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NUC126
Aug. 08, 2018
Page
870
of 943
Rev 1.03
NUC12
6 S
E
RI
E
S
T
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CH
NI
CA
L R
E
F
E
RE
NCE
MA
NUA
L
Parity
Type
SPE
(UART_LINE[
5])
EPE
(UART_LINE[
4])
PSS
(UART_LINE[
7])
PBE
(UART_LINE[
3])
Description
No Parity
x
x
x
0
No parity bit output.
Parity
source
from
UART_DA
T
x
x
1
1
Parity bit is generated and checked by software.
Odd Parity
0
0
0
1
Odd Parity is calculated by add
ing all the “1’s” in a
data stream and adding a parity bit to the total bits,
to make the total count an odd number.
Even Parity
0
1
0
1
Even Parity is calculated by adding all the “1’s” in
a data stream and adding a parity bit to the total
bits, to make the count an even number.
Forced
Mask
Parity
1
0
0
1
Parity bit always logic 1.
Parity bit on the serial byte is set to “1” regardless
of total number of “1’s” (even or odd counts).
Forced
Space
Parity
1
1
0
1
Parity bit always logic 0.
Parity bit on the
serial byte is set to “0” regardless
of total number of “1’s” (even or odd counts).
Table 6.23-10 UART Line Control of Parity Bit Setting
UART Auto-Flow Control Function
The UART supports auto-flow control function that uses two signals, nCTS (clear-to-send) and nRTS
(request-to-send), to control the flow of data transfer between the UART and external devices (e.g.
Modem). When auto-flow is enabled, the UART is not allowed to receive data until the UART asserts
nRTS to external device. When the number of bytes stored in the RX FIFO equals the value of
RTSTRGLV (UART_FIFO [19:16]), the nRTS is de-asserted. The UART sends data out when UART
detects nCTS is asserted from external device. If the valid asserted nCTS is not detected, the UART
will not send data out.
APB BUS
RX FIFO
TX FIFO
Flow Control
Serial to Parallel
Serial to Parallel
UART_nCTS
UART_RXD
UART_nRTS
UART_TXD
Figure 6.23-11 Auto-Flow Control Block Diagram