Bit 4—Parity Mode (O/
E
):
Selects even or odd parity. The O/
E
bit setting is valid in
asynchronous mode when the PE bit is set to 1 to enable the adding and checking of a parity bit.
The O/
E
setting is ignored in synchronous mode, or when parity adding and checking is disabled
in asynchronous mode.
Bit 4
O/
E
Description
0
Even parity
*
1
(Initial value)
1
Odd parity
*
2
Notes: 1. When even parity is selected, the parity bit added to transmit data makes an even
number of 1s in the transmitted character and parity bit combined. Receive data must
have an even number of 1s in the received character and parity bit combined.
2. When odd parity is selected, the parity bit added to transmit data makes an odd number
of 1s in the transmitted character and parity bit combined. Receive data must have an
odd number of 1s in the received character and parity bit combined.
Bit 3—Stop Bit Length (STOP):
Selects one or two stop bits in asynchronous mode. This setting
is used only in asynchronous mode. In synchronous mode no stop bit is added, so the STOP bit
setting is ignored.
Bit 3
STOP
Description
0
One stop bit
*
1
(Initial value)
1
Two stop bits
*
2
Notes: 1. One stop bit (with value 1) is added at the end of each transmitted character.
2. Two stop bits (with value 1) are added at the end of each transmitted character.
In receiving, only the first stop bit is checked, regardless of the STOP bit setting. If the second
stop bit is 1 it is treated as a stop bit. If the second stop bit is 0 it is treated as the start bit of the
next incoming character.
445