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Initialization and de-initialization functions
Functions

Initialization and de-initialization functions
[UARTEx Exported Functions]

Extended Initialization and Configuration Functions. More...

Functions

HAL_StatusTypeDef HAL_RS485Ex_Init (UART_HandleTypeDef *huart, uint32_t Polarity, uint32_t AssertionTime, uint32_t DeassertionTime)
 Initialize the RS485 Driver enable feature according to the specified parameters in the UART_InitTypeDef and creates the associated handle.

Detailed Description

Extended Initialization and Configuration Functions. 

===============================================================================
            ##### Initialization and Configuration functions #####
 ===============================================================================
    [..]
    This subsection provides a set of functions allowing to initialize the USARTx or the UARTy
    in asynchronous mode.
      (+) For the asynchronous mode the parameters below can be configured:
        (++) Baud Rate
        (++) Word Length
        (++) Stop Bit
        (++) Parity: If the parity is enabled, then the MSB bit of the data written
             in the data register is transmitted but is changed by the parity bit.
        (++) Hardware flow control
        (++) Receiver/transmitter modes
        (++) Over Sampling Method
        (++) One-Bit Sampling Method
      (+) For the asynchronous mode, the following advanced features can be configured as well:
        (++) TX and/or RX pin level inversion
        (++) data logical level inversion
        (++) RX and TX pins swap
        (++) RX overrun detection disabling
        (++) DMA disabling on RX error
        (++) MSB first on communication line
        (++) auto Baud rate detection
    [..]
    The HAL_RS485Ex_Init() API follows the UART RS485 mode configuration
     procedures (details for the procedures are available in reference manual).

Depending on the frame length defined by the M1 and M0 bits (7-bit, 8-bit or 9-bit), the possible UART formats are listed in the following table.

Table 1. UART frame format. +-----------------------------------------------------------------------+ | M1 bit | M0 bit | PCE bit | UART frame | |---------|---------|-----------|---------------------------------------| | 0 | 0 | 0 | | SB | 8 bit data | STB | | |---------|---------|-----------|---------------------------------------| | 0 | 0 | 1 | | SB | 7 bit data | PB | STB | | |---------|---------|-----------|---------------------------------------| | 0 | 1 | 0 | | SB | 9 bit data | STB | | |---------|---------|-----------|---------------------------------------| | 0 | 1 | 1 | | SB | 8 bit data | PB | STB | | |---------|---------|-----------|---------------------------------------| | 1 | 0 | 0 | | SB | 7 bit data | STB | | |---------|---------|-----------|---------------------------------------| | 1 | 0 | 1 | | SB | 6 bit data | PB | STB | | +-----------------------------------------------------------------------+

Function Documentation

HAL_StatusTypeDef HAL_RS485Ex_Init ( UART_HandleTypeDef *  huart,
uint32_t  Polarity,
uint32_t  AssertionTime,
uint32_t  DeassertionTime 
)

Initialize the RS485 Driver enable feature according to the specified parameters in the UART_InitTypeDef and creates the associated handle.

Parameters:
huart,:UART handle.
Polarity,:select the driver enable polarity. This parameter can be one of the following values:

  • UART_DE_POLARITY_HIGH DE signal is active high
  • UART_DE_POLARITY_LOW DE signal is active low
AssertionTime,:Driver Enable assertion time: 5-bit value defining the time between the activation of the DE (Driver Enable) signal and the beginning of the start bit. It is expressed in sample time units (1/8 or 1/16 bit time, depending on the oversampling rate)
DeassertionTime,:Driver Enable deassertion time: 5-bit value defining the time between the end of the last stop bit, in a transmitted message, and the de-activation of the DE (Driver Enable) signal. It is expressed in sample time units (1/8 or 1/16 bit time, depending on the oversampling rate).
Return values:
HALstatus

Definition at line 166 of file stm32l4xx_hal_uart_ex.c.

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