Coding/Decoding Manchester

Hardware Arduino Due
1

Hello,

There is some library to carry out the coding and decoding in manchester code that works for the arduino DUE.

Thanks.

2

I don't know any Manchester library for the DUE, however it should be rather easy to alter a Serialx (x = 1,2,3 or 4) to code/decode with the Manchester method thru a USARTn since, for what I have seen( in Manchester chapter, from page 782 of Sam3x datasheet), only US_MR and US_MAN registers are concerned.

The datasheet states:

When the Manchester encoder is in use, characters transmitted through the USART are encoded based on biphase Manchester II format.

Therefore the first question you have to answer is: does the equipment supposed to communicate with the DUE will be able to use the same Manchester Format ?

3

Yes, since the idea is to use an Arduino DUE to transmit and another Arduino DUE to receive

4

Then you could try firstly to alter the code of USART1 and USART2 in the basic sketch below within a single DUE board.

Connect a jumper between RX1 and TX2 and another one between RX2 and TX1, keep Serial1.begin() and Serial2.begin() to initialize a bunch of registers, then alter US_MR and US_MAN of USART0 (Serial1) and USART1(Serial2) as per datasheet.

char c = 0;
void setup() {
 
  Serial.begin(250000);
  Serial1.begin(1000000);
  Serial2.begin(1000000);

  Serial2.print("Hello");
}


void loop() {
  String s;
  s = "";

  while (Serial1.available() > 0) {
    c = Serial1.read();
    s += c;

  }
  if (s.length() > 0) {
    Serial.println(s);
    Serial2.print(s);
  }
  delay(1000);
}
5

Ok, it works. Thanks.

I understand that the coding and decoding is done internally. My question is there is some way to get that coding, for example, if Hello is coded by 0101, I can get that 0101.

The idea was to make a LI-FI system, the arduino transmitter transmits the data through a led and the receiver receives the data through a photoreceptor. That's why I need to encode the data and transmit the 0101 and the other Arduino decodes it and gets the Hello.

Any ideas?

6

I guess if you connect an led to TX1 and a photoresistor to RX2, you will transmit and receive Manchester encoded signals, provided you previously modified the register accordingly.

Page 782:

An example of Manchester encoded sequence is: the byte 0xB1 or 10110001 encodes to 10 01 10 10 01 01 01 10, assuming the default polarity of the encoder. Figure 35-8 illustrates this coding scheme.

7

Thank you very much for your help.

When you say this "As long as you have previously modified the record accordingly",
Do you mean these registers US_MR and US_MAN?

8

Yes, mostly US_MR and US_MAN are concerned.

Is it a uni assignment ?

9

I am reading and testing but I do not know how to configure US_MR and US_MAN, any help? :confused: