ST STM32F31xx

UM1581
Universal synchronous asynchronous receiver
transmitter (USART)
DocID023800 Rev 1
551/584
23.2.14.16 USART_SetPrescaler
Function Name
void USART_SetPrescaler ( USART_TypeDef * USARTx,
uint8_t USART_Prescaler)
Function Description
Sets the system clock prescaler.
Parameters
 USARTx : Select the USART peripheral. This parameter can
be one of the following values: USART1 or USART2 or
USART3 or UART4 or UART5.
 USART_Prescaler : specifies the prescaler clock.
Return values
 None.
Notes
 This function has to be called before calling USART_Cmd()
function.
23.2.15 RS485 mode function
23.2.15.1 USART_DECmd
Function Name
void USART_DECmd ( USART_TypeDef * USARTx,
FunctionalState NewState)
Function Description
Enables or disables the USART's DE functionality.
Parameters
 USARTx : Select the USART peripheral. This parameter can
be one of the following values: USART1 or USART2 or
USART3 or UART4 or UART5.
 NewState : new state of the driver enable mode. This
parameter can be: ENABLE or DISABLE.
Return values
 None.
Notes
 None.
23.2.15.2 USART_DEPolarityConfig
Function Name
void USART_DEPolarityConfig ( USART_TypeDef * USARTx,
uint32_t USART_DEPolarity)