ST STM32L0x3 User Manual

Universal synchronous/asynchronous receiver transmitter (USART/UART) RM0367
782/1043 RM0367 Rev 7
where
DWU is the error due to sampling point deviation when the wakeup from Stop mode is
used.
when M[1:0] = 01:
when M[1:0] = 00:
when M[1:0] = 10:
t
WUUSART
is the time between:
– The detection of start bit falling edge
– The instant when clock (requested by the peripheral) is ready and reaching the
peripheral and regulator is ready.
t
WUUSART
corresponds to t
WUSTOP
value provided in the datasheet.
The USART receiver can receive data correctly at up to the maximum tolerated
deviation specified in Table 142 and Table 143 depending on the following choices:
• 9-, 10- or 11-bit character length defined by the M bits in the USART_CR1 register
• Oversampling by 8 or 16 defined by the OVER8 bit in the USART_CR1 register
• Bits BRR[3:0] of USART_BRR register are equal to or different from 0000.
• Use of 1 bit or 3 bits to sample the data, depending on the value of the ONEBIT bit in
the USART_CR3 register.
Table 142. Tolerance of the USART receiver when BRR [3:0] = 0000
M bits
OVER8 bit = 0 OVER8 bit = 1
ONEBIT=0 ONEBIT=1 ONEBIT=0 ONEBIT=1
00 3.75% 4.375% 2.50% 3.75%
01 3.41% 3.97% 2.27% 3.41%
10 4.16% 4.86% 2.77% 4.16%
Table 143. Tolerance of the USART receiver when BRR [3:0] is different from 0000
M bits
OVER8 bit = 0 OVER8 bit = 1
ONEBIT=0 ONEBIT=1 ONEBIT=0 ONEBIT=1
00 3.33% 3.88% 2% 3%
01 3.03% 3.53% 1.82% 2.73%
10 3.7% 4.31% 2.22% 3.33%
DWU
t
WUUSART
11 Tbit×
---------------------------=
DWU
t
WUUSART
10 Tbit×
---------------------------=
DWU
t
WUUSART
9Tbit×
---------------------------=

ST STM32L0x3 Specifications

General

Brand	ST
Model	STM32L0x3
Category	Microcontrollers
Language	English