RS485 mode function.
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RS485 mode function.
===============================================================================
##### RS485 mode functions #####
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[..] This subsection provides a set of functions allowing to manage the USART
RS485 flow control.
[..] RS485 flow control (Driver enable feature) handling is possible through
the following procedure:
(#) Program the Baud rate, Word length = 8 bits, Stop bits, Parity,
Transmitter/Receiver modes and hardware flow control values using
the USART_Init() function.
(#) Enable the Driver Enable using the USART_DECmd() function.
(#) Configures the Driver Enable polarity using the USART_DEPolarityConfig()
function.
(#) Configures the Driver Enable assertion time using USART_SetDEAssertionTime()
function and deassertion time using the USART_SetDEDeassertionTime()
function.
(#) Enable the USART using the USART_Cmd() function.
-@-
(+@) The assertion and dessertion times are expressed in sample time units (1/8 or
1/16 bit time, depending on the oversampling rate).
void USART_DECmd |
( |
USART_TypeDef * |
USARTx, |
|
|
FunctionalState |
NewState |
|
) |
| |
Enables or disables the USART's DE functionality.
- Parameters
-
USARTx,: | where x can be 1 or 2 or 3 to select the USART peripheral. |
NewState,: | new state of the driver enable mode. This parameter can be: ENABLE or DISABLE. |
- Return values
-
void USART_DEPolarityConfig |
( |
USART_TypeDef * |
USARTx, |
|
|
uint32_t |
USART_DEPolarity |
|
) |
| |
Configures the USART's DE polarity.
- Parameters
-
USARTx,: | where x can be 1 or 2 or 3 to select the USART peripheral. |
USART_DEPolarity,: | specifies the DE polarity. This parameter can be one of the following values:
- USART_DEPolarity_Low
- USART_DEPolarity_High
|
- Return values
-
void USART_SetDEAssertionTime |
( |
USART_TypeDef * |
USARTx, |
|
|
uint32_t |
USART_DEAssertionTime |
|
) |
| |
Sets the specified RS485 DE assertion time.
- Parameters
-
USARTx,: | where x can be 1 or 2 or 3 to select the USART peripheral. |
USART_DEAssertionTime,: | specifies the time between the activation of the DE signal and the beginning of the start bit |
- Return values
-
void USART_SetDEDeassertionTime |
( |
USART_TypeDef * |
USARTx, |
|
|
uint32_t |
USART_DEDeassertionTime |
|
) |
| |
Sets the specified RS485 DE deassertion time.
- Parameters
-
USARTx,: | where x can be 1 or 2 or 3 to select the USART peripheral. |
USART_DeassertionTime,: | specifies the time between the middle of the last stop bit in a transmitted message and the de-activation of the DE signal |
- Return values
-