Description

Inter-integrated Circuit (I2C) Peripheral API.

This module contains functions to control the I2C peripheral of Silicon Labs 32-bit MCUs and SoCs. The I2C interface allows communication on I2C buses with the lowest energy consumption possible.

Data Structures
struct	I2C_Init_TypeDef
	I2C initialization structure.

struct	I2C_TransferSeq_TypeDef
	Master mode transfer message structure used to define a complete I2C transfer sequence (from start to stop).

Functions
uint32_t	I2C_BusFreqGet (I2C_TypeDef *i2c)
	Get the current configured I2C bus frequency.

void	I2C_BusFreqSet (I2C_TypeDef *i2c, uint32_t freqRef, uint32_t freqScl, I2C_ClockHLR_TypeDef i2cMode)
	Set the I2C bus frequency.

void	I2C_Enable (I2C_TypeDef *i2c, bool enable)
	Enable/disable I2C.

void	I2C_Init (I2C_TypeDef i2c, const I2C_Init_TypeDef init)
	Initialize I2C.

void	I2C_IntClear (I2C_TypeDef *i2c, uint32_t flags)
	Clear one or more pending I2C interrupts.

void	I2C_IntDisable (I2C_TypeDef *i2c, uint32_t flags)
	Disable one or more I2C interrupts.

void	I2C_IntEnable (I2C_TypeDef *i2c, uint32_t flags)
	Enable one or more I2C interrupts.

uint32_t	I2C_IntGet (I2C_TypeDef *i2c)
	Get pending I2C interrupt flags.

uint32_t	I2C_IntGetEnabled (I2C_TypeDef *i2c)
	Get enabled and pending I2C interrupt flags.

void	I2C_IntSet (I2C_TypeDef *i2c, uint32_t flags)
	Set one or more pending I2C interrupts from SW.

void	I2C_Reset (I2C_TypeDef *i2c)
	Reset I2C to the same state that it was in after a hardware reset.

uint8_t	I2C_SlaveAddressGet (I2C_TypeDef *i2c)
	Get slave address used for I2C peripheral (when operating in slave mode).

void	I2C_SlaveAddressSet (I2C_TypeDef *i2c, uint8_t addr)
	Set slave address to use for I2C peripheral (when operating in slave mode).

uint8_t	I2C_SlaveAddressMaskGet (I2C_TypeDef *i2c)
	Get slave address mask used for I2C peripheral (when operating in slave mode).

void	I2C_SlaveAddressMaskSet (I2C_TypeDef *i2c, uint8_t mask)
	Set slave address mask used for I2C peripheral (when operating in slave mode).

I2C_TransferReturn_TypeDef	I2C_Transfer (I2C_TypeDef *i2c)
	Continue an initiated I2C transfer (single master mode only).

I2C_TransferReturn_TypeDef	I2C_TransferInit (I2C_TypeDef i2c, I2C_TransferSeq_TypeDef seq)
	Prepare and start an I2C transfer (single master mode only).

Macros
#define	I2C_FREQ_STANDARD_MAX 93000
	Standard mode max frequency assuming using 4:4 ratio for Nlow:Nhigh.

#define	I2C_FREQ_FAST_MAX 392157
	Fast mode max frequency assuming using 6:3 ratio for Nlow:Nhigh.

#define	I2C_FREQ_FASTPLUS_MAX 987167
	Fast mode+ max frequency assuming using 11:6 ratio for Nlow:Nhigh.

#define	I2C_FLAG_WRITE 0x0001
	Indicate plain write sequence: S+ADDR(W)+DATA0+P.

#define	I2C_FLAG_READ 0x0002
	Indicate plain read sequence: S+ADDR(R)+DATA0+P.

#define	I2C_FLAG_WRITE_READ 0x0004
	Indicate combined write/read sequence: S+ADDR(W)+DATA0+Sr+ADDR(R)+DATA1+P.

#define	I2C_FLAG_WRITE_WRITE 0x0008
	Indicate write sequence using two buffers: S+ADDR(W)+DATA0+DATA1+P.

#define	I2C_FLAG_10BIT_ADDR 0x0010
	Use 10 bit address.

#define	I2C_INIT_DEFAULT
	Suggested default configuration for I2C initialization structure.

Enumerations
enum	I2C_ClockHLR_TypeDef { i2cClockHLRStandard = _I2C_CTRL_CLHR_STANDARD, i2cClockHLRAsymetric = _I2C_CTRL_CLHR_ASYMMETRIC, i2cClockHLRFast = _I2C_CTRL_CLHR_FAST }
	Clock low to high ratio settings.

enum	I2C_TransferReturn_TypeDef { i2cTransferInProgress = 1, i2cTransferDone = 0, i2cTransferNack = -1, i2cTransferBusErr = -2, i2cTransferArbLost = -3, i2cTransferUsageFault = -4, i2cTransferSwFault = -5 }
	Return codes for single master mode transfer function.

Function Documentation

◆ I2C_BusFreqGet()

uint32_t I2C_BusFreqGet ( I2C_TypeDef * i2c )

Get the current configured I2C bus frequency.

This frequency is only relevant when acting as master.

Note: The actual frequency is a real number, this function returns a rounded down (truncated) integer value.

Parameters

[in] i2c A pointer to the I2C peripheral register block.

Returns: The current I2C frequency in Hz.

◆ I2C_BusFreqSet()

void I2C_BusFreqSet	(	I2C_TypeDef *	`i2c,`
		uint32_t	`freqRef,`
		uint32_t	`freqScl,`
		I2C_ClockHLR_TypeDef	`i2cMode`
	)

Set the I2C bus frequency.

The bus frequency is only relevant when acting as master. The bus frequency should not be set higher than the maximum frequency accepted by the slowest device on the bus.

Notice that, due to asymmetric requirements on low and high I2C clock cycles in the I2C specification, the maximum frequency allowed to comply with the specification may be somewhat lower than expected.

See the reference manual, details on I2C clock generation, for maximum allowed theoretical frequencies for different modes.

Parameters

[in]	`i2c`	A pointer to the I2C peripheral register block.
[in]	`freqRef`	An I2C reference clock frequency in Hz that will be used. If set to 0, HFPERCLK / HFPERCCLK clock is used. Setting it to a higher than actual configured value has the consequence of reducing the real I2C frequency.
[in]	`freqScl`	A bus frequency to set (bus speed may be lower due to integer prescaling). Safe (according to the I2C specification) maximum frequencies for standard fast and fast+ modes are available using I2C_FREQ_ defines. (Using I2C_FREQ_ defines requires corresponding setting of `type` .) The slowest slave device on a bus must always be considered.
[in]	`i2cMode`	A clock low-to-high ratio type to use. If not using i2cClockHLRStandard, make sure all devices on the bus support the specified mode. Using a non-standard ratio is useful to achieve a higher bus clock in fast and fast+ modes.

◆ I2C_Enable()

void I2C_Enable	(	I2C_TypeDef *	`i2c,`
		bool	`enable`
	)

Enable/disable I2C.

Note: After enabling the I2C (from being disabled), the I2C is in BUSY state.

Parameters

[in]	`i2c`	A pointer to the I2C peripheral register block.
[in]	`enable`	True to enable counting, false to disable.

◆ I2C_Init()

void I2C_Init	(	I2C_TypeDef *	`i2c,`
		const I2C_Init_TypeDef *	`init`
	)

Initialize I2C.

Parameters

[in]	`i2c`	A pointer to the I2C peripheral register block.
[in]	`init`	A pointer to the I2C initialization structure.

◆ I2C_IntClear()

void I2C_IntClear	(	I2C_TypeDef *	`i2c,`
		uint32_t	`flags`
	)

inline

Clear one or more pending I2C interrupts.

Parameters

[in]	`i2c`	Pointer to I2C peripheral register block.
[in]	`flags`	Pending I2C interrupt source to clear. Use a bitwise logic OR combination of valid interrupt flags for the I2C module (I2C_IF_nnn).

◆ I2C_IntDisable()

void I2C_IntDisable	(	I2C_TypeDef *	`i2c,`
		uint32_t	`flags`
	)

inline

Disable one or more I2C interrupts.

Parameters

[in]	`i2c`	Pointer to I2C peripheral register block.
[in]	`flags`	I2C interrupt sources to disable. Use a bitwise logic OR combination of valid interrupt flags for the I2C module (I2C_IF_nnn).

◆ I2C_IntEnable()

void I2C_IntEnable	(	I2C_TypeDef *	`i2c,`
		uint32_t	`flags`
	)

inline

Enable one or more I2C 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 I2C_IntClear() prior to enabling the interrupt.

Parameters

[in]	`i2c`	Pointer to I2C peripheral register block.
[in]	`flags`	I2C interrupt sources to enable. Use a bitwise logic OR combination of valid interrupt flags for the I2C module (I2C_IF_nnn).

◆ I2C_IntGet()

uint32_t I2C_IntGet ( I2C_TypeDef * i2c )

inline

Get pending I2C interrupt flags.

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

Parameters

[in] i2c Pointer to I2C peripheral register block.

Returns: I2C interrupt sources pending. A bitwise logic OR combination of valid interrupt flags for the I2C module (I2C_IF_nnn).

◆ I2C_IntGetEnabled()

uint32_t I2C_IntGetEnabled ( I2C_TypeDef * i2c )

inline

Get enabled and pending I2C interrupt flags.

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

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

Parameters

[in] i2c Pointer to I2C peripheral register block.

Returns

Pending and enabled I2C interrupt sources Return value is the bitwise AND of

the enabled interrupt sources in I2Cn_IEN and
the pending interrupt flags I2Cn_IF

◆ I2C_IntSet()

void I2C_IntSet	(	I2C_TypeDef *	`i2c,`
		uint32_t	`flags`
	)

inline

Set one or more pending I2C interrupts from SW.

Parameters

[in]	`i2c`	Pointer to I2C peripheral register block.
[in]	`flags`	I2C interrupt sources to set to pending. Use a bitwise logic OR combination of valid interrupt flags for the I2C module (I2C_IF_nnn).

◆ I2C_Reset()

void I2C_Reset ( I2C_TypeDef * i2c )

Reset I2C to the same state that it was in after a hardware reset.

Note: The ROUTE register is NOT reset by this function to allow for centralized setup of this feature.

Parameters

[in] i2c A pointer to the I2C peripheral register block.

◆ I2C_SlaveAddressGet()

uint8_t I2C_SlaveAddressGet ( I2C_TypeDef * i2c )

inline

Get slave address used for I2C peripheral (when operating in slave mode).

For 10-bit addressing mode, the address is split in two bytes, and only the first byte setting is fetched, effectively only controlling the 2 most significant bits of the 10-bit address. Full handling of 10-bit addressing in slave mode requires additional SW handling.

Parameters

[in] i2c Pointer to I2C peripheral register block.

Returns: I2C slave address in use. The 7 most significant bits define the actual address, the least significant bit is reserved and always returned as 0.

◆ I2C_SlaveAddressSet()

void I2C_SlaveAddressSet	(	I2C_TypeDef *	`i2c,`
		uint8_t	`addr`
	)

inline

Set slave address to use for I2C peripheral (when operating in slave mode).

For 10- bit addressing mode, the address is split in two bytes, and only the first byte is set, effectively only controlling the 2 most significant bits of the 10-bit address. Full handling of 10-bit addressing in slave mode requires additional SW handling.

Parameters

[in]	`i2c`	Pointer to I2C peripheral register block.
[in]	`addr`	I2C slave address to use. The 7 most significant bits define the actual address, the least significant bit is reserved and always set to 0.

◆ I2C_SlaveAddressMaskGet()

uint8_t I2C_SlaveAddressMaskGet ( I2C_TypeDef * i2c )

inline

Get slave address mask used for I2C peripheral (when operating in slave mode).

The address mask defines how the comparator works. A bit position with value 0 means that the corresponding slave address bit is ignored during comparison (don't care). A bit position with value 1 means that the corresponding slave address bit must match.

For 10-bit addressing mode, the address is split in two bytes, and only the mask for the first address byte is fetched, effectively only controlling the 2 most significant bits of the 10-bit address.

Parameters

[in] i2c Pointer to I2C peripheral register block.

Returns: I2C slave address mask in use. The 7 most significant bits define the actual address mask, the least significant bit is reserved and always returned as 0.

◆ I2C_SlaveAddressMaskSet()

void I2C_SlaveAddressMaskSet	(	I2C_TypeDef *	`i2c,`
		uint8_t	`mask`
	)

inline

Set slave address mask used for I2C peripheral (when operating in slave mode).

The address mask defines how the comparator works. A bit position with value 0 means that the corresponding slave address bit is ignored during comparison (don't care). A bit position with value 1 means that the corresponding slave address bit must match.

For 10-bit addressing mode, the address is split in two bytes, and only the mask for the first address byte is set, effectively only controlling the 2 most significant bits of the 10-bit address.

Parameters

[in]	`i2c`	Pointer to I2C peripheral register block.
[in]	`mask`	I2C slave address mask to use. The 7 most significant bits define the actual address mask, the least significant bit is reserved and should be 0.

◆ I2C_Transfer()

I2C_TransferReturn_TypeDef I2C_Transfer ( I2C_TypeDef * i2c )

Continue an initiated I2C transfer (single master mode only).

This function is used repeatedly after a I2C_TransferInit() to complete a transfer. It may be used in polled mode as the below example shows:

         
          I2C_TransferReturn_TypeDef
         
         ret;
        
          // Do a polled transfer
         
         ret =
         
          I2C_TransferInit
         
         (I2C0, seq);
        
          while
         
         (ret ==
         
          i2cTransferInProgress
         
         )
        
         {
        
         ret =
         
          I2C_Transfer
         
         (I2C0);
        
         }

It may also be used in interrupt driven mode, where this function is invoked from the interrupt handler. Notice that, if used in interrupt mode, NVIC interrupts must be configured and enabled for the I2C bus used. I2C peripheral specific interrupts are managed by this software.

Note: Only single master mode is supported.

Parameters

[in] i2c A pointer to the I2C peripheral register block.

Returns

Returns status for an ongoing transfer.

i2cTransferInProgress - indicates that transfer not finished.
i2cTransferDone - transfer completed successfully.
otherwise some sort of error has occurred.

◆ I2C_TransferInit()

I2C_TransferReturn_TypeDef I2C_TransferInit	(	I2C_TypeDef *	`i2c,`
		I2C_TransferSeq_TypeDef *	`seq`
	)

Prepare and start an I2C transfer (single master mode only).

This function must be invoked to start an I2C transfer sequence. To complete the transfer, I2C_Transfer() must be used either in polled mode or by adding a small driver wrapper using interrupts.

Note: Only single master mode is supported.

Parameters

[in]	`i2c`	A pointer to the I2C peripheral register block.
[in]	`seq`	A pointer to the sequence structure defining the I2C transfer to take place. The referenced structure must exist until the transfer has fully completed.

Returns

Returns the status for an ongoing transfer:

i2cTransferInProgress - indicates that the transfer is not finished.
Otherwise, an error has occurred.

Macro Definition Documentation

◆ I2C_FREQ_STANDARD_MAX

#define I2C_FREQ_STANDARD_MAX 93000

Standard mode max frequency assuming using 4:4 ratio for Nlow:Nhigh.

From I2C specification: Min Tlow = 4.7us, min Thigh = 4.0us, max Trise=1.0us, max Tfall=0.3us. Since ratio is 4:4, have to use worst case value of Tlow or Thigh as base.

1/(Tlow + Thigh + 1us + 0.3us) = 1/(4.7 + 4.7 + 1.3)us = 93458Hz

Note: Due to chip characteristics, max value is somewhat reduced.

◆ I2C_FREQ_FAST_MAX

#define I2C_FREQ_FAST_MAX 392157

Fast mode max frequency assuming using 6:3 ratio for Nlow:Nhigh.

From I2C specification: Min Tlow = 1.3us, min Thigh = 0.6us, max Trise=0.3us, max Tfall=0.3us. Since ratio is 6:3, have to use worst case value of Tlow or 2xThigh as base.

1/(Tlow + Thigh + 0.3us + 0.3us) = 1/(1.3 + 0.65 + 0.6)us = 392157Hz

◆ I2C_FREQ_FASTPLUS_MAX

#define I2C_FREQ_FASTPLUS_MAX 987167

Fast mode+ max frequency assuming using 11:6 ratio for Nlow:Nhigh.

From I2C specification: Min Tlow = 0.5us, min Thigh = 0.26us, max Trise=0.12us, max Tfall=0.12us. Since ratio is 11:6, have to use worst case value of Tlow or (11/6)xThigh as base.

1/(Tlow + Thigh + 0.12us + 0.12us) = 1/(0.5 + 0.273 + 0.24)us = 987167Hz

◆ I2C_FLAG_WRITE

#define I2C_FLAG_WRITE 0x0001

Indicate plain write sequence: S+ADDR(W)+DATA0+P.

S - Start
ADDR(W) - address with W/R bit cleared
DATA0 - Data taken from buffer with index 0
P - Stop

◆ I2C_FLAG_READ

#define I2C_FLAG_READ 0x0002

Indicate plain read sequence: S+ADDR(R)+DATA0+P.

S - Start
ADDR(R) - Address with W/R bit set
DATA0 - Data read into buffer with index 0
P - Stop

◆ I2C_FLAG_WRITE_READ

#define I2C_FLAG_WRITE_READ 0x0004

Indicate combined write/read sequence: S+ADDR(W)+DATA0+Sr+ADDR(R)+DATA1+P.

S - Start
Sr - Repeated start
ADDR(W) - Address with W/R bit cleared
ADDR(R) - Address with W/R bit set
DATAn - Data written from/read into buffer with index n
P - Stop

◆ I2C_FLAG_WRITE_WRITE

#define I2C_FLAG_WRITE_WRITE 0x0008

Indicate write sequence using two buffers: S+ADDR(W)+DATA0+DATA1+P.

S - Start
ADDR(W) - Address with W/R bit cleared
DATAn - Data written from buffer with index n
P - Stop

◆ I2C_FLAG_10BIT_ADDR

#define I2C_FLAG_10BIT_ADDR 0x0010

Use 10 bit address.

◆ I2C_INIT_DEFAULT

#define I2C_INIT_DEFAULT

Value:

         {                                                                        \
        
         true,
         
          /* Enable when initialization done. */
         
         \
        
         true,
         
          /* Set to master mode. */
         
         \
        
         0,
         
          /* Use currently configured reference clock. */
         
         \
        
         I2C_FREQ_STANDARD_MAX,
         
          /* Set to standard rate assuring being */
         
         \
        
          /*                        within I2C specification. */
         
         \
        
         i2cClockHLRStandard
         
          /* Set to use 4:4 low/high duty cycle. */
         
         \
        
         }

Suggested default configuration for I2C initialization structure.

Enumeration Type Documentation

◆ I2C_ClockHLR_TypeDef

enum I2C_ClockHLR_TypeDef

Clock low to high ratio settings.

Enumerator
i2cClockHLRStandard	Ratio is 4:4.
i2cClockHLRAsymetric	Ratio is 6:3.
i2cClockHLRFast	Ratio is 11:3.

◆ I2C_TransferReturn_TypeDef

enum I2C_TransferReturn_TypeDef

Return codes for single master mode transfer function.

Enumerator
i2cTransferInProgress	Transfer in progress.
i2cTransferDone	Transfer completed successfully.
i2cTransferNack	NACK received during transfer.
i2cTransferBusErr	Bus error during transfer (misplaced START/STOP).
i2cTransferArbLost	Arbitration lost during transfer.
i2cTransferUsageFault	Usage fault.
i2cTransferSwFault	SW fault.

I2C - Inter-Integrated Circuit

Description

Data Structures

Functions

Macros

Enumerations

Function Documentation

◆ I2C_BusFreqGet()

◆ I2C_BusFreqSet()

◆ I2C_Enable()

◆ I2C_Init()

◆ I2C_IntClear()

◆ I2C_IntDisable()

◆ I2C_IntEnable()

◆ I2C_IntGet()

◆ I2C_IntGetEnabled()

◆ I2C_IntSet()

◆ I2C_Reset()

◆ I2C_SlaveAddressGet()

◆ I2C_SlaveAddressSet()

◆ I2C_SlaveAddressMaskGet()

◆ I2C_SlaveAddressMaskSet()

◆ I2C_Transfer()

◆ I2C_TransferInit()

Macro Definition Documentation

◆ I2C_FREQ_STANDARD_MAX

◆ I2C_FREQ_FAST_MAX

◆ I2C_FREQ_FASTPLUS_MAX

◆ I2C_FLAG_WRITE

◆ I2C_FLAG_READ

◆ I2C_FLAG_WRITE_READ

◆ I2C_FLAG_WRITE_WRITE

◆ I2C_FLAG_10BIT_ADDR

◆ I2C_INIT_DEFAULT

Enumeration Type Documentation

◆ I2C_ClockHLR_TypeDef

◆ I2C_TransferReturn_TypeDef