24.5.1 Parity Bit Calculation

The parity bit is calculated by doing an exclusive-or of all the data bits. If odd parity is used, the result of the exclusive or is inverted. The relation between the parity bit and data bits is as follows:

P_{even} = d_{n - 1} \oplus \dots \oplus d_{3} \oplus d_{2} \oplus d_{1} \oplus d_{0} \oplus 0

P_{odd} = d_{n - 1} \oplus \dots \oplus d_{3} \oplus d_{2} \oplus d_{1} \oplus d_{0} \oplus 1

P_even: Parity bit using even parity
P_odd: Parity bit using odd parity

d_n: Data bit n of the character

If used, the parity bit is located between the last data bit and first stop bit of a serial frame.

ATmega328PB

24.5.1 Parity Bit Calculation