
RM0453 Rev 2
RM0453
Universal synchronous/asynchronous receiver transmitter (USART/UART)
1257
35.8 USART
registers
for a list of abbreviations used in register descriptions.
The peripheral registers have to be accessed by words (32 bits).
35.8.1
USART control register 1 [alternate] (USART_CR1)
Address offset: 0x00
Reset value: 0x0000 0000
The same register can be used in FIFO mode enabled (this section) and FIFO mode
disabled (next section).
FIFO mode enabled
2. RXFF flag is asserted if the USART receives n+1 data (n being the RXFIFO size): n data in the RXFIFO and 1 data in
USART_RDR. In Stop mode, USART_RDR is not clocked. As a result, this register is not written and once n data are
received and written in the RXFIFO, the RXFF interrupt is asserted (RXFF flag is not set).
3. When OVRDIS = 0.
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RXF
FIE
TXFEIE
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
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
TXFNFIE
TCIE
RXFNEIE IDLEIE
TE
RE
UESM
UE
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
Bit 31
RXFFIE
: RXFIFO Full interrupt enable
This bit is set and cleared by software.
0: Interrupt inhibited
1: USART interrupt generated when RXFF = 1 in the USART_ISR register
Bit 30
TXFEIE
: TXFIFO empty interrupt enable
This bit is set and cleared by software.
0: Interrupt inhibited
1: USART interrupt generated when TXFE = 1 in the USART_ISR register
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.