manchester coding

[darvaish]

Can some body give me C code to Manchester encode and decode a byte of data .
I am using PIC18F452 mcu and C18 compiler.

I need a function like

Encode(byte in)
{
return (byte [2] manchester);
}

Decode(byte [2] manchester)
{
return(byte out);
}

 

[panic mode]

i never used it but if i remember correctly manchester code is very much
like regular binary code except that:
- each "0" is presented by two bits "10" (transition from high to low) and
- each "1" is presented by two bits "01" (transition from low to high).

so binary sequence 01101001
would look like 1001011001101001
when encoded.

this method is supposed to ensure alternations in long sequences
of same bit such as 000000 or 1111111.
with manchester code it is impossible to have more than two "0"s or two "1"s
side by side. if such scenario is detected, signal is considered faulty and
ignored. also if you had IR LEDs transmit sequence like
111111... they wouldn't last long.

 

[DirtyLude]

Here's sourcecode from the radiotronix website. It gives a CCS PIC C example for encoding / decoding using their transmitter recevier pair. You should be able to adapt it quite easily.

**broken link removed**