Table 106. Noise Detection From Sampled Data; Figure 219. Data Sampling When Oversampling By 16; Figure 220. Data Sampling When Oversampling By 8 - ST STM32F410 Reference Manual

RM0401 Universal synchronous receiver transmitter (USART) /universal asynchronous receiver
When noise is detected in a frame:
• The NF bit is set at the rising edge of the RXNE bit.
•
The invalid data is transferred from the Shift register to the USART_DR register.
•
No interrupt is generated in case of single byte communication. However this bit rises
at the same time as the RXNE bit that itself generates an interrupt. In case of
multibuffer communication an interrupt will be issued if the EIE bit is set in the
USART_CR3 register.
The NF bit is reset by a USART_SR register read operation followed by a USART_DR
register read operation.
Note: Oversampling by 8 is not available in the Smartcard, IrDA and LIN modes. In those modes,
the OVER8 bit is forced to '0 by hardware.
receiver tolerance to clock

Figure 219. Data sampling when oversampling by 16

Figure 220. Data sampling when oversampling by 8

Table 106. Noise detection from sampled data

Sampled value
000
001
deviation). In this case the NF bit will never be set.
NE status
0
1
RM0401 Rev 3
Received bit value
0
0
639/771
679