Zoltan Hudak / Manchester Featured

Manchester code (phase encoding) library.

Dependents:   Manchester_Transmitter Manchester_Receiver

Manchester code (phase encoding) library

It implements Manchester code according to both IEEE 802.3 and G.E. Thomas' conventions.

  • A '0' is expressed by a high-to-low transition, a '1' by low-to-high transition in the IEEE 802.3 convention. The reverse is true in the G.E. Thomas' convention.
  • The transitions which signify '0' or '1' occur at the midpoint of a period.
  • Transitions at the start of a period are overhead and don't signify data.
  • Least significant bit is sent first
  • There are synchronization pulses (the number can be set) at the begin of transmission

    Select a convention to be used by commenting or uncommenting the line below in the Manchester.h header file.

Manchester.h

#define G_E_THOMAS 1

The IEEE 802.3 convention is used by default.

A Manchester encoded message (using G.E. Thomas' convention), with one sync pulse in the preamble, carrying four bytes:

/media/uploads/hudakz/manchester01.png

ACKNOWLEDGEMENT: The code in this library was based on this article published by Robert Guastella.

Import programManchester_Transmitter

Manchester transmitter demo.

Last commit 14 Oct 2018 by Zoltan Hudak


Import programManchester_Receiver

Manchester receiver demo.

Last commit 14 Oct 2018 by Zoltan Hudak

NOTE: To perform a simple test (without radio modules) connect the txPin on transmitter board to the rxPin on the receiver board and make sure that grounds are also connected one another.

ManchesterMsg.h@0:d5c75b0e5708, 2017-05-17 (annotated)

Committer:
hudakz
Date:
Wed May 17 07:52:15 2017 +0000
Revision:
0:d5c75b0e5708
Child:
2:de778df5892c
Initial issue.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
hudakz 0:d5c75b0e5708 1 /*
hudakz 0:d5c75b0e5708 2 ******************************************************************************
hudakz 0:d5c75b0e5708 3 * @file ManchesterMsg.h
hudakz 0:d5c75b0e5708 4 * @author Zoltan Hudak
hudakz 0:d5c75b0e5708 5 * @version
hudakz 0:d5c75b0e5708 6 * @date 16-May-2017
hudakz 0:d5c75b0e5708 7 * @brief Message container
hudakz 0:d5c75b0e5708 8 ******************************************************************************
hudakz 0:d5c75b0e5708 9 * @attention
hudakz 0:d5c75b0e5708 10 *
hudakz 0:d5c75b0e5708 11 * <h2><center>&copy; 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 0:d5c75b0e5708 28
hudakz 0:d5c75b0e5708 29 #ifndef MANCHESTERMSG_H
hudakz 0:d5c75b0e5708 30 #define MANCHESTERMSG_H
hudakz 0:d5c75b0e5708 31
hudakz 0:d5c75b0e5708 32 //#define DEBUG 1
hudakz 0:d5c75b0e5708 33
hudakz 0:d5c75b0e5708 34 /** ManchesterMsg class
hudakz 0:d5c75b0e5708 35 */
hudakz 0:d5c75b0e5708 36 class ManchesterMsg
hudakz 0:d5c75b0e5708 37 {
hudakz 0:d5c75b0e5708 38 unsigned char _max; // Max length (capacity) of data field in bytes
hudakz 0:d5c75b0e5708 39
hudakz 0:d5c75b0e5708 40 public:
hudakz 0:d5c75b0e5708 41 char* data; // Data field
hudakz 0:d5c75b0e5708 42 unsigned char len; // Length of data in bytes
hudakz 0:d5c75b0e5708 43
hudakz 0:d5c75b0e5708 44 /** Creates empty Manchester message of specified capacity.
hudakz 0:d5c75b0e5708 45 */
hudakz 0:d5c75b0e5708 46 ManchesterMsg(unsigned char max) :
hudakz 0:d5c75b0e5708 47 _max(max),
hudakz 0:d5c75b0e5708 48 data(new char[max]) { len = 0; }
hudakz 0:d5c75b0e5708 49
hudakz 0:d5c75b0e5708 50 ~ManchesterMsg(void) { delete[] data; }
hudakz 0:d5c75b0e5708 51
hudakz 0:d5c75b0e5708 52 /** Copy constructor.
hudakz 0:d5c75b0e5708 53 */
hudakz 0:d5c75b0e5708 54 ManchesterMsg(const ManchesterMsg& msg) {
hudakz 0:d5c75b0e5708 55 len = msg.len;
hudakz 0:d5c75b0e5708 56 memcpy(data, msg.data, msg.len);
hudakz 0:d5c75b0e5708 57 }
hudakz 0:d5c75b0e5708 58
hudakz 0:d5c75b0e5708 59
hudakz 0:d5c75b0e5708 60 /** Returns message maximum length (capacity)
hudakz 0:d5c75b0e5708 61 */
hudakz 0:d5c75b0e5708 62 unsigned char maxLen(void) { return _max; }
hudakz 0:d5c75b0e5708 63
hudakz 0:d5c75b0e5708 64 /** Clears message content
hudakz 0:d5c75b0e5708 65 */
hudakz 0:d5c75b0e5708 66 void clear(void) { len = 0; memset(data, 0, _max); }
hudakz 0:d5c75b0e5708 67
hudakz 0:d5c75b0e5708 68 /** Inserter operator: Appends data (value) to Manchester message
hudakz 0:d5c75b0e5708 69 */
hudakz 0:d5c75b0e5708 70 template<class T>
hudakz 0:d5c75b0e5708 71 ManchesterMsg &operator<<(const T val) {
hudakz 0:d5c75b0e5708 72 if(len + sizeof(T) <= _max) {
hudakz 0:d5c75b0e5708 73 *reinterpret_cast <T*> (&data[len]) = val;
hudakz 0:d5c75b0e5708 74 len += sizeof(T);
hudakz 0:d5c75b0e5708 75 }
hudakz 0:d5c75b0e5708 76
hudakz 0:d5c75b0e5708 77 #if DEBUG
hudakz 0:d5c75b0e5708 78 else {
hudakz 0:d5c75b0e5708 79 printf("Error: Cannot append data. Exceeding max data length!\r\n");
hudakz 0:d5c75b0e5708 80 }
hudakz 0:d5c75b0e5708 81 #endif
hudakz 0:d5c75b0e5708 82 return *this;
hudakz 0:d5c75b0e5708 83 }
hudakz 0:d5c75b0e5708 84
hudakz 0:d5c75b0e5708 85 /** Inserter operator: Appends string of char to Manchester message
hudakz 0:d5c75b0e5708 86 */
hudakz 0:d5c75b0e5708 87 ManchesterMsg &operator<<(const char* str) {
hudakz 0:d5c75b0e5708 88 unsigned char strLen = strlen(str);
hudakz 0:d5c75b0e5708 89 if(len + strLen + 1 <= _max) {
hudakz 0:d5c75b0e5708 90 memcpy(data + len, (char*)str, strLen);
hudakz 0:d5c75b0e5708 91 len += strLen;
hudakz 0:d5c75b0e5708 92 data[len++] = '\0';
hudakz 0:d5c75b0e5708 93 }
hudakz 0:d5c75b0e5708 94
hudakz 0:d5c75b0e5708 95 #if DEBUG
hudakz 0:d5c75b0e5708 96 else {
hudakz 0:d5c75b0e5708 97 printf("Error: Cannot append data. Exceeding max data length!\r\n");
hudakz 0:d5c75b0e5708 98 }
hudakz 0:d5c75b0e5708 99 #endif
hudakz 0:d5c75b0e5708 100 return *this;
hudakz 0:d5c75b0e5708 101 }
hudakz 0:d5c75b0e5708 102
hudakz 0:d5c75b0e5708 103 /** Extractor operator: Extracts data (value) from CAN message
hudakz 0:d5c75b0e5708 104 */
hudakz 0:d5c75b0e5708 105 template<class T>
hudakz 0:d5c75b0e5708 106 ManchesterMsg &operator>>(T& val) {
hudakz 0:d5c75b0e5708 107 if(sizeof(T) <= len) {
hudakz 0:d5c75b0e5708 108 val = *reinterpret_cast <T*> (&data[0]);
hudakz 0:d5c75b0e5708 109 len -= sizeof(T);
hudakz 0:d5c75b0e5708 110 memcpy(data, data + sizeof(T), len);
hudakz 0:d5c75b0e5708 111 }
hudakz 0:d5c75b0e5708 112
hudakz 0:d5c75b0e5708 113 #if DEBUG
hudakz 0:d5c75b0e5708 114 else {
hudakz 0:d5c75b0e5708 115 printf("Error: Cannot extract data. Exceeding data length!\r\n");
hudakz 0:d5c75b0e5708 116 }
hudakz 0:d5c75b0e5708 117 #endif
hudakz 0:d5c75b0e5708 118 return *this;
hudakz 0:d5c75b0e5708 119 }
hudakz 0:d5c75b0e5708 120 /** Extractor operator: Extracts string of char from CAN message
hudakz 0:d5c75b0e5708 121 */
hudakz 0:d5c75b0e5708 122 ManchesterMsg &operator>>(char* str) {
hudakz 0:d5c75b0e5708 123 unsigned char strLen = strlen(data);
hudakz 0:d5c75b0e5708 124 if(strLen <= len) {
hudakz 0:d5c75b0e5708 125 memcpy(str, data, strLen + 1);
hudakz 0:d5c75b0e5708 126 len -= (strLen + 1);
hudakz 0:d5c75b0e5708 127 memcpy(data, data + strLen + 1, len);
hudakz 0:d5c75b0e5708 128 }
hudakz 0:d5c75b0e5708 129
hudakz 0:d5c75b0e5708 130 #if DEBUG
hudakz 0:d5c75b0e5708 131 else {
hudakz 0:d5c75b0e5708 132 printf("Error: Cannot extract data. Exceeding data length!\r\n");
hudakz 0:d5c75b0e5708 133 }
hudakz 0:d5c75b0e5708 134 #endif
hudakz 0:d5c75b0e5708 135 return *this;
hudakz 0:d5c75b0e5708 136 }
hudakz 0:d5c75b0e5708 137 };
hudakz 0:d5c75b0e5708 138 #endif // MANCHESTERMSG_H