code of program

[inwan96]

unsigned char frame_buffer [38] ; //buffer for frame
char frame_index = -1; // index in frame
char frame_size = -1 ; // size of the frame to be sent

//state variables of the manchester encoder
unsigned char bit_counter = 0 ;
unsigned short data_word = 0 ; //8bit data + start + stop
unsigned char half_bit = 0 ;
unsigned long int manchester_data ;

hy sir @jpiat , i don't understand the code above.
can you tell me please?