RM0440 Rev 4 1729/2126
RM0440 Low-power universal asynchronous receiver transmitter (LPUART)
1733
38.6.9 LPUART interrupt flag clear register (LPUART_ICR)
Address offset: 0x20
Reset value: 0x0000 0000
Bit 2 NE: Start bit noise detection flag
This bit is set by hardware when noise is detected on the start bit of a received frame. It is
cleared by software, writing 1 to the NECF bit in the LPUART_ICR register.
0: No noise is detected
1: Noise is detected
Note: This bit does not generate an interrupt as it appears at the same time as the RXNE bit
which itself generates an interrupt. An interrupt is generated when the NE flag is set
during multi buffer communication if the EIE bit is set.
Bit 1 FE: Framing error
This bit is set by hardware when a de-synchronization, excessive noise or a break character
is detected. It is cleared by software, writing 1 to the FECF bit in the LPUART_ICR register.
When transmitting data in Smartcard mode, this bit is set when the maximum number of
transmit attempts is reached without success (the card NACKs the data frame).
An interrupt is generated if EIE = 1 in the LPUART_CR1 register.
0: No Framing error is detected
1: Framing error or break character is detected
Bit 0 PE: Parity error
This bit is set by hardware when a parity error occurs in receiver mode. It is cleared by
software, writing 1 to the PECF in the LPUART_ICR register.
An interrupt is generated if PEIE = 1 in the LPUART_CR1 register.
0: No parity error
1: Parity error
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
Res. Res. Res. Res. Res. Res. Res. Res. Res. Res. Res. WUCF Res. Res. CMCF Res.
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Res. Res. Res. Res. Res. Res. CTSCF Res. Res. TCCF Res. IDLECF ORECF NECF FECF PECF
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Bits 31:21 Reserved, must be kept at reset value.
Bit 20 WUCF: Wakeup from low-power mode clear flag
Writing 1 to this bit clears the WUF flag in the LPUART_ISR register.
Note: If the LPUART does not support the wakeup from Stop feature, this bit is reserved and
kept at reset value. Refer to Section 37.4: USART implementation.
Bits 19:18 Reserved, must be kept at reset value.
Bit 17 CMCF: Character match clear flag
Writing 1 to this bit clears the CMF flag in the LPUART_ISR register.
Bits 16:10 Reserved, must be kept at reset value.
Bit 9 CTSCF: CTS clear flag
Writing 1 to this bit clears the CTSIF flag in the LPUART_ISR register.
Bits 8:7 Reserved, must be kept at reset value.
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