Slave's types and basic functions (header) More...

#include <stdint.h>
#include <stddef.h>
#include "base.h"

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Data Structures
struct	ModbusSlaveFunctionHandler
	Associates Modbus function ID with a pointer to a parsing function. More...

struct	ModbusRegisterCallbackArgs
	Contains arguments for the register callback function. More...

struct	ModbusRegisterCallbackResult
	Contains values returned by the slave register callback. More...

struct	ModbusSlave
	Slave device status. More...

Typedefs
typedef struct ModbusSlave	ModbusSlave

typedef ModbusErrorInfo(*	ModbusRequestParsingFunction) (ModbusSlave status, uint8_t function, const uint8_t requestPDU, uint8_t requestLength)
	A pointer to request parsing function.

typedef struct ModbusSlaveFunctionHandler	ModbusSlaveFunctionHandler
	Associates Modbus function ID with a pointer to a parsing function.

typedef enum ModbusRegisterQuery	ModbusRegisterQuery
	Determines type of request made to the register callback function.

typedef struct ModbusRegisterCallbackArgs	ModbusRegisterCallbackArgs
	Contains arguments for the register callback function.

typedef struct ModbusRegisterCallbackResult	ModbusRegisterCallbackResult
	Contains values returned by the slave register callback.

typedef ModbusError(*	ModbusRegisterCallback) (const ModbusSlave status, const ModbusRegisterCallbackArgs args, ModbusRegisterCallbackResult *out)
	A pointer to callback for performing all register operations.

typedef ModbusError(*	ModbusSlaveExceptionCallback) (const ModbusSlave *status, uint8_t function, ModbusExceptionCode code)
	A pointer to a callback called when a Modbus exception is generated (for slave)

Enumerations
enum	ModbusRegisterQuery { MODBUS_REGQ_R_CHECK , MODBUS_REGQ_W_CHECK , MODBUS_REGQ_R , MODBUS_REGQ_W }
	Determines type of request made to the register callback function. More...

Functions
	ModbusErrorInfomodbusSlaveInit (ModbusSlave status, ModbusRegisterCallback registerCallback, ModbusSlaveExceptionCallback exceptionCallback, ModbusAllocator allocator, const ModbusSlaveFunctionHandler functions, uint8_t functionCount)
	Initializes slave device.

void	modbusSlaveDestroy (ModbusSlave *status)
	Frees memory allocated in the ModbusSlave struct.

	ModbusErrorInfomodbusBuildException (ModbusSlave *status, uint8_t function, ModbusExceptionCode code)
	Builds an exception response frame.

	ModbusErrorInfomodbusBuildExceptionPDU (ModbusSlave *status, uint8_t function, ModbusExceptionCode code)
	Builds an exception PDU.

	ModbusErrorInfomodbusBuildExceptionRTU (ModbusSlave *status, uint8_t address, uint8_t function, ModbusExceptionCode code)
	Builds a Modbus RTU exception.

	ModbusErrorInfomodbusBuildExceptionTCP (ModbusSlave *status, uint16_t transactionID, uint8_t unitID, uint8_t function, ModbusExceptionCode code)
	Builds a Modbus TCP exception.

	ModbusErrorInfomodbusParseRequest (ModbusSlave status, const uint8_t request, uint8_t requestLength)
	Parses provided PDU and generates response honorinng `pduOffset` and `padding` set in ModbusSlave during response generation.

	ModbusErrorInfomodbusParseRequestPDU (ModbusSlave status, const uint8_t request, uint8_t requestLength)
	Parses provided PDU and generates PDU for the response frame.

	ModbusErrorInfomodbusParseRequestRTU (ModbusSlave status, uint8_t slaveAddress, const uint8_t request, uint16_t requestLength)
	Parses provided Modbus RTU request frame and generates a Modbus RTU response.

	ModbusErrorInfomodbusParseRequestTCP (ModbusSlave status, const uint8_t request, uint16_t requestLength)
	Parses provided Modbus TCP request frame and generates a Modbus TCP response.

static const uint8_t *	modbusSlaveGetResponse (const ModbusSlave *status)
	Returns a pointer to the response generated by the slave.

static uint16_t	modbusSlaveGetResponseLength (const ModbusSlave *status)
	Returns the length of the response generated by the slave.

static void	modbusSlaveSetUserPointer (ModbusSlave status, void ptr)
	Allows user to set the custom context pointer.

static void *	modbusSlaveGetUserPointer (const ModbusSlave *status)
	Retreieves the custom context pointer.

static ModbusError	modbusSlaveAllocateResponse (ModbusSlave *status, uint16_t pduSize)
	Allocates memory for slave's response frame.

static void	modbusSlaveFreeResponse (ModbusSlave *status)
	Frees memory allocated for slave's response frame.

Variables
ModbusSlaveFunctionHandler	modbusSlaveDefaultFunctions []
	Associates function IDs with pointers to functions responsible for parsing. Length of this array is stored in modbusSlaveDefaultFunctionCount.

const uint8_t	modbusSlaveDefaultFunctionCount
	Stores length of modbusSlaveDefaultFunctions.

Detailed Description

Slave's types and basic functions (header)

Typedef Documentation

◆ ModbusRegisterCallback

typedef ModbusError(* ModbusRegisterCallback) (const ModbusSlave *status, const ModbusRegisterCallbackArgs *args, ModbusRegisterCallbackResult *out)

A pointer to callback for performing all register operations.

See also: slave-register-callback

◆ ModbusRegisterCallbackArgs

typedef struct ModbusRegisterCallbackArgs ModbusRegisterCallbackArgs

Contains arguments for the register callback function.

◆ ModbusRegisterCallbackResult

typedef struct ModbusRegisterCallbackResult ModbusRegisterCallbackResult

Contains values returned by the slave register callback.

◆ ModbusRegisterQuery

typedef enum ModbusRegisterQuery ModbusRegisterQuery

Determines type of request made to the register callback function.

◆ ModbusRequestParsingFunction

typedef ModbusErrorInfo(* ModbusRequestParsingFunction) (ModbusSlave *status, uint8_t function, const uint8_t *requestPDU, uint8_t requestLength)

A pointer to request parsing function.

◆ ModbusSlave

typedef struct ModbusSlave ModbusSlave

◆ ModbusSlaveExceptionCallback

typedef ModbusError(* ModbusSlaveExceptionCallback) (const ModbusSlave *status, uint8_t function, ModbusExceptionCode code)

A pointer to a callback called when a Modbus exception is generated (for slave)

See also: slave-exception-callback

◆ ModbusSlaveFunctionHandler

typedef struct ModbusSlaveFunctionHandler ModbusSlaveFunctionHandler

Associates Modbus function ID with a pointer to a parsing function.

Enumeration Type Documentation

◆ ModbusRegisterQuery

enum ModbusRegisterQuery

Determines type of request made to the register callback function.

Enumerator
MODBUS_REGQ_R_CHECK	Request for read access.
MODBUS_REGQ_W_CHECK	Request for write access.
MODBUS_REGQ_R	Read request.
MODBUS_REGQ_W	Write request.

Function Documentation

◆ ModbusErrorInfomodbusBuildException()

ModbusErrorInfomodbusBuildException	(	ModbusSlave *	status,
		uint8_t	function,
		ModbusExceptionCode	code )

Builds an exception response frame.

Parameters

function	function that reported the exception
code	Modbus exception code

Returns: MODBUS_GENERAL_ERROR(ALLOC) on memory allocation failure; MODBUS_NO_ERROR() on success

Note: If set, exceptionCallback from ModbusSlave is called, even if the response frame is going to be discarded (when the request was broadcast).

Warning: This function expects ModbusSlave::response::pduOffset and ModbusSlave::response::padding to be set properly! If you're looking for a function to manually build an exception please use modbusBuildExceptionPDU(), modbusBuildExceptionRTU() or modbusBuildExceptionTCP()

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◆ ModbusErrorInfomodbusBuildExceptionPDU()

ModbusErrorInfomodbusBuildExceptionPDU	(	ModbusSlave *	status,
		uint8_t	function,
		ModbusExceptionCode	code )

Builds an exception PDU.

Parameters

function	function that reported the exception
code	Modbus exception code

Returns: MODBUS_GENERAL_ERROR(ALLOC) on memory allocation failure; MODBUS_NO_ERROR() on success

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◆ ModbusErrorInfomodbusBuildExceptionRTU()

ModbusErrorInfomodbusBuildExceptionRTU	(	ModbusSlave *	status,
		uint8_t	address,
		uint8_t	function,
		ModbusExceptionCode	code )

Builds a Modbus RTU exception.

Parameters

address	slave address to be reported in the excetion
function	function that reported the exception
code	Modbus exception code

Returns: MODBUS_GENERAL_ERROR(ADDRESS) if address is 0; MODBUS_GENERAL_ERROR(ALLOC) on memory allocation failure; MODBUS_GENERAL_ERROR(LENGTH) if the allocated response has invalid length; MODBUS_NO_ERROR() on success

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◆ ModbusErrorInfomodbusBuildExceptionTCP()

ModbusErrorInfomodbusBuildExceptionTCP	(	ModbusSlave *	status,
		uint16_t	transactionID,
		uint8_t	unitID,
		uint8_t	function,
		ModbusExceptionCode	code )

Builds a Modbus TCP exception.

Parameters

transactionID	transaction ID
unitID	unit ID to be reported in the exception
function	function that reported the exception
code	Modbus exception code

Returns: MODBUS_GENERAL_ERROR(ALLOC) on memory allocation failure; MODBUS_GENERAL_ERROR(LENGTH) if the allocated response has invalid length; MODBUS_NO_ERROR() on success

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◆ ModbusErrorInfomodbusParseRequest()

ModbusErrorInfomodbusParseRequest	(	ModbusSlave *	status,
		const uint8_t *	request,
		uint8_t	requestLength )

Parses provided PDU and generates response honorinng pduOffset and padding set in ModbusSlave during response generation.

Parameters

request	pointer to the PDU data
requestLength	length of the PDU (valid range: 1 - 253)

Returns: Any errors from parsing functions

Warning: This function expects ModbusSlave::response::pduOffset and ModbusSlave::response::padding to be set properly! If you're looking for a function to parse PDU and generate a PDU response, please use modbusParseRequestPDU() instead.; The response frame can only be accessed if modbusIsOk() called on the return value of this function evaluates to true.

◆ ModbusErrorInfomodbusParseRequestPDU()

ModbusErrorInfomodbusParseRequestPDU	(	ModbusSlave *	status,
		const uint8_t *	request,
		uint8_t	requestLength )

Parses provided PDU and generates PDU for the response frame.

Parameters

request	pointer to the PDU data
requestLength	length of the PDU (valid range: 1 - 253)

Returns: MODBUS_REQUEST_ERROR(LENGTH) if length of the frame is invalid; Any errors from parsing functions

Warning: The response frame can only be accessed if modbusIsOk() called on the return value from this function evaluates to true.; The requestLength argument is of type uint8_t and not uint16_t as in case of Modbus RTU and TCP.

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◆ ModbusErrorInfomodbusParseRequestRTU()

ModbusErrorInfomodbusParseRequestRTU	(	ModbusSlave *	status,
		uint8_t	slaveAddress,
		const uint8_t *	request,
		uint16_t	requestLength )

Parses provided Modbus RTU request frame and generates a Modbus RTU response.

Parameters

slaveAddress	ID of the slave to match with the request
request	pointer to a Modbus RTU frame
requestLength	length of the frame (valid range: 4 - 256)

Returns: MODBUS_REQUEST_ERROR(LENGTH) if length of the frame is invalid; MODBUS_REQUEST_ERROR(CRC) if CRC is invalid; MODBUS_REQUEST_ERROR(ADDRESS) if the request is meant for other slave; MODBUS_GENERAL_ERROR(LENGTH) if the resulting response frame has invalid length; Any errors from parsing functions

Warning: The response frame can only be accessed if modbusIsOk() called on the return value of this function evaluates to true.

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◆ ModbusErrorInfomodbusParseRequestTCP()

ModbusErrorInfomodbusParseRequestTCP	(	ModbusSlave *	status,
		const uint8_t *	request,
		uint16_t	requestLength )

Parses provided Modbus TCP request frame and generates a Modbus TCP response.

Parameters

request	pointer to a Modbus TCP frame
requestLength	length of the frame (valid range: 8 - 260)

Returns: MODBUS_REQUEST_ERROR(LENGTH) if length of the frame is invalid or different from the declared one; MODBUS_REQUEST_ERROR(BAD_PROTOCOL) if the frame is not a Modbus TCP message; MODBUS_GENERAL_ERROR(LENGTH) if the resulting response frame has invalid length; Any errors from parsing functions

Warning: The response frame can only be accessed if modbusIsOk() called on the return value of this function evaluates to true.

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◆ ModbusErrorInfomodbusSlaveInit()

ModbusErrorInfomodbusSlaveInit	(	ModbusSlave *	status,
		ModbusRegisterCallback	registerCallback,
		ModbusSlaveExceptionCallback	exceptionCallback,
		ModbusAllocator	allocator,
		const ModbusSlaveFunctionHandler *	functions,
		uint8_t	functionCount )

Initializes slave device.

Parameters

registerCallback	Callback function for handling all register operations (may be required by used parsing functions)
exceptionCallback	Callback function for handling slave exceptions (optional)
allocator	Memory allocator to be used (see modbusDefaultAllocator) (required)
functions	Pointer to array of supported function handlers (required). The lifetime of this array must not be shorter than the lifetime of the slave.
functionCount	Number of function handlers in the array (required)

Returns: MODBUS_NO_ERROR() on success

Warning: This function must not be called on an already initialized ModbusSlave struct.

See also: modbusDefaultAllocator(); modbusSlaveDefaultFunctions

◆ modbusSlaveAllocateResponse()

static ModbusError modbusSlaveAllocateResponse	(	ModbusSlave *	status,
		uint16_t	pduSize )

inlinestatic

Allocates memory for slave's response frame.

Parameters

pduSize size of the PDU section. 0 if the slave doesn't want to respond.

Returns: MODBUS_ERROR_ALLOC on allocation failure

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◆ modbusSlaveDestroy()

void modbusSlaveDestroy ( ModbusSlave * status )

Frees memory allocated in the ModbusSlave struct.

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◆ modbusSlaveFreeResponse()

static void modbusSlaveFreeResponse ( ModbusSlave * status )

inlinestatic

Frees memory allocated for slave's response frame.

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◆ modbusSlaveGetResponse()

static const uint8_t * modbusSlaveGetResponse ( const ModbusSlave * status )

inlinestatic

Returns a pointer to the response generated by the slave.

Note: This function can only be used if the last call to modbusParseRequest*() was successful (i.e. modbusIsOk() was true for the return value)

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◆ modbusSlaveGetResponseLength()

static uint16_t modbusSlaveGetResponseLength ( const ModbusSlave * status )

inlinestatic

Returns the length of the response generated by the slave.

Note: This function can only be used if the last call to modbusParseRequest*() was successful (i.e. modbusIsOk() was true for the return value)

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◆ modbusSlaveGetUserPointer()

static void * modbusSlaveGetUserPointer ( const ModbusSlave * status )

inlinestatic

Retreieves the custom context pointer.

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◆ modbusSlaveSetUserPointer()

static void modbusSlaveSetUserPointer	(	ModbusSlave *	status,
		void *	ptr )

inlinestatic

Allows user to set the custom context pointer.

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Variable Documentation

◆ modbusSlaveDefaultFunctionCount

const uint8_t modbusSlaveDefaultFunctionCount

extern

Stores length of modbusSlaveDefaultFunctions.

◆ modbusSlaveDefaultFunctions

ModbusSlaveFunctionHandler modbusSlaveDefaultFunctions[]

extern

Associates function IDs with pointers to functions responsible for parsing. Length of this array is stored in modbusSlaveDefaultFunctionCount.

Note: Contents depend on defined LIGHTMODBUS_FxxS macros!

Data Structures

Typedefs

Enumerations

Functions

Variables

Detailed Description

Typedef Documentation

◆ ModbusRegisterCallback

◆ ModbusRegisterCallbackArgs

◆ ModbusRegisterCallbackResult

◆ ModbusRegisterQuery

◆ ModbusRequestParsingFunction

◆ ModbusSlave

◆ ModbusSlaveExceptionCallback

◆ ModbusSlaveFunctionHandler

Enumeration Type Documentation

◆ ModbusRegisterQuery

Function Documentation

◆ ModbusErrorInfomodbusBuildException()

◆ ModbusErrorInfomodbusBuildExceptionPDU()

◆ ModbusErrorInfomodbusBuildExceptionRTU()

◆ ModbusErrorInfomodbusBuildExceptionTCP()

◆ ModbusErrorInfomodbusParseRequest()

◆ ModbusErrorInfomodbusParseRequestPDU()

◆ ModbusErrorInfomodbusParseRequestRTU()

◆ ModbusErrorInfomodbusParseRequestTCP()

◆ ModbusErrorInfomodbusSlaveInit()

◆ modbusSlaveAllocateResponse()

◆ modbusSlaveDestroy()

◆ modbusSlaveFreeResponse()

◆ modbusSlaveGetResponse()

◆ modbusSlaveGetResponseLength()

◆ modbusSlaveGetUserPointer()

◆ modbusSlaveSetUserPointer()

Variable Documentation

◆ modbusSlaveDefaultFunctionCount

◆ modbusSlaveDefaultFunctions