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.

Diff: Manchester.h

Revision:
5:3b2c7e9fda3f
Parent:
2:de778df5892c
Child:
6:7454ad91f714
--- a/Manchester.h	Thu May 18 13:37:21 2017 +0000
+++ b/Manchester.h	Sun May 21 19:17:28 2017 +0000
@@ -26,12 +26,31 @@
  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+/*
+   This library implements Manchester code according to both IEEE 802.3 
+   and G.E. Thomas' convention. 
+   • 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 is one synchronization pulse at the begin of transmission 
+   
+   The IEEE 802.3 convention is used by default.
+   Select a convention to be used by commenting or uncommenting 
+   the line "#define G_E_THOMAS 1" below. 
+*/
+
 #ifndef MANCHESTER_H
 #define MANCHESTER_H
 
 #include "mbed.h"
 #include "ManchesterMsg.h"
 
+
+//Uncomment the following line to use G.E.Thomas' convention
+//#define G_E_THOMAS 1
+
 class   Manchester
 {
     enum State
@@ -53,8 +72,8 @@
     (
         PinName     txPin,          /* transmitter pin name */
         PinName     rxPin,          /* receiver pin name */
-        uint32_t    speed = 1200    /* speed in bits per second */,
-        uint8_t     tol = 20        /* pulse width tolerance (+/-) in % */
+        uint32_t    speed = 1200,   /* speed in bits per second */
+        uint8_t     tol = 25        /* pulse width tolerance (+/-) in % */
     );
     ~Manchester(void) { }
     void    transmit(ManchesterMsg& msg);