
Serial interfaces
STM32W108CB, STM32W108HB
Doc ID 16252 Rev 3
9.12.2
UART configuration register (SC1_UARTCFG)
Address offset: 0xC85C
Reset value:
0x0000 0000
Bit 2 SC_UARTTXFREE: This bit is set when the transmit FIFO has space for at least one byte.
Bit 1 SC_UARTRXVAL: This bit is set when the receive FIFO contains at least one byte.
Bit 0 SC_UARTCTS: This bit is set when both the transmit FIFO and the transmit serializer are
empty.
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
SC_UA
RTAUT
O
SC_UA
RTFLO
W
SC_U
ARTO
DD
SC_UA
RTPAR
SC_UA
RT2ST
P
SC_UA
RT8BI
T
SC_UA
RTRTS
rw
Bit 6 SC_UARTAUTO: Set this bit to enable automatic nRTS control by hardware (SC_UARTFLOW
must also be set). When automatic control is enabled, nRTS will be deasserted when the
receive FIFO has space for only one more byte (inhibits transmission from the other device)
and will be asserted if it has space for more than one byte (enables transmission from the other
device). The SC_UARTRTS bit in this register has no effect if this bit is set.
Bit 5 SC_UARTFLOW: Set this bit to enable using nRTS/nCTS flow control signals. Clear this bit to
disable the signals. When this bit is clear, the UART transmitter will not be inhibited by nCTS.
Bit 4 SC_UARTODD: If parity is enabled, specifies the kind of parity.
0: Even parity.
1: Odd parity.
Bit 3 SC_UARTPAR: Specifies whether to use parity bits.
0: Don't use parity.
1: Use parity.
Bit 2 SC_UART2STP: Number of stop bits transmitted.
0: 1 stop bit.
1: 2 stop bits.
Bit 1 SC_UART8BIT: Number of data bits.
0: 7 data bits.
1: 8 data bits.
Bit 0 SC_UARTRTS: nRTS is an output to control the flow of serial data sent to the STM32W108
from another device. This bit directly controls the output at the nRTS pin (SC_UARTFLOW must
be set and SC_UARTAUTO must be cleared). When this bit is set, nRTS is asserted (pin is low,
'XON', RS232 positive voltage); the other device's transmission is enabled. When this bit is
cleared, nRTS is deasserted (pin is high, 'XOFF', RS232 negative voltage), the other device's
transmission is inhibited.