Control Register 1 (Usart_Cr1) - ST STM32F102 Series Reference Manual

Universal synchronous asynchronous receiver transmitter (USART)
24.6.4

Control register 1 (USART_CR1)

Address offset: 0x0C
Reset value: 0x0000
31 30 29
15 14 13
Reserved UE
Res. rw
Bits 31:14 Reserved, forced by hardware to 0.
Bit 13 UE: USART Enable.
When this bit is cleared the USART prescalers and outputs are stopped and the end of the current
byte transfer in order to reduce power consumption. This bit is set and cleared by software.
0: USART prescaler and outputs disabled
1: USART enabled
Bit 12 M: word length.
This bit determines the word length. It is set or cleared by software.
0: 1 Start bit, 8 Data bits, n Stop bit
1: 1 Start bit, 9 Data bits, 1 Stop bit
Note:
The M bit must not be modified during a data transfer (both transmission and reception)
Bit 11 WAKE: Wakeup method.
This bit determines the USART wakeup method, it is set or cleared by software.
0: Idle Line
1: Address Mark
Bit 10 PCE: Parity Control Enable.
This bit selects the hardware parity control (generation and detection). When the parity control is
enabled, the computed parity is inserted at the MSB position (9th bit if M=1; 8th bit if M=0) and
parity is checked on the received data. This bit is set and cleared by software. Once it is set, PCE is
active after the current byte (in reception and in transmission).
0: Parity control disabled
1: Parity control enabled
Bit 9 PS: Parity Selection.
This bit selects the odd or even parity when the parity generation/detection is enabled (PCE bit set).
It is set and cleared by software. The parity will be selected after the current byte.
0: Even parity
1: Odd parity
Bit 8 PEIE: PE Interrupt Enable.
This bit is set and cleared by software.
0: Interrupt is inhibited
1: An USART interrupt is generated whenever PE=1 in the USART_SR register
Bit 7 TXEIE: TXE Interrupt Enable.
This bit is set and cleared by software.
0: Interrupt is inhibited
1: An USART interrupt is generated whenever TXE=1 in the USART_SR register
642/690
28 27 26 25
12 11 10 9
M WAKE PCE PS
rw rw rw rw
24 23 22 21
Reserved
8 7 6 5
RXNE
PEIE TXEIE TCIE
IE
rw rw rw rw
20 19 18 17
4 3 2
IDLEIE TE RE RWU
rw rw rw rw
RM0008
16
1 0
SBK
rw