ST STM32F410 User Manual

Universal synchronous receiver transmitter (USART) /universal asynchronous receiver transmit-
652/771 RM0401 Rev 3
The USART receiver tolerance to properly receive data is equal to the maximum tolerated
deviation and depends on the following choices:
• 10- or 11-bit character length defined by the M bit in the USART_CR1 register
• oversampling by 8 or 16 defined by the OVER8 bit in the USART_CR1 register
• use of fractional baud rate or not
• use of 1 bit or 3 bits to sample the data, depending on the value of the ONEBIT bit in
the USART_CR3 register
Note: The figures specified in Table 119 and Table 120 may slightly differ in the special case when
the received frames contain some Idle frames of exactly 10-bit times when M=0 (11-bit times
when M=1).
24.4.6 Multiprocessor communication
There is a possibility of performing multiprocessor communication with the USART (several
USARTs connected in a network). For instance one of the USARTs can be the master, its TX
output is connected to the RX input of the other USART. The others are slaves, their
respective TX outputs are logically ANDed together and connected to the RX input of the
master.
In multiprocessor configurations it is often desirable that only the intended message
recipient should actively receive the full message contents, thus reducing redundant USART
service overhead for all non addressed receivers.
The non addressed devices may be placed in mute mode by means of the muting function.
In mute mode:
• None of the reception status bits can be set.
• All the receive interrupts are inhibited.
• The RWU bit in USART_CR1 register is set to 1. RWU can be controlled automatically
by hardware or written by the software under certain conditions.
The USART can enter or exit from mute mode using one of two methods, depending on the
WAKE bit in the USART_CR1 register:
• Idle Line detection if the WAKE bit is reset,
• Address Mark detection if the WAKE bit is set.
Table 119. USART receiver tolerance when DIV fraction is 0
M bit
OVER8 bit = 0 OVER8 bit = 1
ONEBIT=0 ONEBIT=1 ONEBIT=0 ONEBIT=1
0 3.75% 4.375% 2.50% 3.75%
1 3.41% 3.97% 2.27% 3.41%
Table 120. USART receiver tolerance when DIV_Fraction is different from 0
M bit
OVER8 bit = 0 OVER8 bit = 1
ONEBIT=0 ONEBIT=1 ONEBIT=0 ONEBIT=1
0 3.33% 3.88% 2% 3%
1 3.03% 3.53% 1.82% 2.73%

ST STM32F410 Specifications

General

Brand	ST
Model	STM32F410
Category	Microcontrollers
Language	English