Description

Low Energy Universal Asynchronous Receiver/Transmitter (LEUART) Peripheral API.

This module contains functions to control the LEUART peripheral of Silicon Labs 32-bit MCUs and SoCs. The LEUART module provides the full UART communication using a low frequency 32.768 kHz clock and has special features for communication without the CPU intervention.

Data Structures
struct	LEUART_Init_TypeDef
	Initialization structure.

Functions
uint32_t	LEUART_BaudrateCalc (uint32_t refFreq, uint32_t clkdiv)
	Calculate the baudrate for the LEUART given reference frequency and clock division.

uint32_t	LEUART_BaudrateGet (LEUART_TypeDef *leuart)
	Get the current baudrate for LEUART.

void	LEUART_BaudrateSet (LEUART_TypeDef *leuart, uint32_t refFreq, uint32_t baudrate)
	Configure the baudrate (or as close as possible to a specified baudrate).

void	LEUART_Enable (LEUART_TypeDef *leuart, LEUART_Enable_TypeDef enable)
	Enable/disable the LEUART receiver and/or transmitter.

void	LEUART_FreezeEnable (LEUART_TypeDef *leuart, bool enable)
	LEUART register synchronization freeze control.

void	LEUART_Init (LEUART_TypeDef leuart, LEUART_Init_TypeDef const init)
	Initialize LEUART.

void	LEUART_TxDmaInEM2Enable (LEUART_TypeDef *leuart, bool enable)
	Enables handling of LEUART TX by DMA in EM2.

void	LEUART_RxDmaInEM2Enable (LEUART_TypeDef *leuart, bool enable)
	Enables handling of LEUART RX by DMA in EM2.

void	LEUART_IntClear (LEUART_TypeDef *leuart, uint32_t flags)
	Clear one or more pending LEUART interrupts.

void	LEUART_IntDisable (LEUART_TypeDef *leuart, uint32_t flags)
	Disable one or more LEUART interrupts.

void	LEUART_IntEnable (LEUART_TypeDef *leuart, uint32_t flags)
	Enable one or more LEUART interrupts.

uint32_t	LEUART_IntGet (LEUART_TypeDef *leuart)
	Get pending LEUART interrupt flags.

uint32_t	LEUART_IntGetEnabled (LEUART_TypeDef *leuart)
	Get enabled and pending LEUART interrupt flags.

void	LEUART_IntSet (LEUART_TypeDef *leuart, uint32_t flags)
	Set one or more pending LEUART interrupts from SW.

uint32_t	LEUART_StatusGet (LEUART_TypeDef *leuart)
	Get LEUART STATUS register.

void	LEUART_Reset (LEUART_TypeDef *leuart)
	Reset LEUART to the same state that it was in after a hardware reset.

uint8_t	LEUART_Rx (LEUART_TypeDef *leuart)
	Receive one 8 bit frame, (or part of 9 bit frame).

uint16_t	LEUART_RxExt (LEUART_TypeDef *leuart)
	Receive one 8-9 bit frame with extended information.

void	LEUART_Tx (LEUART_TypeDef *leuart, uint8_t data)
	Transmit one frame.

void	LEUART_TxExt (LEUART_TypeDef *leuart, uint16_t data)
	Transmit one 8-9 bit frame with extended control.

uint8_t	LEUART_RxDataGet (LEUART_TypeDef *leuart)
	Receive one 8 bit frame, (or part of a 9 bit frame).

uint16_t	LEUART_RxDataXGet (LEUART_TypeDef *leuart)
	Receive one 8-9 bit frame, with extended information.

Macros
#define	LEUART_INIT_DEFAULT
	Default configuration for LEUART initialization structure.

Enumerations
enum	LEUART_Databits_TypeDef { leuartDatabits8 = LEUART_CTRL_DATABITS_EIGHT, leuartDatabits9 = LEUART_CTRL_DATABITS_NINE }
	Data bit selection.

enum	LEUART_Enable_TypeDef { leuartDisable = 0x0, leuartEnableRx = LEUART_CMD_RXEN, leuartEnableTx = LEUART_CMD_TXEN, leuartEnable = (LEUART_CMD_RXEN \| LEUART_CMD_TXEN) }
	Enable selection.

enum	LEUART_Parity_TypeDef { leuartNoParity = LEUART_CTRL_PARITY_NONE, leuartEvenParity = LEUART_CTRL_PARITY_EVEN, leuartOddParity = LEUART_CTRL_PARITY_ODD }
	Parity selection.

enum	LEUART_Stopbits_TypeDef { leuartStopbits1 = LEUART_CTRL_STOPBITS_ONE, leuartStopbits2 = LEUART_CTRL_STOPBITS_TWO }
	Stop bits selection.

Function Documentation

◆ LEUART_BaudrateCalc()

uint32_t LEUART_BaudrateCalc	(	uint32_t	`refFreq,`
		uint32_t	`clkdiv`
	)

Calculate the baudrate for the LEUART given reference frequency and clock division.

This function returns the baudrate that a LEUART module will use if configured with the given frequency and clock divisor. Notice that this function will not use the hardware configuration. It can be used to determine if a given configuration is sufficiently accurate for the application.

Parameters

[in]	`refFreq`	The LEUART peripheral frequency used.
[in]	`clkdiv`	The clock division factor to be used.

Returns: A baudrate with given settings.

◆ LEUART_BaudrateGet()

uint32_t LEUART_BaudrateGet ( LEUART_TypeDef * leuart )

Get the current baudrate for LEUART.

This function returns the actual baudrate (not considering the oscillator inaccuracies) used by the LEUART peripheral.

Parameters

[in] leuart A pointer to the LEUART peripheral register block.

Returns: The current baudrate.

◆ LEUART_BaudrateSet()

void LEUART_BaudrateSet	(	LEUART_TypeDef *	`leuart,`
		uint32_t	`refFreq,`
		uint32_t	`baudrate`
	)

Configure the baudrate (or as close as possible to a specified baudrate).

Note: The baudrate setting requires synchronization into the low-frequency domain. If the same register is modified before a previous update has completed, this function will stall until the previous synchronization has completed.

Parameters

[in]	`leuart`	A pointer to the LEUART peripheral register block.
[in]	`refFreq`	The LEUART reference clock frequency in Hz that will be used. If set to 0, the currently configured reference clock is assumed.
[in]	`baudrate`	A baudrate to try to achieve for LEUART.

◆ LEUART_Enable()

void LEUART_Enable	(	LEUART_TypeDef *	`leuart,`
		LEUART_Enable_TypeDef	`enable`
	)

Enable/disable the LEUART receiver and/or transmitter.

Notice that this function does not do any configuration. Enabling should normally be done after the initialization is done (if not enabled as part of initialization).

Note: Enabling/disabling requires synchronization into the low-frequency domain. If the same register is modified before a previous update has completed, this function will stall until the previous synchronization has completed.

Parameters

[in]	`leuart`	A pointer to the LEUART peripheral register block.
[in]	`enable`	Select status for receiver/transmitter.

◆ LEUART_FreezeEnable()

void LEUART_FreezeEnable	(	LEUART_TypeDef *	`leuart,`
		bool	`enable`
	)

LEUART register synchronization freeze control.

Some LEUART registers require synchronization into the low-frequency (LF) domain. The freeze feature allows for several such registers to be modified before passing them to the LF domain simultaneously (which takes place when the freeze mode is disabled).

Note: When enabling freeze mode, this function will wait for all current ongoing LEUART synchronization to the LF domain to complete (Normally synchronization will not be in progress.) However, for this reason, when using freeze mode, modifications of registers requiring LF synchronization should be done within one freeze enable/disable block to avoid unnecessary stalling.

Parameters

[in]	`leuart`	A pointer to the LEUART peripheral register block.
[in]	`enable`	True - enable freeze, modified registers are not propagated to the LF domain False - disables freeze, modified registers are propagated to the LF domain

◆ LEUART_Init()

void LEUART_Init	(	LEUART_TypeDef *	`leuart,`
		LEUART_Init_TypeDef const *	`init`
	)

Initialize LEUART.

This function will configure basic settings to operate in normal asynchronous mode. Consider using LEUART_Reset() prior to this function if the state of configuration is not known, since only configuration settings specified by init are set.

Special control setup not covered by this function may be done either before or after using this function (but normally before enabling) by direct modification of the CTRL register.

Notice that pins used by the LEUART module must be properly configured by the user explicitly for the LEUART to work as intended. (When configuring pins consider the sequence of configuration to avoid unintended pulses/glitches on output pins.)

Note: Initializing requires synchronization into the low-frequency domain. If the same register is modified before a previous update has completed, this function will stall until the previous synchronization has completed.

Parameters

[in]	`leuart`	A pointer to the LEUART peripheral register block.
[in]	`init`	A pointer to the initialization structure used to configure basic async setup.

◆ LEUART_TxDmaInEM2Enable()

void LEUART_TxDmaInEM2Enable	(	LEUART_TypeDef *	`leuart,`
		bool	`enable`
	)

Enables handling of LEUART TX by DMA in EM2.

Parameters

[in]	`leuart`	A pointer to the LEUART peripheral register block.
[in]	`enable`	True - enables functionality False - disables functionality

◆ LEUART_RxDmaInEM2Enable()

void LEUART_RxDmaInEM2Enable	(	LEUART_TypeDef *	`leuart,`
		bool	`enable`
	)

Enables handling of LEUART RX by DMA in EM2.

Parameters

[in]	`leuart`	A pointer to the LEUART peripheral register block.
[in]	`enable`	True - enables functionality False - disables functionality

◆ LEUART_IntClear()

void LEUART_IntClear	(	LEUART_TypeDef *	`leuart,`
		uint32_t	`flags`
	)

inline

Clear one or more pending LEUART interrupts.

Parameters

[in]	`leuart`	Pointer to LEUART peripheral register block.
[in]	`flags`	Pending LEUART interrupt source to clear. Use a bitwise logic OR combination of valid interrupt flags for LEUART module (LEUART_IF_nnn).

◆ LEUART_IntDisable()

void LEUART_IntDisable	(	LEUART_TypeDef *	`leuart,`
		uint32_t	`flags`
	)

inline

Disable one or more LEUART interrupts.

Parameters

[in]	`leuart`	Pointer to LEUART peripheral register block.
[in]	`flags`	LEUART interrupt sources to disable. Use a bitwise logic OR combination of valid interrupt flags for LEUART module (LEUART_IF_nnn).

◆ LEUART_IntEnable()

void LEUART_IntEnable	(	LEUART_TypeDef *	`leuart,`
		uint32_t	`flags`
	)

inline

Enable one or more LEUART interrupts.

Note: Depending on the use, a pending interrupt may already be set prior to enabling the interrupt. To ignore a pending interrupt, consider using LEUART_IntClear() prior to enabling the interrupt.

Parameters

[in]	`leuart`	Pointer to LEUART peripheral register block.
[in]	`flags`	LEUART interrupt sources to enable. Use a bitwise logic OR combination of valid interrupt flags for LEUART module (LEUART_IF_nnn).

◆ LEUART_IntGet()

uint32_t LEUART_IntGet ( LEUART_TypeDef * leuart )

inline

Get pending LEUART interrupt flags.

Note: The event bits are not cleared by the use of this function.

Parameters

[in] leuart Pointer to LEUART peripheral register block.

Returns: LEUART interrupt sources pending. A bitwise logic OR combination of valid interrupt flags for LEUART module (LEUART_IF_nnn).

◆ LEUART_IntGetEnabled()

uint32_t LEUART_IntGetEnabled ( LEUART_TypeDef * leuart )

inline

Get enabled and pending LEUART interrupt flags.

Useful for handling more interrupt sources in the same interrupt handler.

Parameters

[in] leuart Pointer to LEUART peripheral register block.

Note: Interrupt flags are not cleared by the use of this function.

Returns

Pending and enabled LEUART interrupt sources. The return value is the bitwise AND combination of

the OR combination of enabled interrupt sources in LEUARTx_IEN_nnn register (LEUARTx_IEN_nnn) and
the OR combination of valid interrupt flags of LEUART module (LEUARTx_IF_nnn).

◆ LEUART_IntSet()

void LEUART_IntSet	(	LEUART_TypeDef *	`leuart,`
		uint32_t	`flags`
	)

inline

Set one or more pending LEUART interrupts from SW.

Parameters

[in]	`leuart`	Pointer to LEUART peripheral register block.
[in]	`flags`	LEUART interrupt sources to set to pending. Use a bitwise logic OR combination of valid interrupt flags for LEUART module (LEUART_IF_nnn).

◆ LEUART_StatusGet()

uint32_t LEUART_StatusGet ( LEUART_TypeDef * leuart )

inline

Get LEUART STATUS register.

Parameters

[in] leuart Pointer to LEUART peripheral register block.

Returns: STATUS register value.

◆ LEUART_Reset()

void LEUART_Reset ( LEUART_TypeDef * leuart )

Reset LEUART to the same state that it was in after a hardware reset.

Parameters

[in] leuart A pointer to the LEUART peripheral register block.

◆ LEUART_Rx()

uint8_t LEUART_Rx ( LEUART_TypeDef * leuart )

Receive one 8 bit frame, (or part of 9 bit frame).

This function is normally used to receive one frame when operating with frame length 8 bits. See LEUART_RxExt() for reception of 9 bit frames.

Notice that possible parity/stop bits are not considered a part of the specified frame bit length.

Note: This function will stall if the buffer is empty until data is received.

Parameters

[in] leuart A pointer to the LEUART peripheral register block.

Returns: Data received.

◆ LEUART_RxExt()

uint16_t LEUART_RxExt ( LEUART_TypeDef * leuart )

Receive one 8-9 bit frame with extended information.

This function is normally used to receive one frame and additional RX status information is required.

Note: This function will stall if buffer is empty until data is received.

Parameters

[in] leuart A pointer to the LEUART peripheral register block.

Returns: Data received.

◆ LEUART_Tx()

void LEUART_Tx	(	LEUART_TypeDef *	`leuart,`
		uint8_t	`data`
	)

Transmit one frame.

Depending on the frame length configuration, 8 (least significant) bits from data are transmitted. If the frame length is 9, 8 bits are transmitted from data and one bit as specified by the CTRL register, BIT8DV field. See LEUART_TxExt() for transmitting 9 bit frame with full control of all 9 bits.

Notice that possible parity/stop bits in asynchronous mode are not considered a part of the specified frame bit length.

Note: This function will stall if buffer is full until the buffer becomes available.

Parameters

[in]	`leuart`	A pointer to the LEUART peripheral register block.
[in]	`data`	Data to transmit. See details above for more info.

◆ LEUART_TxExt()

void LEUART_TxExt	(	LEUART_TypeDef *	`leuart,`
		uint16_t	`data`
	)

Transmit one 8-9 bit frame with extended control.

Notice that possible parity/stop bits in asynchronous mode are not considered a part of the specified frame bit length.

Note: This function will stall if the buffer is full until the buffer becomes available.

Parameters

[in]	`leuart`	A pointer to the LEUART peripheral register block.
[in]	`data`	Data to transmit with extended control. Least significant bit contains frame bits and additional control bits are available as documented in the reference manual (set to 0 if not used).

◆ LEUART_RxDataGet()

uint8_t LEUART_RxDataGet ( LEUART_TypeDef * leuart )

inline

Receive one 8 bit frame, (or part of a 9 bit frame).

Used to quickly receive one 8 bit frame by reading RXDATA register directly, without checking STATUS register for RXDATAV flag. This can be useful from RXDATAV interrupt handler, i.e., waiting is superfluous, in order to quickly read received data. Please refer to LEUART_RxDataXGet() for reception of 9 bit frames.

Note: Since this function does not check if the RXDATA register actually holds valid data, it should only be used in situations when it is certain that there is valid data, ensured by some external program routine, e.g., when handling an RXDATAV interrupt. The LEUART_Rx() is normally a better choice if the validity of the RXDATA register is not certain.; Notice that possible parity/stop bits are not considered part of specified frame bit length.

Parameters

[in] leuart Pointer to LEUART peripheral register block.

Returns: Data received.

◆ LEUART_RxDataXGet()

uint16_t LEUART_RxDataXGet ( LEUART_TypeDef * leuart )

inline

Receive one 8-9 bit frame, with extended information.

Used to quickly receive one 8-9 bit frame with extended information by reading RXDATAX register directly, without checking STATUS register for RXDATAV flag. This can be useful from RXDATAV interrupt handler, i.e., waiting is superfluous, in order to quickly read received data.

Note: Since this function does not check if the RXDATAX register actually holds valid data, it should only be used in situations when it is certain that there is valid data, ensured by some external program routine, e.g., when handling an RXDATAV interrupt. The LEUART_RxExt() is normally a better choice if the validity of the RXDATAX register is not certain.; Notice that possible parity/stop bits are not considered part of specified frame bit length.

Parameters

[in] leuart Pointer to LEUART peripheral register block.

Returns: Data received.

Macro Definition Documentation

◆ LEUART_INIT_DEFAULT

#define LEUART_INIT_DEFAULT

Value:

         {                                                                                         \
        
         leuartEnable,
         
          /* Enable RX/TX when initialization completed. */
         
         \
        
         0,
         
          /* Use current configured reference clock for configuring baud rate.*/
         
         \
        
         9600,
         
          /* 9600 bits/s. */
         
         \
        
         leuartDatabits8,
         
          /* 8 data bits. */
         
         \
        
         leuartNoParity,
         
          /* No parity. */
         
         \
        
         leuartStopbits1
         
          /* 1 stop bit. */
         
         \
        
         }

Default configuration for LEUART initialization structure.

Enumeration Type Documentation

◆ LEUART_Databits_TypeDef

enum LEUART_Databits_TypeDef

Data bit selection.

Enumerator
leuartDatabits8	8 data bits.
leuartDatabits9	9 data bits.

◆ LEUART_Enable_TypeDef

enum LEUART_Enable_TypeDef

Enable selection.

Enumerator
leuartDisable	Disable both receiver and transmitter.
leuartEnableRx	Enable receiver only, transmitter disabled.
leuartEnableTx	Enable transmitter only, receiver disabled.
leuartEnable	Enable both receiver and transmitter.

◆ LEUART_Parity_TypeDef

enum LEUART_Parity_TypeDef

Parity selection.

Enumerator
leuartNoParity	No parity.
leuartEvenParity	Even parity.
leuartOddParity	Odd parity.

◆ LEUART_Stopbits_TypeDef

enum LEUART_Stopbits_TypeDef

Stop bits selection.

Enumerator
leuartStopbits1	1 stop bits.
leuartStopbits2	2 stop bits.

LEUART - Low Energy UART

Description

Data Structures

Functions

Macros

Enumerations

Function Documentation

◆ LEUART_BaudrateCalc()

◆ LEUART_BaudrateGet()

◆ LEUART_BaudrateSet()

◆ LEUART_Enable()

◆ LEUART_FreezeEnable()

◆ LEUART_Init()

◆ LEUART_TxDmaInEM2Enable()

◆ LEUART_RxDmaInEM2Enable()

◆ LEUART_IntClear()

◆ LEUART_IntDisable()

◆ LEUART_IntEnable()

◆ LEUART_IntGet()

◆ LEUART_IntGetEnabled()

◆ LEUART_IntSet()

◆ LEUART_StatusGet()

◆ LEUART_Reset()

◆ LEUART_Rx()

◆ LEUART_RxExt()

◆ LEUART_Tx()

◆ LEUART_TxExt()

◆ LEUART_RxDataGet()

◆ LEUART_RxDataXGet()

Macro Definition Documentation

◆ LEUART_INIT_DEFAULT

Enumeration Type Documentation

◆ LEUART_Databits_TypeDef

◆ LEUART_Enable_TypeDef

◆ LEUART_Parity_TypeDef

◆ LEUART_Stopbits_TypeDef