Initialization and Configuration functions.
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Initialization and Configuration functions.
===============================================================================
Initialization and Configuration functions
===============================================================================
This subsection provides a set of functions allowing to initialize the USART
in asynchronous and in synchronous modes.
- For the asynchronous mode only these parameters 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.
Depending on the frame length defined by the M bit (8-bits or 9-bits),
the possible USART frame formats are as listed in the following table:
+-------------------------------------------------------------+
| M bit | PCE bit | USART frame |
|---------------------|---------------------------------------|
| 0 | 0 | | SB | 8 bit data | STB | |
|---------|-----------|---------------------------------------|
| 0 | 1 | | SB | 7 bit data | PB | STB | |
|---------|-----------|---------------------------------------|
| 1 | 0 | | SB | 9 bit data | STB | |
|---------|-----------|---------------------------------------|
| 1 | 1 | | SB | 8 bit data | PB | STB | |
+-------------------------------------------------------------+
- Hardware flow control
- Receiver/transmitter modes
The USART_Init() function follows the USART asynchronous configuration procedure
(details for the procedure are available in reference manual (RM0090)).
- For the synchronous mode in addition to the asynchronous mode parameters these
parameters should be also configured:
- USART Clock Enabled
- USART polarity
- USART phase
- USART LastBit
These parameters can be configured using the USART_ClockInit() function.
Initializes the USARTx peripheral Clock according to the specified parameters in the USART_ClockInitStruct .
- Parameters
-
| USARTx,: | where x can be 1, 2, 3 or 6 to select the USART peripheral. |
| USART_ClockInitStruct,: | pointer to a USART_ClockInitTypeDef structure that contains the configuration information for the specified USART peripheral. |
- Note
- The Smart Card and Synchronous modes are not available for UART4 and UART5.
- Return values
-
Fills each USART_ClockInitStruct member with its default value.
- Parameters
-
- Return values
-
| void USART_Cmd |
( |
USART_TypeDef * |
USARTx, |
|
|
FunctionalState |
NewState |
|
) |
| |
Enables or disables the specified USART peripheral.
- Parameters
-
| USARTx,: | where x can be 1, 2, 3, 4, 5 or 6 to select the USART or UART peripheral. |
| NewState,: | new state of the USARTx peripheral. This parameter can be: ENABLE or DISABLE. |
- Return values
-
| void USART_DeInit |
( |
USART_TypeDef * |
USARTx | ) |
|
Deinitializes the USARTx peripheral registers to their default reset values.
- Parameters
-
| USARTx,: | where x can be 1, 2, 3, 4, 5 or 6 to select the USART or UART peripheral. |
- Return values
-
Initializes the USARTx peripheral according to the specified parameters in the USART_InitStruct .
- Parameters
-
| USARTx,: | where x can be 1, 2, 3, 4, 5 or 6 to select the USART or UART peripheral. |
| USART_InitStruct,: | pointer to a USART_InitTypeDef structure that contains the configuration information for the specified USART peripheral. |
- Return values
-
| void USART_OneBitMethodCmd |
( |
USART_TypeDef * |
USARTx, |
|
|
FunctionalState |
NewState |
|
) |
| |
Enables or disables the USART's one bit sampling method.
- Parameters
-
| USARTx,: | where x can be 1, 2, 3, 4, 5 or 6 to select the USART or UART peripheral. |
| NewState,: | new state of the USART one bit sampling method. This parameter can be: ENABLE or DISABLE. |
- Return values
-
| void USART_OverSampling8Cmd |
( |
USART_TypeDef * |
USARTx, |
|
|
FunctionalState |
NewState |
|
) |
| |
Enables or disables the USART's 8x oversampling mode.
- Note
- This function has to be called before calling USART_Init() function in order to have correct baudrate Divider value.
- Parameters
-
| USARTx,: | where x can be 1, 2, 3, 4, 5 or 6 to select the USART or UART peripheral. |
| NewState,: | new state of the USART 8x oversampling mode. This parameter can be: ENABLE or DISABLE. |
- Return values
-
| void USART_SetPrescaler |
( |
USART_TypeDef * |
USARTx, |
|
|
uint8_t |
USART_Prescaler |
|
) |
| |
Sets the system clock prescaler.
- Parameters
-
| USARTx,: | where x can be 1, 2, 3, 4, 5 or 6 to select the USART or UART peripheral. |
| USART_Prescaler,: | specifies the prescaler clock. |
- Note
- The function is used for IrDA mode with UART4 and UART5.
- Return values
-
Fills each USART_InitStruct member with its default value.
- Parameters
-
| USART_InitStruct,: | pointer to a USART_InitTypeDef structure which will be initialized. |
- Return values
-
1.8.3.1