modbus.c File Reference

#include "modbus.h"
#include "crc.h"

Go to the source code of this file.

Macros
#define	READ_INPUT_REGISTERS   0x04
	Modbus function for read input register = 04.
#define	READ_HOLDING_REGISTERS   0x03
	Modbus function for read holding register = 03.
#define	WRITE_SINGLE_REGISTER   0x06
	Modbus function for write a single register = 06.
#define	ILLEGAL_FUNCTION   1
#define	ILLEGAL_DATA_ADDRESS   2
#define	ILLEGAL_DATA_VALUE   3
#define	SLAVE_DEVICE_FAILURE   4

Functions
void	modbus_timer (void)
uint16_t	measure_voltage ()
uint8_t	modbus_analyse_and_answer (void)
void	modbus_char_recvd (void)
void	modbus_send (uint8_t length)
void	modbus_init (uint8_t address)

Variables
uint8_t	modbusAddress
uint16_t	input_registers [2]
uint16_t	holding_registers [2]
uint8_t	rx_buf [256]
uint8_t	tx_buf [256]
uint8_t	recPtr = 0

Macro Definition Documentation

ILLEGAL_DATA_ADDRESS

#define ILLEGAL_DATA_ADDRESS   2

Definition at line 19 of file modbus.c.

ILLEGAL_DATA_VALUE

#define ILLEGAL_DATA_VALUE   3

Definition at line 20 of file modbus.c.

ILLEGAL_FUNCTION

#define ILLEGAL_FUNCTION   1

Definition at line 18 of file modbus.c.

READ_HOLDING_REGISTERS

#define READ_HOLDING_REGISTERS   0x03

Modbus function for read holding register = 03.

Definition at line 8 of file modbus.c.

READ_INPUT_REGISTERS

#define READ_INPUT_REGISTERS   0x04

Modbus function for read input register = 04.

Definition at line 7 of file modbus.c.

SLAVE_DEVICE_FAILURE

#define SLAVE_DEVICE_FAILURE   4

Definition at line 21 of file modbus.c.

WRITE_SINGLE_REGISTER

#define WRITE_SINGLE_REGISTER   0x06

Modbus function for write a single register = 06.

Definition at line 9 of file modbus.c.

Function Documentation

measure_voltage()

uint16_t measure_voltage

(

)

Measure the voltage on the channel for the current. This function is expected to do some filtering.

Returns

The offset

Definition at line 37 of file measure.c.

modbus_analyse_and_answer()

uint8_t modbus_analyse_and_answer

(

void

)

Analyses the received frame and answer to server

Returns

an error code if frame not valid

Definition at line 40 of file modbus.c.

modbus_char_recvd()

void modbus_char_recvd

(

void

)

This function will be called every time a character has been received on the Modbus serial port. It is called from the interrupt hander.

Parameters

c	: the received char // removed !

See also

interrupts.c.

Definition at line 85 of file modbus.c.

modbus_init()

void modbus_init

(

uint8_t

address

)

Initializes this Modbus library.

Initialize pins, timer, serial port and variables. Interrupts MUST be initialized for the timer and the serial port.

Parameters

address

: the Modbus address of this device

See also

modbus_char_recvd

modbus_timer

interrupts.c

Definition at line 108 of file modbus.c.

modbus_send()

void modbus_send

(

uint8_t

length

)

Send the Modbus frame on tx_buf with CRC added

Parameters

length

: length of the frame without the CRC

Definition at line 92 of file modbus.c.

modbus_timer()

void modbus_timer

(

void

)

Modbus timer finished. This function is called by the interrupt handler when a MODBUS frame is finished. It must analyse the received packet and reply if required.

See also

interrupts.c

Definition at line 33 of file modbus.c.

Variable Documentation

holding_registers

uint16_t holding_registers[2]

Definition at line 14 of file modbus.c.

input_registers

uint16_t input_registers[2]

Definition at line 13 of file modbus.c.

modbusAddress

uint8_t modbusAddress

Definition at line 12 of file modbus.c.

recPtr

uint8_t recPtr = 0

Definition at line 31 of file modbus.c.

rx_buf

uint8_t rx_buf[256]

Buffers for serial receive and send operations which are more than one byte long

Definition at line 27 of file modbus.c.

tx_buf

uint8_t tx_buf[256]

Definition at line 28 of file modbus.c.