Question

I have an unsigned char and I need to check bits 1 and 2 to find the status. What is the best way to determine the last 2 bits?

I am attempting to perform an OR, but my results aren’t correct. Any help would be appreciated. Thanks.

Example:

10101000 = off
10101001 = on
10101010 = error
10101011 = n/a

if(data_byte_data[0] | 0xfe)
    //01
else if(data_byte_data[0] | 0xfd)
    //10;
else if(data_byte_data[0] | 0xfc)
    //11
else if(data_byte_data[0] | 0xff)
    //00

Answer 1

I would do something like:

v = data_byte_data[0] & 0x03;
switch (v)
{
case 0: ...
case 1: ...
case 2: ...
case 3: ...
}