Modbus communication interface. More...

Classes
struct	MYRIOTA_ModbusSerialInterface

struct	MYRIOTA_ModbusInitOptions

Typedefs
typedef uint8_t	MYRIOTA_ModbusHandle

typedef uint8_t	MYRIOTA_ModbusDeviceAddress

typedef uint16_t	MYRIOTA_ModbusDataAddress

typedef int(*	MYRIOTA_ModbusSerialInterfaceInitFn_t) (void *const ctx)

typedef void(*	MYRIOTA_ModbusSerialInterfaceDeinitFn_t) (void *const ctx)

typedef ssize_t(*	MYRIOTA_ModbusSerialInterfaceReadFn_t) (void const ctx, uint8_t const buffer, const size_t count)

typedef ssize_t(*	MYRIOTA_ModbusSerialInterfaceWriteFn_t) (void const ctx, const uint8_t const buffer, const size_t count)

Enumerations
enum	MYRIOTA_ModbusErrors { MODBUS_SUCCESS = 0 , MODBUS_ERROR_EXCEPTION_ILLEGAL_FUNCTION = 0x01 , MODBUS_ERROR_EXCEPTION_ILLEGAL_DATA_ADDRESS = 0x02 , MODBUS_ERROR_EXCEPTION_ILLEGAL_DATA_VALUE = 0x03 , MODBUS_ERROR_EXCEPTION_SLAVE_DEVICE_FAILURE = 0x04 , MODBUS_ERROR_EXCEPTION_ACKNOWLEDGE = 0x05 , MODBUS_ERROR_EXCEPTION_SLAVE_DEVICE_BUSY = 0x06 , MODBUS_ERROR_EXCEPTION_NEGATIVE_ACKNOWLEDGMENT = 0x07 , MODBUS_ERROR_EXCEPTION_MEMORY_PARITY_ERROR = 0x08 , MODBUS_ERROR_EXCEPTION_GATEWAY_PATH_UNAVAILABLE = 0x0A , MODBUS_ERROR_EXCEPTION_GATEWAY_TARGET_DEVICE_FAILED_TO_RESPOND = 0x0B , MODBUS_ERROR_INVALID_HANDLE , MODBUS_ERROR_INVALID_CRC16 , MODBUS_ERROR_MALFORMED_RESPONSE , MODBUS_ERROR_RESPONSE_FROM_WRONG_SLAVE_ADDRESS , MODBUS_ERROR_IO_FAILURE , MODBUS_ERROR_BAD_STATE , MODBUS_ERROR_OVERFLOW }

enum	MYRIOTA_ModbusFramingMode { MODBUS_FRAMING_MODE_RTU }

Functions
MYRIOTA_ModbusHandle	MYRIOTA_ModbusInit (const MYRIOTA_ModbusInitOptions options)

void	MYRIOTA_ModbusDeinit (const MYRIOTA_ModbusHandle handle)

int	MYRIOTA_ModbusEnable (const MYRIOTA_ModbusHandle handle)

int	MYRIOTA_ModbusDisable (const MYRIOTA_ModbusHandle handle)

void	MYRIOTA_ModbusBytesSetBit (uint8_t *const bytes, const size_t count, const uint8_t bit_index, const bool value)

void	MYRIOTA_ModbusBytesGetBit (const uint8_t const bytes, const size_t count, const uint8_t bit_index, bool const value)

int	MYRIOTA_ModbusReadCoils (const MYRIOTA_ModbusHandle handle, const MYRIOTA_ModbusDeviceAddress slave, const MYRIOTA_ModbusDataAddress addr, const size_t count, uint8_t *const bytes)

int	MYRIOTA_ModbusReadDiscreteInputs (const MYRIOTA_ModbusHandle handle, const MYRIOTA_ModbusDeviceAddress slave, const MYRIOTA_ModbusDataAddress addr, const size_t count, uint8_t *const bytes)

int	MYRIOTA_ModbusReadHoldingRegisters (const MYRIOTA_ModbusHandle handle, const MYRIOTA_ModbusDeviceAddress slave, const MYRIOTA_ModbusDataAddress addr, const size_t count, uint8_t *const bytes)

int	MYRIOTA_ModbusReadInputRegisters (const MYRIOTA_ModbusHandle handle, const MYRIOTA_ModbusDeviceAddress slave, const MYRIOTA_ModbusDataAddress addr, const size_t count, uint8_t *const bytes)

int	MYRIOTA_ModbusWriteCoil (const MYRIOTA_ModbusHandle handle, const MYRIOTA_ModbusDeviceAddress slave, const MYRIOTA_ModbusDataAddress addr, const uint16_t word)

int	MYRIOTA_ModbusWriteHoldingRegister (const MYRIOTA_ModbusHandle handle, const MYRIOTA_ModbusDeviceAddress slave, const MYRIOTA_ModbusDataAddress addr, const uint16_t word)

int	MYRIOTA_ModbusWriteCoils (const MYRIOTA_ModbusHandle handle, const MYRIOTA_ModbusDeviceAddress slave, const MYRIOTA_ModbusDataAddress addr, const size_t count, const uint8_t *const bytes)

int	MYRIOTA_ModbusWriteHoldingRegisters (const MYRIOTA_ModbusHandle handle, const MYRIOTA_ModbusDeviceAddress slave, const MYRIOTA_ModbusDataAddress addr, const size_t count, const uint8_t *const bytes)

Detailed Description

Modbus communication interface.

Typedef Documentation

◆ MYRIOTA_ModbusHandle

typedef uint8_t MYRIOTA_ModbusHandle

Modbus driver instance handle type.

◆ MYRIOTA_ModbusDeviceAddress

typedef uint8_t MYRIOTA_ModbusDeviceAddress

Modbus device address type.

◆ MYRIOTA_ModbusDataAddress

typedef uint16_t MYRIOTA_ModbusDataAddress

Modbus data (i.e. coils/registers) address type.

◆ MYRIOTA_ModbusSerialInterfaceInitFn_t

typedef int(* MYRIOTA_ModbusSerialInterfaceInitFn_t) (void *const ctx)

Initialization function for the serial interface used by Modbus driver.

Parameters

[in,out] ctx The user defined data context used by the serial interface.

Returns: 0 on success else < 0 on error.

◆ MYRIOTA_ModbusSerialInterfaceDeinitFn_t

typedef void(* MYRIOTA_ModbusSerialInterfaceDeinitFn_t) (void *const ctx)

De-initialization function for the serial interface used by Modbus driver.

Parameters

[in,out] ctx The user defined data context used by the serial interface.

Returns: the number of bytes written on success else < 0 on error.

◆ MYRIOTA_ModbusSerialInterfaceReadFn_t

typedef ssize_t(* MYRIOTA_ModbusSerialInterfaceReadFn_t) (void *const ctx, uint8_t *const buffer, const size_t count)

Read function for the serial interface used by Modbus driver.

Parameters

[in,out]	ctx	The user defined data context used by the serial interface.
[out]	buffer	The buffer for filling with bytes read by the serial device.
[in]	count	The total size of the buffer in bytes.

Returns: the number of bytes read on success, else < 0 on error.

◆ MYRIOTA_ModbusSerialInterfaceWriteFn_t

typedef ssize_t(* MYRIOTA_ModbusSerialInterfaceWriteFn_t) (void *const ctx, const uint8_t *const buffer, const size_t count)

Write function for the serial interface used by Modbus driver.

Parameters

[in,out]	ctx	The user defined data context used by the serial interface.
[out]	buffer	The buffer of bytes to write to the serial device.
[in]	count	The number of bytes to write from the buffer.

Returns: the number of bytes written on success, else < 0 on error.

Enumeration Type Documentation

◆ MYRIOTA_ModbusErrors

enum MYRIOTA_ModbusErrors

Error and exception codes for the modbus driver.

◆ MYRIOTA_ModbusFramingMode

enum MYRIOTA_ModbusFramingMode

The framing mode to be used by the Modbus driver.

Note: Only RTU framing is supported at the moment, but ASCII framing will be added in the future.

Enumerator
MODBUS_FRAMING_MODE_RTU	RTU (Remote Transmission Unit) Framing

Function Documentation

◆ MYRIOTA_ModbusInit()

MYRIOTA_ModbusHandle MYRIOTA_ModbusInit ( const MYRIOTA_ModbusInitOptions options )

Initializes a Modbus driver instance.

Parameters

[in] options The driver options to initialise with.

Returns: a Modus handle > 0 on success else <= 0 on error.

◆ MYRIOTA_ModbusDeinit()

void MYRIOTA_ModbusDeinit ( const MYRIOTA_ModbusHandle handle )

De-initializes a Modbus driver instance.

Parameters

[in] handle The handle for the Modbus driver to de-initialize.

◆ MYRIOTA_ModbusEnable()

int MYRIOTA_ModbusEnable ( const MYRIOTA_ModbusHandle handle )

Enables the Modbus driver.

Note: Disabling the modbus driver helps to preserve device power.

Parameters

[in] handle The handle for the Modbus driver to enable.

Returns: a Modus handle > 0 on success else <= 0 on error.

◆ MYRIOTA_ModbusDisable()

int MYRIOTA_ModbusDisable ( const MYRIOTA_ModbusHandle handle )

Disable the Modbus driver.

Note: Disabling the modbus driver helps to preserve device power.

Parameters

[in] handle The handle for the Modbus driver to disable.

Returns: a Modus handle > 0 on success else <= 0 on error.

◆ MYRIOTA_ModbusBytesSetBit()

void MYRIOTA_ModbusBytesSetBit	(	uint8_t *const	bytes,
		const size_t	count,
		const uint8_t	bit_index,
		const bool	value )

Given a buffer of bytes packed using Modbus's byte format set the value of the bit at the given index.

Note: In this context bit_index can be interpreted as the (coil_address - coil_start_address) where coil_start_address is bit_index zero.

Parameters

[out]	bytes	A buffer of bytes using Modbus's byte packing format.
[in]	count	The size of the buffer must be at least 1
[in]	bit_index	The index of the bit you would like to set, where 0 =< index < (count / 8).
[in]	value	The boolean value of the bit where 1 = true and 0 = false.

◆ MYRIOTA_ModbusBytesGetBit()

void MYRIOTA_ModbusBytesGetBit	(	const uint8_t *const	bytes,
		const size_t	count,
		const uint8_t	bit_index,
		bool *const	value )

Given a buffer of bytes packed using Modbus's byte format get the value of the bit at the given index.

Note: In this context bit_index can be interpreted as the (coil_address - coil_start_address) where coil_start_address is bit_index zero.

Parameters

[in]	bytes	A buffer of bytes using Modbus's byte packing format.
[in]	count	The size of the buffer must be at least 1
[in]	bit_index	The index of the bit you would like to set, where 0 =< index < (count / 8).
[out]	value	The boolean value of the bit where 1 = true and 0 = false.

◆ MYRIOTA_ModbusReadCoils()

int MYRIOTA_ModbusReadCoils	(	const MYRIOTA_ModbusHandle	handle,
		const MYRIOTA_ModbusDeviceAddress	slave,
		const MYRIOTA_ModbusDataAddress	addr,
		const size_t	count,
		uint8_t *const	bytes )

Read the values of a list of consecutive coils.

Parameters

[in]	handle	The handle for the Modbus driver to read from.
[in]	slave	The address of the slave device to read from.
[in]	addr	The start address of the coils to read from.
[in]	count	The number of coils to read.
[out]	bytes	The buffer to fill with the values of the coils where the size of the buffer must = ceil((count / 8)). (NOTE: Shall be in Modbus MSB bit packed format)

Returns: 0 on success else < 0 on error.

◆ MYRIOTA_ModbusReadDiscreteInputs()

int MYRIOTA_ModbusReadDiscreteInputs	(	const MYRIOTA_ModbusHandle	handle,
		const MYRIOTA_ModbusDeviceAddress	slave,
		const MYRIOTA_ModbusDataAddress	addr,
		const size_t	count,
		uint8_t *const	bytes )

Read the values of a list of consecutive discrete inputs.

Parameters

[in]	handle	The handle for the Modbus driver to read from.
[in]	slave	The address of the slave device to read from.
[in]	addr	The start address of the discrete inputs to read from.
[in]	count	The number of discrete inputs to read.
[out]	bytes	The buffer to fill with the values of the discrete inputs where the size of the buffer must = ceil((count / 8)). (NOTE: Shall be in Modbus MSB bit packed format)

Returns: 0 on success else < 0 on error

◆ MYRIOTA_ModbusReadHoldingRegisters()

int MYRIOTA_ModbusReadHoldingRegisters	(	const MYRIOTA_ModbusHandle	handle,
		const MYRIOTA_ModbusDeviceAddress	slave,
		const MYRIOTA_ModbusDataAddress	addr,
		const size_t	count,
		uint8_t *const	bytes )

Read the values of a list of consecutive holding registers.

Parameters

[in]	handle	The handle for the Modbus driver to read from.
[in]	slave	The address of the slave device to read from.
[in]	addr	The start address of the holding registers to read from.
[in]	count	The number of holding registers to read.
[out]	bytes	The buffer to fill with the values of the holding registers, where the size of the buffer must = count * 2.

Returns: 0 on success else < 0 on error.

◆ MYRIOTA_ModbusReadInputRegisters()

int MYRIOTA_ModbusReadInputRegisters	(	const MYRIOTA_ModbusHandle	handle,
		const MYRIOTA_ModbusDeviceAddress	slave,
		const MYRIOTA_ModbusDataAddress	addr,
		const size_t	count,
		uint8_t *const	bytes )

Read the values of a list of consecutive input registers.

Parameters

[in]	handle	The handle for the Modbus driver to read from.
[in]	slave	The address of the slave device to read from.
[in]	addr	The start address of the holding registers to read from.
[in]	count	The number of holding registers to read.
[out]	bytes	The buffer to fill with the values of the input registers, where the size of the buffer must = count * 2.

Returns: 0 on success else < 0 on error.

◆ MYRIOTA_ModbusWriteCoil()

int MYRIOTA_ModbusWriteCoil	(	const MYRIOTA_ModbusHandle	handle,
		const MYRIOTA_ModbusDeviceAddress	slave,
		const MYRIOTA_ModbusDataAddress	addr,
		const uint16_t	word )

Write a value to a coil.

Parameters

[in]	handle	The handle for the Modbus driver to write to.
[in]	slave	The address of the slave device to write to.
[in]	addr	The address of the coils to write to.
[in]	word	The word to write to the coil, where word must be either 0x00FF = 1 or 0x0000 = 0 (NOTE: These values are the Modbus MSB packed format).

Returns: 0 on success else < 0 on error.

◆ MYRIOTA_ModbusWriteHoldingRegister()

int MYRIOTA_ModbusWriteHoldingRegister	(	const MYRIOTA_ModbusHandle	handle,
		const MYRIOTA_ModbusDeviceAddress	slave,
		const MYRIOTA_ModbusDataAddress	addr,
		const uint16_t	word )

Write a value to a holding register.

Parameters

[in]	handle	The handle for the Modbus driver to write to.
[in]	slave	The address of the slave device to write to.
[in]	addr	The address of the holding registers to write to.
[in]	word	The word to write to the holding registers.

Returns: 0 on success else < 0 on error.

◆ MYRIOTA_ModbusWriteCoils()

int MYRIOTA_ModbusWriteCoils	(	const MYRIOTA_ModbusHandle	handle,
		const MYRIOTA_ModbusDeviceAddress	slave,
		const MYRIOTA_ModbusDataAddress	addr,
		const size_t	count,
		const uint8_t *const	bytes )

Writes values to a list of consecutive coils.

Parameters

[in]	handle	The handle for the Modbus driver to write from.
[in]	slave	The address of the slave device to write from.
[in]	addr	The start address of the coils to write from.
[in]	count	The number of coils to write.
[in]	bytes	The buffer to fill with the values of the coils where the size of the buffer must = ceil((count / 8)). (NOTE: Must be in Modbus MSB bit packed format)

Returns: 0 on success else < 0 on error.

◆ MYRIOTA_ModbusWriteHoldingRegisters()

int MYRIOTA_ModbusWriteHoldingRegisters	(	const MYRIOTA_ModbusHandle	handle,
		const MYRIOTA_ModbusDeviceAddress	slave,
		const MYRIOTA_ModbusDataAddress	addr,
		const size_t	count,
		const uint8_t *const	bytes )

Write values to a list of consecutive holding registers.

Parameters

[in]	handle	The handle for the Modbus driver to write from.
[in]	slave	The address of the slave device to write from.
[in]	addr	The start address of the input registers to write from.
[in]	count	The number of input registers to write.
[in]	bytes	The buffer to fill with the values of the holding registers where the size of the buffer must = count * 2.

Returns: 0 on success else < 0 on error.

Classes

Typedefs

Enumerations

Functions

Detailed Description

Typedef Documentation

◆ MYRIOTA_ModbusHandle

◆ MYRIOTA_ModbusDeviceAddress

◆ MYRIOTA_ModbusDataAddress

◆ MYRIOTA_ModbusSerialInterfaceInitFn_t

◆ MYRIOTA_ModbusSerialInterfaceDeinitFn_t

◆ MYRIOTA_ModbusSerialInterfaceReadFn_t

◆ MYRIOTA_ModbusSerialInterfaceWriteFn_t

Enumeration Type Documentation

◆ MYRIOTA_ModbusErrors

◆ MYRIOTA_ModbusFramingMode

Function Documentation

◆ MYRIOTA_ModbusInit()

◆ MYRIOTA_ModbusDeinit()

◆ MYRIOTA_ModbusEnable()

◆ MYRIOTA_ModbusDisable()

◆ MYRIOTA_ModbusBytesSetBit()

◆ MYRIOTA_ModbusBytesGetBit()

◆ MYRIOTA_ModbusReadCoils()

◆ MYRIOTA_ModbusReadDiscreteInputs()

◆ MYRIOTA_ModbusReadHoldingRegisters()

◆ MYRIOTA_ModbusReadInputRegisters()

◆ MYRIOTA_ModbusWriteCoil()

◆ MYRIOTA_ModbusWriteHoldingRegister()

◆ MYRIOTA_ModbusWriteCoils()

◆ MYRIOTA_ModbusWriteHoldingRegisters()