NEC mPD780852 Series Preliminary User's Manual page 182

(b) Parity types and operations
The parity bit is used to detect bit errors in transfer data. Usually, the same type of parity bit is used by the
transmitting and receiving sides. When odd parity or even parity is set, errors in the parity bit (the odd-number
bit) can be detected. When zero parity or no parity is set, errors are not detected.
(i) Even parity
• During transmission
The number of bits in transmit data that includes a parity bit is controlled so that there are an even
number of "1" bits. The value of the parity bit is as follows.
If the transmit data contains an odd number of "1" bits:
If the transmit data contains an even number of "1" bits:
• During reception
The number of "1" bits is counted among the receive data that include a parity bit, and a parity error
occurs when the result is an odd number.
(ii) Odd parity
• During transmission
The number of bits in transmit data that includes a parity bit is controlled so that there is an odd number
of "1" bits. The value of the parity bit is as follows.
If the transmit data contains an odd number of "1" bits:
If the transmit data contains an even number of "1" bits:
• During reception
The number of "1" bits is counted among the receive data that include a parity bit, and a parity error
occurs when the result is an even number.
(iii) Zero parity
During transmission, the parity bit is set to "0" regardless of the transmit data.
During reception, the parity bit is not checked. Therefore, no parity errors will occur regardless of
whether the parity bit is a "0" or a "1".
(iv) No parity
No parity bit is added to the transmit data.
During reception, receive data is regarded as having no parity bit. Since there is no parity bit, no parity
errors will occur.
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CHAPTER 13 SERIAL INTERFACE UART
Preliminary User's Manual U14581EJ3V0UM00
the parity bit value is "1"
the parity bit value is "0"
the parity bit value is "0"
the parity bit value is "1"