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

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

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

struct	ModbusDataCallbackArgs
	Arguments for the data callback. More...

struct	ModbusMaster
	Master device status. More...

Typedefs
typedef struct ModbusMaster	ModbusMaster

typedef ModbusErrorInfo(*	ModbusResponseParsingFunction) (ModbusMaster status, uint8_t address, uint8_t function, const uint8_t requestPDU, uint8_t requestLength, const uint8_t *responsePDU, uint8_t responseLength)
	A pointer to a response parsing function.

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

typedef struct ModbusDataCallbackArgs	ModbusDataCallbackArgs
	Arguments for the data callback.

typedef ModbusError(*	ModbusDataCallback) (const ModbusMaster status, const ModbusDataCallbackArgs args)
	A pointer to a callback used for handling data incoming to master.

typedef ModbusError(*	ModbusMasterExceptionCallback) (const ModbusMaster *status, uint8_t address, uint8_t function, ModbusExceptionCode code)
	A pointer to a callback called when a Modbus exception is generated (for master)

Functions
ModbusErrorInfo	modbusMasterInit (ModbusMaster status, ModbusDataCallback dataCallback, ModbusMasterExceptionCallback exceptionCallback, ModbusAllocator allocator, const ModbusMasterFunctionHandler functions, uint8_t functionCount)
	Initializes a ModbusMaster struct.

void	modbusMasterDestroy (ModbusMaster *status)
	Deinitializes a ModbusMaster struct.

ModbusErrorInfo	modbusBeginRequestPDU (ModbusMaster *status)
	Begins a PDU-only request.

ModbusErrorInfo	modbusEndRequestPDU (ModbusMaster *status)
	Finalizes a PDU-only request.

ModbusErrorInfo	modbusBeginRequestRTU (ModbusMaster *status)
	Begins a RTU request.

ModbusErrorInfo	modbusEndRequestRTU (ModbusMaster *status, uint8_t address)
	Finalizes a Modbus RTU request.

ModbusErrorInfo	modbusBeginRequestTCP (ModbusMaster *status)
	Begins a TCP request.

ModbusErrorInfo	modbusEndRequestTCP (ModbusMaster *status, uint16_t transaction, uint8_t unit)
	Finalizes a Modbus TCP request.

ModbusErrorInfo	modbusParseResponsePDU (ModbusMaster status, uint8_t address, const uint8_t request, uint8_t requestLength, const uint8_t *response, uint8_t responseLength)
	Parses a PDU section of a slave response.

ModbusErrorInfo	modbusParseResponseRTU (ModbusMaster status, const uint8_t request, uint16_t requestLength, const uint8_t *response, uint16_t responseLength)
	Parses a Modbus RTU slave response.

ModbusErrorInfo	modbusParseResponseTCP (ModbusMaster status, const uint8_t request, uint16_t requestLength, const uint8_t *response, uint16_t responseLength)
	Parses a Modbus TCP slave response.

static const uint8_t *	modbusMasterGetRequest (const ModbusMaster *status)
	Returns a pointer to the request generated by the master.

static uint16_t	modbusMasterGetRequestLength (const ModbusMaster *status)
	Returns the length of the request generated by the master.

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

static void *	modbusMasterGetUserPointer (const ModbusMaster *status)
	Retreieves the custom context pointer.

static ModbusError	modbusMasterAllocateRequest (ModbusMaster *status, uint16_t pduSize)
	Allocates memory for the request frame.

static void	modbusMasterFreeRequest (ModbusMaster *status)
	Frees memory allocated for master's request frame.

Variables
ModbusMasterFunctionHandler	modbusMasterDefaultFunctions []
	Default array of supported functions. Length is stored in modbusMasterDefaultFunctionCount.

const uint8_t	modbusMasterDefaultFunctionCount
	Stores length of modbusMasterDefaultFunctions array.

Detailed Description

Master's types and basic functions (header)

Typedef Documentation

◆ ModbusDataCallback

typedef ModbusError(* ModbusDataCallback) (const ModbusMaster *status, const ModbusDataCallbackArgs *args)

A pointer to a callback used for handling data incoming to master.

See also: master-data-callback

◆ ModbusDataCallbackArgs

typedef struct ModbusDataCallbackArgs ModbusDataCallbackArgs

Arguments for the data callback.

◆ ModbusMaster

typedef struct ModbusMaster ModbusMaster

◆ ModbusMasterExceptionCallback

typedef ModbusError(* ModbusMasterExceptionCallback) (const ModbusMaster *status, uint8_t address, uint8_t function, ModbusExceptionCode code)

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

See also: master-exception-callback

◆ ModbusMasterFunctionHandler

typedef struct ModbusMasterFunctionHandler ModbusMasterFunctionHandler

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

◆ ModbusResponseParsingFunction

typedef ModbusErrorInfo(* ModbusResponseParsingFunction) (ModbusMaster *status, uint8_t address, uint8_t function, const uint8_t *requestPDU, uint8_t requestLength, const uint8_t *responsePDU, uint8_t responseLength)

A pointer to a response parsing function.

Function Documentation

◆ modbusBeginRequestPDU()

ModbusErrorInfo modbusBeginRequestPDU ( ModbusMaster * status )

Begins a PDU-only request.

Returns: MODBUS_NO_ERROR()

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◆ modbusBeginRequestRTU()

ModbusErrorInfo modbusBeginRequestRTU ( ModbusMaster * status )

Begins a RTU request.

Returns: MODBUS_NO_ERROR()

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◆ modbusBeginRequestTCP()

ModbusErrorInfo modbusBeginRequestTCP ( ModbusMaster * status )

Begins a TCP request.

Returns: MODBUS_NO_ERROR()

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◆ modbusEndRequestPDU()

ModbusErrorInfo modbusEndRequestPDU ( ModbusMaster * status )

Finalizes a PDU-only request.

Returns: MODBUS_NO_ERROR()

◆ modbusEndRequestRTU()

ModbusErrorInfo modbusEndRequestRTU	(	ModbusMaster *	status,
		uint8_t	address
	)

Finalizes a Modbus RTU request.

Returns: MODBUS_GENERAL_ERROR(LENGTH) if the allocated frame has invalid length; MODBUS_NO_ERROR() on success

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◆ modbusEndRequestTCP()

ModbusErrorInfo modbusEndRequestTCP	(	ModbusMaster *	status,
		uint16_t	transactionID,
		uint8_t	unitID
	)

Finalizes a Modbus TCP request.

Parameters

transactionID	Modbus TCP transaction identifier
unitID	Modbus TCP Unit ID

Returns: MODBUS_GENERAL_ERROR(LENGTH) if the allocated frame has invalid length; MODBUS_NO_ERROR() on success

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◆ modbusMasterAllocateRequest()

static ModbusError modbusMasterAllocateRequest	(	ModbusMaster *	status,
		uint16_t	pduSize
	)

inlinestatic

Allocates memory for the request frame.

Parameters

pduSize size of the PDU section of the frame. 0 implies no request at all.

Returns: MODBUS_ERROR_ALLOC on allocation failure

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◆ modbusMasterDestroy()

void modbusMasterDestroy ( ModbusMaster * status )

Deinitializes a ModbusMaster struct.

Parameters

status ModbusMaster struct to be destroyed

Note: This does not free the memory pointed to by the status pointer and only cleans up the interals ofthe ModbusMaster struct.

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◆ modbusMasterFreeRequest()

static void modbusMasterFreeRequest ( ModbusMaster * status )

inlinestatic

Frees memory allocated for master's request frame.

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◆ modbusMasterGetRequest()

static const uint8_t * modbusMasterGetRequest ( const ModbusMaster * status )

inlinestatic

Returns a pointer to the request generated by the master.

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◆ modbusMasterGetRequestLength()

static uint16_t modbusMasterGetRequestLength ( const ModbusMaster * status )

inlinestatic

Returns the length of the request generated by the master.

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◆ modbusMasterGetUserPointer()

static void * modbusMasterGetUserPointer ( const ModbusMaster * status )

inlinestatic

Retreieves the custom context pointer.

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◆ modbusMasterInit()

ModbusErrorInfo modbusMasterInit	(	ModbusMaster *	status,
		ModbusDataCallback	dataCallback,
		ModbusMasterExceptionCallback	exceptionCallback,
		ModbusAllocator	allocator,
		const ModbusMasterFunctionHandler *	functions,
		uint8_t	functionCount
	)

Initializes a ModbusMaster struct.

Parameters

status	ModbusMaster struct to be initialized
dataCallback	Callback function for handling incoming data (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 an array of supported function handlers (required). The lifetime of this array must not be shorter than the lifetime of the master.
functionCount	Number of elements in the `functions` array (required)

Returns: MODBUS_NO_ERROR() on success

See also: modbusDefaultAllocator(); modbusMasterDefaultFunctions

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◆ modbusMasterSetUserPointer()

static void modbusMasterSetUserPointer	(	ModbusMaster *	status,
		void *	ptr
	)

inlinestatic

Allows user to set the custom context pointer.

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◆ modbusParseResponsePDU()

ModbusErrorInfo modbusParseResponsePDU	(	ModbusMaster *	status,
		uint8_t	address,
		const uint8_t *	request,
		uint8_t	requestLength,
		const uint8_t *	response,
		uint8_t	responseLength
	)

Parses a PDU section of a slave response.

Parameters

address	Value to be reported as slave address
request	Pointer to the PDU section of the request frame
requestLength	Length of the request PDU (valid range: 1 - 253)
response	Pointer to the PDU section of the response
responseLength	Length of the response PDU (valid range: 1 - 253)

Returns: MODBUS_REQUEST_ERROR(LENGTH) if the request has invalid length; MODBUS_RESPONSE_ERROR(LENGTH) if the response has invalid length; MODBUS_RESPONSE_ERROR(FUNCTION) if the function code in request doesn't match the one in response; MODBUS_GENERAL_ERROR(FUNCTION) if the function code is not supported; Result from the parsing function on success (modbusParseRequest*() functions)

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◆ modbusParseResponseRTU()

ModbusErrorInfo modbusParseResponseRTU	(	ModbusMaster *	status,
		const uint8_t *	request,
		uint16_t	requestLength,
		const uint8_t *	response,
		uint16_t	responseLength
	)

Parses a Modbus RTU slave response.

Parameters

request	Pointer to the request frame
requestLength	Length of the request (valid range: 4 - 256)
response	Pointer to the response frame
responseLength	Length of the response (valid range: 4 - 256)

Returns: MODBUS_REQUEST_ERROR(LENGTH) if the request has invalid length; MODBUS_RESPONSE_ERROR(LENGTH) if the response has invalid length; MODBUS_REQUEST_ERROR(CRC) if the request CRC is invalid; MODBUS_RESPONSE_ERROR(CRC) if the response CRC is invalid; MODBUS_RESPONSE_ERROR(ADDRESS) if the address is 0 or if request/response addressess don't match; Result of modbusParseResponsePDU() otherwise

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◆ modbusParseResponseTCP()

ModbusErrorInfo modbusParseResponseTCP	(	ModbusMaster *	status,
		const uint8_t *	request,
		uint16_t	requestLength,
		const uint8_t *	response,
		uint16_t	responseLength
	)

Parses a Modbus TCP slave response.

Parameters

request	Pointer to the request frame
requestLength	Length of the request (valid range: 8 - 260)
response	Pointer to the response frame
responseLength	Length of the response (valid range: 8 - 260)

Returns: MODBUS_REQUEST_ERROR(LENGTH) if the request has invalid length or if the request frame has different from declared one; MODBUS_RESPONSE_ERROR(LENGTH) if the response has invalid length or if the response frame has different from declared one; MODBUS_REQUEST_ERROR(BAD_PROTOCOL) if the protocol ID in request is not 0; MODBUS_RESPONSE_ERROR(BAD_PROTOCOL) if the protocol ID in response is not 0; MODBUS_RESPONSE_ERROR(BAD_TRANSACTION) if the transaction ID in request is not the same as in response; MODBUS_RESPONSE_ERROR(ADDRESS) if the address in response is not the same as in request; Result of modbusParseResponsePDU() otherwise

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Variable Documentation

◆ modbusMasterDefaultFunctionCount

const uint8_t modbusMasterDefaultFunctionCount

extern

Stores length of modbusMasterDefaultFunctions array.

◆ modbusMasterDefaultFunctions

ModbusMasterFunctionHandler modbusMasterDefaultFunctions[]

extern

Default array of supported functions. Length is stored in modbusMasterDefaultFunctionCount.

Contents are controlled by defining LIGHTMODBUS_FxxM macros.

Data Structures

Typedefs

Functions

Variables

Detailed Description

Typedef Documentation

◆ ModbusDataCallback

◆ ModbusDataCallbackArgs

◆ ModbusMaster

◆ ModbusMasterExceptionCallback

◆ ModbusMasterFunctionHandler

◆ ModbusResponseParsingFunction

Function Documentation

◆ modbusBeginRequestPDU()

◆ modbusBeginRequestRTU()

◆ modbusBeginRequestTCP()

◆ modbusEndRequestPDU()

◆ modbusEndRequestRTU()

◆ modbusEndRequestTCP()

◆ modbusMasterAllocateRequest()

◆ modbusMasterDestroy()

◆ modbusMasterFreeRequest()

◆ modbusMasterGetRequest()

◆ modbusMasterGetRequestLength()

◆ modbusMasterGetUserPointer()

◆ modbusMasterInit()

◆ modbusMasterSetUserPointer()

◆ modbusParseResponsePDU()

◆ modbusParseResponseRTU()

◆ modbusParseResponseTCP()

Variable Documentation

◆ modbusMasterDefaultFunctionCount

◆ modbusMasterDefaultFunctions