Interrupt And Status Register (Usart_Isr) - STMicroelectronics RM0365 Reference Manual

Universal synchronous asynchronous receiver transmitter (USART)
Bits 31:5 Reserved, must be kept at reset value
Bit 4 TXFRQ: Transmit data flush request
Bit 3 RXFRQ: Receive data flush request
Bit 2 MMRQ: Mute mode request
Bit 1 SBKRQ: Send break request
Note: In the case the application needs to send the break character following all previously
Bit 0 ABRRQ: Auto baud rate request
Note: If the USART does not support the auto baud rate feature, this bit is reserved and
29.8.8

Interrupt and status register (USART_ISR)

Address offset: 0x1C
Reset value: 0x0200 00C0
31 30 29
Res. Res. Res. Res.
15 14 13
ABRF ABRE Res. EOBF
r r
Bits 31:25 Reserved, must be kept at reset value.
Bits 24:23 Reserved, must be kept at reset value.
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Writing 1 to this bit sets the TXE flag.
This allows to discard the transmit data. This bit must be used only in Smartcard mode,
when data has not been sent due to errors (NACK) and the FE flag is active in the
USART_ISR register.
If the USART does not support Smartcard mode, this bit is reserved and forced by hardware
to '0'. Please refer to Section 29.4: USART implementation on page
Writing 1 to this bit clears the RXNE flag.
This allows to discard the received data without reading it, and avoid an overrun condition.
Writing 1 to this bit puts the USART in mute mode and sets the RWU flag.
Writing 1 to this bit sets the SBKF flag and request to send a BREAK on the line, as soon as
the transmit machine is available.
inserted data, including the ones not yet transmitted, the software should wait for the
TXE flag assertion before setting the SBKRQ bit.
Writing 1 to this bit resets the ABRF flag in the USART_ISR and request an automatic baud
rate measurement on the next received data frame.
forced by hardware to '0'. Please refer to
page 837.
28 27 26 25
Res. Res. Res.
12 11 10 9
RTOF CTS CTSIF
r r r r
Section 29.4: USART implementation on
24 23 22
Res. Res. REACK TEACK
r
8 7 6
LBDF TXE TC
r r r
DocID025202 Rev 7
837.
21 20 19 18
WUF RWU SBKF
r r r
5 4 3 2
RXNE IDLE ORE NF
r r r
RM0365
17 16
CMF BUSY
r r r
1 0
FE PE
r r r