
NUC126
Aug. 08, 2018
Page
750
of 943
Rev 1.03
NUC12
6 S
E
RI
E
S
T
E
CH
NI
CA
L R
E
F
E
RE
NCE
MA
NUA
L
0x55 0x33 and 0xAA will be 1, 1, 0, 0 and 1.
The UART controller also can play as an RS-485 addressable slave, the protocol-related error of
PARITYERR (UUART_PROTSTS[5]) can be acted as the address bit detection when the PARITYEN
(UUART_PROTCTL[1]),
EVENPARITY
(UUART_PROTCTL[2])
and
STICKEN
(UUART_PROTCTL[26]) were set. If the PARITYERR was set, it means that the address bit in the
received bus is detected otherwise, the data is received into Buffer.
6.20.5.10 Wake-up Function
The USCI Controller in UART mode supports wake-up system function. The wake-up source includes
incoming data and nCTS pin. Each wake-up source is described as follows:
(a) Incoming data wake-up
When system is in power-down and both of the WKEN (UUART_WKCTL [0]) and DATWKEN
(UUART_PROTCTL[9]) are set , the toggle of incoming data pin can wake-up the system. In order to
receive the incoming data after the system wake-up, the WAKECNT (UUART_PROTCTL[14:11]) shall
be set. These bits field of WAKECNT (UUART_PROTCTL [14:11]) indicate how many clock cycle
selected by f
PDS_CLK
do the controller can get the 1
st
bit (start bit) when the device is wakeup from
Power-down mode.
Note1:
By the WAKECNT is loaded into the hardware counter at the time of WKF
(UUART_WKSTS[0]) is clear so that the user shall clear the wakeup flag first to make sure the time
period of WAKECNT is closed to the wake time of system.
Note2:
In order to receive the incoming data, the relation between the selected clock stable and the
baud rate shall be take care. (for example: The stable time of HXT is 4096 clock period.
Power-down mode
CLK
USCIx_DAT0
(RXD)
WKF
stable count
CPU run
start
Note:
Stable count means HCLK source recovery stable count.
Figure 6.20-6 Incoming Data Wake-Up
(b) nCTS pin wake-up
When system is in power-down and both of the WKEN (UUART_WKCTL [0]) and CTSWKEN
(UUART_PROTCTL[10]) are set , the toggle of nCTS pin can wake-up the system.
Case 1(nCTS transition from low to high):
Power-down mode
CLK
USCIx_CTL0
(nCTS)
stable count
CPU run
WKF
Note:
Stable count means HCLK source recovery stable count.
Figure 6.20-7 nCTS Wake-Up Case 1