https://devzone.nordicsemi.com/f/nordic-q-a/50486/unexpected-behavior-with-bitwise-not-operator-in-if-statementI ran across something unexpected during development on our custom board today. I checked the behavior on an nRF52840-Preview-DK board and was able to reproduce it: This is the very simple code to reproduce the issue: All of the if() statementsen-USTelligent Community 13Thu, 01 Aug 2019 07:45:32 GMThttps://devzone.nordicsemi.com/thread/201759?ContentTypeID=1Thu, 01 Aug 2019 07:45:32 GMT137ad170-7792-4731-bb38-c0d22fbe4515:49172008-c5d5-4e05-ad46-18c3037694dcDmitry<p>Hi,</p> <p>you have declared your variables as uint8_t. As our CPU is 32-bit, all operations are performed with 32-bit values, and 8-bit variables are extended to 32 bits. In first three cases, 32-bit (~b) gives 0xffffff0d that is != 0x0d. In last case, result is shrinked to 8 bits to fit into 8-bit variable c, and result of comparison is false (0x0d == 0x0d).</p><div style="clear:both;"></div>