158
CHAPTER 11 SERIAL INTERFACE CHANNEL 2
(b) Parity types and operation
The parity bit is used to detect a bit error in the communication data. Normally, the same kind of parity
bit is used on the transmitting side and the receiving side. With even parity and odd parity, a one-bit (odd
number) error can be detected. With 0 parity and no parity, an error cannot be detected.
(i)
Even parity
• Transmission
The number of bits with a value of “1”, including the parity bit, in the transmit data is controlled to
be even.
The value of the parity bit is as follows:
Number of bits with a value of “1” in transmit data is odd: 1
Number of bits with a value of “1” in transmit data is even: 0
• Reception
The number of bits with a value of “1”, including the parity bit, in the receive data is counted. If
it is odd, a parity error occurs.
(ii) Odd parity
• Transmission
Conversely to the situation with even parity, the number of bits with a value of “1”, including the
parity bit, in the transmit data is controlled to be odd. The value of the parity bit is as follows:
Number of bits with a value of “1” in transmit data is odd: 0
Number of bits with a value of “1” in transmit data is even: 1
• Reception
The number of bits with a value of “1”, including the parity bit, in the receive data is counted. If
it is even, a parity error occurs.
(iii) 0 Parity
When transmitting, the parity bit is set to "0" irrespective of the transmit data.
At reception, a parity bit check is not performed. Therefore, a parity error is not generated, irrespective
of whether the parity bit is set to "0" or "1".
(iv) No parity
A parity bit is not added to the transmit data. At reception, data is received assuming that there is
no parity bit. Since there is no parity bit, a parity error is not generated.
Содержание NEC PD78081(A)
Страница 23: ...xii MEMO...
Страница 37: ...14 CHAPTER 1 OUTLINE MEMO...
Страница 47: ...24 CHAPTER 2 PIN FUNCTION MEMO...
Страница 91: ...68 CHAPTER 4 PORT FUNCTIONS MEMO...
Страница 125: ...102 CHAPTER 6 8 BIT TIMER EVENT COUNTERS 5 AND 6 MEMO...
Страница 157: ...134 CHAPTER 10 A D CONVERTER MEMO...
Страница 193: ...170 CHAPTER 11 SERIAL INTERFACE CHANNEL 2 MEMO...
Страница 253: ...230 CHAPTER 16 INSTRUCTION SET MEMO...
Страница 269: ...246 APPENDIX B EMBEDDED SOFTWARE MEMO...