How to extract the LSB from a byte in C and Python?

Question

I'm sending a byte to my Raspi 3 and my Arduino via Bluetooth Serial.

e.g. 0b00000011 (mode), 0b01000001 (mode), 0b10010000 (direction)

The LSB indicates if the byte is a direction command or a instruction to switch mode, so I need to extract it in Arduino C and in Python.

Does anyone know how to do this? Thanks in advance!

look at here: http://stackoverflow.com/questions/21341338/extract-lsb-bit-from-a-byte-in-python — arman, Apr 07 '17 at 20:49
The usual way to extract the value of certain bits of a number is to mask off the other bits with a bitwise "and" operation. Python and C spell that operator the same way: `&`. — John Bollinger, Apr 07 '17 at 20:51
Turn the integer into a [*binary* string](https://docs.python.org/3/library/functions.html#bin); get the last character, convert back to int. — wwii, Apr 07 '17 at 21:07

Dorin · Accepted Answer · 2017-04-09T09:46:51.587

1

Use a bit operation:

C code

char b = 0x01;

if( b & 0x01 ) {
   // LSB is set
}
else {
   // LSB is not set
}

Python code

b = 0x01
if (b&0x01)==0x01 :
    # LSB is set
else:
    # LSB is not set

LSB = Least Significant Bit (in your case)

edited Apr 09 '17 at 09:46

answered Apr 07 '17 at 21:18

Dorin

This error appears: Traceback (most recent call last): File "/home/pi/Desktop/test.py", line 11, in if ( b & 0x01 ): TypeError: unsupported operand type(s) for &: 'bytes' and 'int' – the_dani Apr 08 '17 at 16:01
Ok great, do you know how to do it in python? – the_dani Apr 09 '17 at 09:46

1 Answers1