 58 | PinName txPin, |
hudakz | 3:03109c995123 | 59 | PinName rxPin, |
hudakz | 5:3b2c7e9fda3f | 60 | uint32_t speed, /* = 1200 bps */ |
hudakz | 5:3b2c7e9fda3f | 61 | uint8_t tol /* = (+/-)25% */ |
hudakz | 3:03109c995123 | 62 | ) : |
hudakz | 3:03109c995123 | 63 | _tx(txPin), |
hudakz | 2:de778df5892c | 64 | _rx(rxPin) { |
hudakz | 0:d5c75b0e5708 | 65 | _state = IDLE; |
hudakz | 0:d5c75b0e5708 | 66 | _midBitTime = 1000000 / speed / 2; // mid-bit time [us] |
hudakz | 0:d5c75b0e5708 | 67 | _minPulseWidth = (_midBitTime * 2 * (100 - tol)) / 100; // [us] |
hudakz | 0:d5c75b0e5708 | 68 | _maxPulseWidth = (_midBitTime * 2 * (100 + tol)) / 100; // [us] |
hudakz | 0:d5c75b0e5708 | 69 | _rx.disable_irq(); |
hudakz | 0:d5c75b0e5708 | 70 | _rx.rise(callback(this, &Manchester::reception)); |
hudakz | 0:d5c75b0e5708 | 71 | _rx.fall(callback(this, &Manchester::reception)); |
hudakz | 5:3b2c7e9fda3f | 72 | #ifdef G_E_THOMAS |
hudakz | 5:3b2c7e9fda3f | 73 | _tx = 1; |
hudakz | 5:3b2c7e9fda3f | 74 | #else |
hudakz | 5:3b2c7e9fda3f | 75 | _tx = 0; |
hudakz | 5:3b2c7e9fda3f | 76 | #endif |
hudakz | 0:d5c75b0e5708 | 77 | } |
hudakz | 0:d5c75b0e5708 | 78 | |
hudakz | 0:d5c75b0e5708 | 79 | /** |
hudakz | 0:d5c75b0e5708 | 80 | * @brief Transmits message |
hudakz | 0:d5c75b0e5708 | 81 | * @note |
hudakz | 0:d5c75b0e5708 | 82 | * @param msg Message to transmit |
hudakz | 0:d5c75b0e5708 | 83 | * @retval |
hudakz | 0:d5c75b0e5708 | 84 | */ |
hudakz | 0:d5c75b0e5708 | 85 | void Manchester::transmit(ManchesterMsg& msg) { |
hudakz | 0:d5c75b0e5708 | 86 | bool txComplete; |
hudakz | 0:d5c75b0e5708 | 87 | |
hudakz | 0:d5c75b0e5708 | 88 | _data = msg.data; |
hudakz | 0:d5c75b0e5708 | 89 | _len = msg.len; |
hudakz | 0:d5c75b0e5708 | 90 | _state = SYNCH_START; |
hudakz | 0:d5c75b0e5708 | 91 | _txTicker.attach_us(callback(this, &Manchester::transmission), _midBitTime); |
hudakz | 0:d5c75b0e5708 | 92 | |
hudakz | 0:d5c75b0e5708 | 93 | do |
hudakz | 0:d5c75b0e5708 | 94 | { |
hudakz | 0:d5c75b0e5708 | 95 | core_util_critical_section_enter(); |
hudakz | 0:d5c75b0e5708 | 96 | txComplete = (_state == IDLE); |
hudakz | 0:d5c75b0e5708 | 97 | core_util_critical_section_exit(); |
hudakz | 0:d5c75b0e5708 | 98 | } while(!txComplete); |
hudakz | 0:d5c75b0e5708 | 99 | |
hudakz | 0:d5c75b0e5708 | 100 | _txTicker.detach(); |
hudakz | 0:d5c75b0e5708 | 101 | } |
hudakz | 0:d5c75b0e5708 | 102 | |
hudakz | 0:d5c75b0e5708 | 103 | /** |
hudakz | 0:d5c75b0e5708 | 104 | * @brief ISR handling transmission |
hudakz | 3:03109c995123 | 105 | * @note Called by _txTicker |
hudakz | 0:d5c75b0e5708 | 106 | * @param |
hudakz | 0:d5c75b0e5708 | 107 | * @retval |
hudakz | 0:d5c75b0e5708 | 108 | */ |
hudakz | 0:d5c75b0e5708 | 109 | void Manchester::transmission(void) { |
hudakz | 0:d5c75b0e5708 | 110 | static uint8_t encodeByte; |
hudakz | 2:de778df5892c | 111 | static size_t byteIndex; |
hudakz | 0:d5c75b0e5708 | 112 | static uint8_t bitIndex; |
hudakz | 0:d5c75b0e5708 | 113 | |
hudakz | 2:de778df5892c | 114 | _timeout.attach_us(callback(this, &Manchester::txTimeout), _maxPulseWidth * 4); |
hudakz | 2:de778df5892c | 115 | |
hudakz | 0:d5c75b0e5708 | 116 | switch(_state) { |
hudakz | 0:d5c75b0e5708 | 117 | case SYNCH_START: |
hudakz | 5:3b2c7e9fda3f | 118 | #ifdef G_E_THOMAS |
hudakz | 5:3b2c7e9fda3f | 119 | _tx = 0; // pull line low to start synch pulse |
hudakz | 5:3b2c7e9fda3f | 120 | #else |
hudakz | 5:3b2c7e9fda3f | 121 | _tx = 1; // bring line high to start synch pulse |
hudakz | 5:3b2c7e9fda3f | 122 | #endif |
hudakz | 0:d5c75b0e5708 | 123 | _state = SYNCH_NEXT; |
hudakz | 0:d5c75b0e5708 | 124 | break; |
hudakz | 0:d5c75b0e5708 | 125 | |
hudakz | 0:d5c75b0e5708 | 126 | case SYNCH_NEXT: |
hudakz | 0:d5c75b0e5708 | 127 | _state = SYNCH_END; // synch pulse needs to be twice the interrupt rate |
hudakz | 0:d5c75b0e5708 | 128 | break; |
hudakz | 0:d5c75b0e5708 | 129 | |
hudakz | 0:d5c75b0e5708 | 130 | case SYNCH_END: |
hudakz | 5:3b2c7e9fda3f | 131 | #ifdef G_E_THOMAS |
hudakz | 2:de778df5892c | 132 | _tx = 1; // bring line high for end of sych pulse |
hudakz | 5:3b2c7e9fda3f | 133 | #else |
hudakz | 5:3b2c7e9fda3f | 134 | _tx = 0; // pull line low for end of sych pulse |
hudakz | 5:3b2c7e9fda3f | 135 | #endif |
hudakz | 0:d5c75b0e5708 | 136 | byteIndex = 0; |
hudakz | 0:d5c75b0e5708 | 137 | encodeByte = _data[byteIndex]; |
hudakz | 0:d5c75b0e5708 | 138 | bitIndex = 0; |
hudakz | 0:d5c75b0e5708 | 139 | _state = SETUP; |
hudakz | 0:d5c75b0e5708 | 140 | break; |
hudakz | 0:d5c75b0e5708 | 141 | |
hudakz | 0:d5c75b0e5708 | 142 | case SETUP: |
hudakz | 5:3b2c7e9fda3f | 143 | #ifdef G_E_THOMAS |
hudakz | 5:3b2c7e9fda3f | 144 | _tx = encodeByte & 0x01; // setup for next bit to transmit |
hudakz | 5:3b2c7e9fda3f | 145 | #else |
hudakz | 5:3b2c7e9fda3f | 146 | _tx = !(encodeByte & 0x01); // setup for next bit to transmit |
hudakz | 5:3b2c7e9fda3f | 147 | #endif |
hudakz | 0:d5c75b0e5708 | 148 | _state = TRANSITION; |
hudakz | 0:d5c75b0e5708 | 149 | break; |
hudakz | 0:d5c75b0e5708 | 150 | |
hudakz | 0:d5c75b0e5708 | 151 | case TRANSITION: |
hudakz | 5:3b2c7e9fda3f | 152 | #ifdef G_E_THOMAS |
hudakz | 5:3b2c7e9fda3f | 153 | _tx = !(encodeByte & 0x01); // set line appropriately for transition |
hudakz | 5:3b2c7e9fda3f | 154 | #else |
hudakz | 5:3b2c7e9fda3f | 155 | _tx = encodeByte & 0x01; // set line appropriately for transition |
hudakz | 5:3b2c7e9fda3f | 156 | #endif |
hudakz | 0:d5c75b0e5708 | 157 | if(++bitIndex < 8) { |
hudakz | 0:d5c75b0e5708 | 158 | encodeByte = (encodeByte >> 1); |
hudakz | 0:d5c75b0e5708 | 159 | _state = SETUP; |
hudakz | 0:d5c75b0e5708 | 160 | } |
hudakz | 0:d5c75b0e5708 | 161 | else { |
hudakz | 0:d5c75b0e5708 | 162 | if(++byteIndex < _len) { |
hudakz | 0:d5c75b0e5708 | 163 | encodeByte = _data[byteIndex]; |
hudakz | 0:d5c75b0e5708 | 164 | _state = SETUP; |
hudakz | 0:d5c75b0e5708 | 165 | bitIndex = 0; |
hudakz | 0:d5c75b0e5708 | 166 | } |
hudakz | 0:d5c75b0e5708 | 167 | else |
hudakz | 0:d5c75b0e5708 | 168 | _state = COMPLETE; |
hudakz | 0:d5c75b0e5708 | 169 | } |
hudakz | 0:d5c75b0e5708 | 170 | break; |
hudakz | 0:d5c75b0e5708 | 171 | |
hudakz | 0:d5c75b0e5708 | 172 | case COMPLETE: |
hudakz | 5:3b2c7e9fda3f | 173 | #ifdef G_E_THOMAS |
hudakz | 2:de778df5892c | 174 | _tx = 1; // transmission is complete, bring line high |
hudakz | 5:3b2c7e9fda3f | 175 | #else |
hudakz | 5:3b2c7e9fda3f | 176 | _tx = 0; // transmission is complete, pull line low |
hudakz | 5:3b2c7e9fda3f | 177 | #endif |
hudakz | 0:d5c75b0e5708 | 178 | _state = IDLE; |
hudakz | 0:d5c75b0e5708 | 179 | break; |
hudakz | 0:d5c75b0e5708 | 180 | |
hudakz | 0:d5c75b0e5708 | 181 | case IDLE: |
hudakz | 0:d5c75b0e5708 | 182 | default: |
hudakz | 2:de778df5892c | 183 | _timeout.detach(); |
hudakz | 0:d5c75b0e5708 | 184 | return; |
hudakz | 0:d5c75b0e5708 | 185 | } |
hudakz | 0:d5c75b0e5708 | 186 | } |
hudakz | 0:d5c75b0e5708 | 187 | |
hudakz | 0:d5c75b0e5708 | 188 | /** |
hudakz | 2:de778df5892c | 189 | * @brief ISR handling 'transmission timeout' |
hudakz | 2:de778df5892c | 190 | * @note Called when transmitter is stuck. |
hudakz | 2:de778df5892c | 191 | * Signals 'end of transmission' by setting state to IDLE |
hudakz | 5:3b2c7e9fda3f | 192 | * @param |
hudakz | 5:3b2c7e9fda3f | 193 | * @retval |
hudakz | 2:de778df5892c | 194 | */ |
hudakz | 2:de778df5892c | 195 | void Manchester::txTimeout(void) { |
hudakz | 2:de778df5892c | 196 | _timeout.detach(); |
hudakz | 2:de778df5892c | 197 | _state = IDLE; |
hudakz | 2:de778df5892c | 198 | } |
hudakz | 2:de778df5892c | 199 | |
hudakz | 2:de778df5892c | 200 | /** |
hudakz | 0:d5c75b0e5708 | 201 | * @brief Receives message |
hudakz | 4:f2c392191c74 | 202 | * @note Waits until a message is received or 'receive timeout' occured |
hudakz | 1:11292d238e50 | 203 | * @param msg Container to store the received message |
hudakz | 0:d5c75b0e5708 | 204 | * @retval true On success |
hudakz | 0:d5c75b0e5708 | 205 | * false Otherwise |
hudakz | 0:d5c75b0e5708 | 206 | */ |
hudakz | 0:d5c75b0e5708 | 207 | bool Manchester::receive(ManchesterMsg& msg) { |
hudakz | 0:d5c75b0e5708 | 208 | bool rxFinished; |
hudakz | 0:d5c75b0e5708 | 209 | uint32_t now = us_ticker_read(); |
hudakz | 0:d5c75b0e5708 | 210 | |
hudakz | 0:d5c75b0e5708 | 211 | _data = msg.data; |
hudakz | 0:d5c75b0e5708 | 212 | _maxLen = msg.maxLen(); |
hudakz | 0:d5c75b0e5708 | 213 | _state = LISTEN; |
hudakz | 0:d5c75b0e5708 | 214 | |
hudakz | 0:d5c75b0e5708 | 215 | core_util_critical_section_enter(); |
hudakz | 0:d5c75b0e5708 | 216 | _rx.enable_irq(); |
hudakz | 0:d5c75b0e5708 | 217 | core_util_critical_section_exit(); |
hudakz | 0:d5c75b0e5708 | 218 | |
hudakz | 0:d5c75b0e5708 | 219 | do |
hudakz | 0:d5c75b0e5708 | 220 | { |
hudakz | 0:d5c75b0e5708 | 221 | core_util_critical_section_enter(); |
hudakz | 0:d5c75b0e5708 | 222 | rxFinished = ((_state == IDLE) || (_state == ERROR)); |
hudakz | 0:d5c75b0e5708 | 223 | core_util_critical_section_exit(); |
hudakz | 0:d5c75b0e5708 | 224 | } while(!rxFinished); |
hudakz | 0:d5c75b0e5708 | 225 | |
hudakz | 0:d5c75b0e5708 | 226 | core_util_critical_section_enter(); |
hudakz | 0:d5c75b0e5708 | 227 | _rx.disable_irq(); |
hudakz | 0:d5c75b0e5708 | 228 | core_util_critical_section_exit(); |
hudakz | 0:d5c75b0e5708 | 229 | |
hudakz | 0:d5c75b0e5708 | 230 | if(_state == ERROR) { |
hudakz | 0:d5c75b0e5708 | 231 | msg.len = 0; |
hudakz | 0:d5c75b0e5708 | 232 | _state = IDLE; |
hudakz | 0:d5c75b0e5708 | 233 | return false; |
hudakz | 0:d5c75b0e5708 | 234 | } |
hudakz | 0:d5c75b0e5708 | 235 | else { |
hudakz | 0:d5c75b0e5708 | 236 | msg.len = _len; |
hudakz | 0:d5c75b0e5708 | 237 | return true; |
hudakz | 0:d5c75b0e5708 | 238 | } |
hudakz | 0:d5c75b0e5708 | 239 | } |
hudakz | 0:d5c75b0e5708 | 240 | |
hudakz | 0:d5c75b0e5708 | 241 | /** |
hudakz | 2:de778df5892c | 242 | * @brief ISR handling reception |
hudakz | 2:de778df5892c | 243 | * @note Called on signal change (rise or fall) on receiver line |
hudakz | 0:d5c75b0e5708 | 244 | * @param |
hudakz | 0:d5c75b0e5708 | 245 | * @retval |
hudakz | 0:d5c75b0e5708 | 246 | */ |
hudakz | 0:d5c75b0e5708 | 247 | void Manchester::reception(void) { |
hudakz | 0:d5c75b0e5708 | 248 | uint32_t now = us_ticker_read(); |
hudakz | 0:d5c75b0e5708 | 249 | static uint32_t begin; |
hudakz | 0:d5c75b0e5708 | 250 | uint32_t pulseWidth; |
hudakz | 0:d5c75b0e5708 | 251 | static uint8_t decodeByte; |
hudakz | 0:d5c75b0e5708 | 252 | static uint8_t bitIndex; |
hudakz | 0:d5c75b0e5708 | 253 | |
hudakz | 2:de778df5892c | 254 | _timeout.attach_us(callback(this, &Manchester::rxTimeout), _maxPulseWidth * 4); |
hudakz | 2:de778df5892c | 255 | |
hudakz | 0:d5c75b0e5708 | 256 | switch(_state) { |
hudakz | 0:d5c75b0e5708 | 257 | case LISTEN: |
hudakz | 0:d5c75b0e5708 | 258 | begin = now; |
hudakz | 5:3b2c7e9fda3f | 259 | #ifdef G_E_THOMAS |
hudakz | 2:de778df5892c | 260 | if(_rx == 0) |
hudakz | 5:3b2c7e9fda3f | 261 | #else |
hudakz | 5:3b2c7e9fda3f | 262 | if(_rx == 1) |
hudakz | 5:3b2c7e9fda3f | 263 | #endif |
hudakz | 0:d5c75b0e5708 | 264 | _state = SYNCH_START; |
hudakz | 0:d5c75b0e5708 | 265 | else |
hudakz | 3:03109c995123 | 266 | _state = ERROR; // It isn't a synch pulse => error |
hudakz | 0:d5c75b0e5708 | 267 | break; |
hudakz | 0:d5c75b0e5708 | 268 | |
hudakz | 0:d5c75b0e5708 | 269 | case SYNCH_START: |
hudakz | 0:d5c75b0e5708 | 270 | pulseWidth = now - begin; |
hudakz | 5:3b2c7e9fda3f | 271 | #ifdef G_E_THOMAS |
hudakz | 2:de778df5892c | 272 | if((_minPulseWidth <= pulseWidth) && (pulseWidth <= _maxPulseWidth) && (_rx == 1)) { |
hudakz | 5:3b2c7e9fda3f | 273 | #else |
hudakz | 5:3b2c7e9fda3f | 274 | if((_minPulseWidth <= pulseWidth) && (pulseWidth <= _maxPulseWidth) && (_rx == 0)) { |
hudakz | 5:3b2c7e9fda3f | 275 | #endif |
hudakz | 0:d5c75b0e5708 | 276 | begin = now; |
hudakz | 0:d5c75b0e5708 | 277 | decodeByte = 0; |
hudakz | 2:de778df5892c | 278 | bitIndex = 0; |
hudakz | 0:d5c75b0e5708 | 279 | _len = 0; |
hudakz | 0:d5c75b0e5708 | 280 | _state = DECODE; |
hudakz | 0:d5c75b0e5708 | 281 | } |
hudakz | 2:de778df5892c | 282 | else |
hudakz | 2:de778df5892c | 283 | _state = ERROR; // It isn't a synch pulse => error |
hudakz | 0:d5c75b0e5708 | 284 | break; |
hudakz | 0:d5c75b0e5708 | 285 | |
hudakz | 0:d5c75b0e5708 | 286 | case DECODE: |
hudakz | 0:d5c75b0e5708 | 287 | pulseWidth = now - begin; |
hudakz | 0:d5c75b0e5708 | 288 | if((_minPulseWidth <= pulseWidth) && (pulseWidth <= _maxPulseWidth)) { |
hudakz | 0:d5c75b0e5708 | 289 | begin = now; |
hudakz | 5:3b2c7e9fda3f | 290 | #ifdef G_E_THOMAS |
hudakz | 0:d5c75b0e5708 | 291 | decodeByte |= (((_rx == 0) & 0x01) << bitIndex++); |
hudakz | 5:3b2c7e9fda3f | 292 | #else |
hudakz | 5:3b2c7e9fda3f | 293 | decodeByte |= (((_rx == 1) & 0x01) << bitIndex++); |
hudakz | 5:3b2c7e9fda3f | 294 | #endif |
hudakz | 0:d5c75b0e5708 | 295 | if(bitIndex > 7) { |
hudakz | 0:d5c75b0e5708 | 296 | _data[_len++] = decodeByte; |
hudakz | 0:d5c75b0e5708 | 297 | if(_len > _maxLen - 1) |
hudakz | 0:d5c75b0e5708 | 298 | _state = ERROR; |
hudakz | 0:d5c75b0e5708 | 299 | else { |
hudakz | 0:d5c75b0e5708 | 300 | decodeByte = 0; |
hudakz | 0:d5c75b0e5708 | 301 | bitIndex = 0; |
hudakz | 0:d5c75b0e5708 | 302 | } |
hudakz | 0:d5c75b0e5708 | 303 | } |
hudakz | 0:d5c75b0e5708 | 304 | } |
hudakz | 0:d5c75b0e5708 | 305 | |
hudakz | 2:de778df5892c | 306 | if(pulseWidth > _maxPulseWidth) |
hudakz | 2:de778df5892c | 307 | _state = ERROR; // Pulse width out of limit => error |
hudakz | 0:d5c75b0e5708 | 308 | |
hudakz | 0:d5c75b0e5708 | 309 | break; |
hudakz | 0:d5c75b0e5708 | 310 | |
hudakz | 0:d5c75b0e5708 | 311 | case IDLE: |
hudakz | 0:d5c75b0e5708 | 312 | case ERROR: |
hudakz | 0:d5c75b0e5708 | 313 | default: |
hudakz | 2:de778df5892c | 314 | _timeout.detach(); |
hudakz | 0:d5c75b0e5708 | 315 | break; |
hudakz | 0:d5c75b0e5708 | 316 | } |
hudakz | 0:d5c75b0e5708 | 317 | } |
hudakz | 0:d5c75b0e5708 | 318 | |
hudakz | 0:d5c75b0e5708 | 319 | /** |
hudakz | 2:de778df5892c | 320 | * @brief ISR handling 'receive timeout' |
hudakz | 3:03109c995123 | 321 | * @note Called when receiver line is idle longer than limit. |
hudakz | 2:de778df5892c | 322 | * Signals 'end of transmission' by setting state to IDLE |
hudakz | 2:de778df5892c | 323 | * or 'timeout error' by setting state to ERROR. |
hudakz | 5:3b2c7e9fda3f | 324 | * @param |
hudakz | 5:3b2c7e9fda3f | 325 | * @retval |
hudakz | 0:d5c75b0e5708 | 326 | */ |
hudakz | 0:d5c75b0e5708 | 327 | void Manchester::rxTimeout(void) { |
hudakz | 2:de778df5892c | 328 | _timeout.detach(); |
hudakz | 0:d5c75b0e5708 | 329 | |
hudakz | 5:3b2c7e9fda3f | 330 | #ifdef G_E_THOMAS |
hudakz | 2:de778df5892c | 331 | if((_state == DECODE) && (_rx == 1)) |
hudakz | 5:3b2c7e9fda3f | 332 | #else |
hudakz | 5:3b2c7e9fda3f | 333 | if((_state == DECODE) && (_rx == 0)) |
hudakz | 5:3b2c7e9fda3f | 334 | #endif |
hudakz | 0:d5c75b0e5708 | 335 | _state = IDLE; // End of transmission |
hudakz | 0:d5c75b0e5708 | 336 | else |
hudakz | 0:d5c75b0e5708 | 337 | _state = ERROR; // Incomplete transmission |
hudakz | 0:d5c75b0e5708 | 338 | } |
hudakz | 5:3b2c7e9fda3f | 339 |