
RM0453 Rev 2
RM0453
Universal synchronous/asynchronous receiver transmitter (USART/UART)
1257
35.8.2
USART control register 1 [alternate] (USART_CR1)
Address offset: 0x00
Reset value: 0x0000 0000
The same register can be used in FIFO mode enabled (previous section) and FIFO mode
disabled (this section).
FIFO mode disabled
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Res.
Res.
FIFO
EN
M1
EOBIE RTOIE
DEAT[4:0]
DEDT[4:0]
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
OVER8
CMIE
MME
M0
WAKE
PCE
PS
PEIE
TXEIE
TCIE
RXNEIE IDLEIE
TE
RE
UESM
UE
rw
rw
rw
rw
rw
rw
rw
rw
rw
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rw
rw
rw
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rw
Bits 31:30 Reserved, must be kept at reset value.
Bit 29
FIFOEN
: FIFO mode enable
This bit is set and cleared by software.
0: FIFO mode is disabled.
1: FIFO mode is enabled.
This bitfield can only be written when the USART is disabled (UE = 0).
Note: FIFO mode can be used on standard UART communication, in SPI master/slave mode
and in Smartcard modes only. It must not be enabled in IrDA and LIN modes.
Bit 28
M1
: Word length
This bit must be used in conjunction with bit 12 (M0) to determine the word length. It is set or
cleared by software.
M[1:0] = ‘00’: 1 start bit, 8 Data bits, n Stop bit
M[1:0] = ‘01’: 1 start bit, 9 Data bits, n Stop bit
M[1:0] = ‘10’: 1 start bit, 7 Data bits, n Stop bit
This bit can only be written when the USART is disabled (UE = 0).
Note: In 7-bits data length mode, the Smartcard mode, LIN master mode and Auto baud rate
(0x7F and 0x55 frames detection) are not supported.
Bit 27
EOBIE
: End of Block interrupt enable
This bit is set and cleared by software.
0: Interrupt inhibited
1: USART interrupt generated when the EOBF flag is set in the USART_ISR register
Note: If the USART does not support Smartcard mode, this bit is reserved and must be kept at
Section 35.4: USART implementation on page 1120
Bit 26
RTOIE
: Receiver timeout interrupt enable
This bit is set and cleared by software.
0: Interrupt inhibited
1: USART interrupt generated when the RTOF bit is set in the USART_ISR register.
Note: If the USART does not support the Receiver timeout feature, this bit is reserved and
must be kept at reset value.