
M0A21/M0A23 Series
May 06, 2022
Page
431
of 746
Rev 1.02
M0
A21
/M
0
A
2
3
SE
RIES
TEC
H
NICAL
RE
FEREN
C
E
M
ANUAL
time-out detection for receiver. The transmitting data delay time between the last stop and the next start
bit can be programed by setting DLY (UART_TOUT[15:8]) register. The UART supports hardware auto-
flow control that provides programmable nRTS flow control trigger level. The number of data bytes in
RX FIFO is equal to or greater than RTSTRGLV (UART_FIFO[19:16]), the nRTS is de-asserted.
UART Line Control Function
The UART controller supports fully programmable serial-interface characteristics by setting the
UART_LINE register. User can program UART_LINE register for the word length, stop bit and parity bit
setting. Table 6.11-10 and Table 6.11-11 list the UART word, stop bit length and the parity bit settings.
NSB
(UART_LINE[2])
WLS
(UART_LINE[1:0])
Word Length (Bit)
Stop Length (Bit)
0
00
5
1
0
01
6
1
0
10
7
1
0
11
8
1
1
00
5
1.5
1
01
6
2
1
10
7
2
1
11
8
2
Table 6.11-10 UART Line Control of Word and Stop Length Setting
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 adding 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 6.11-11 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