Universal synchronous asynchronous receiver transmitter (USART) RM0390
798/1328 RM0390 Rev 4
Figure 279. USART block diagram
Wakeup
unit
Receiver
control
SR
Transmit
control
TXETC RXNEIDLEORE NF FE
USART
control
interrupt
CR1
M WAKE
Receive data register (RDR)
Receive Shift Register
Read
Transmit data register (TDR)
Transmit Shift Register
Write
SW_RX
TX
(Data register) DR
Transmitter
clock
Receiver
clock
Receiver rate
Transmitter rate
f
PCLKx(x=1,2)
control
control
/
[8 x (2 - OVER8)]
Conventional baud rate generator
SBKRWURETE
IDLERXNE
TCIETXEIE
CR1
UE PCE PS
PEIE
PE
PWDATA
IRLP
SCEN
IREN
DMAR
DMAT
USART Address
CR2
CR3
IrDA
SIR
ENDEC
block
LINE
CKEN CPOL
CPHA LBCL
SCLK control
SCLK
CR2
GT
STOP[1:0]
NACK
DIV_Mantissa
15
0
RE
USART_BRR
/USARTDIV
TE
HD
(CPU or DMA)
(CPU or DMA)
PRDATA
Hardware
flow
controller
CTS LBD
RX
IRDA_OUT
IRDA_IN
nRTS
nCTS
GTPR
PSC
IE
IE
DIV_Fraction
4
USARTDIV = DIV_Mantissa + (DIV_Fraction / 8 × (2 – OVER8))
SAMPLING
CR1
OVER8
DIVIDER
ai16099