/**
* @file ModbusRtu.h
* @version 1.21
* @date 2016.02.21
* @author Samuel Marco i Armengol
* @contact sammarcoarmengol@gmail.com
* @contribution Helium6072
* @contribution gabrielsan
*
* @description
* Arduino library for communicating with Modbus devices
* over RS232/USB/485 via RTU protocol.
*
* Further information:
* http://modbus.org/
* http://modbus.org/docs/Modbus_over_serial_line_V1_02.pdf
*
* @license
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; version
* 2.1 of the License.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
* @defgroup setup Modbus Object Instantiation/Initialization
* @defgroup loop Modbus Object Management
* @defgroup buffer Modbus Buffer Management
* @defgroup discrete Modbus Function Codes for Discrete Coils/Inputs
* @defgroup register Modbus Function Codes for Holding/Input Registers
*
*/
#include <ModbusRtu.h>
/* _____PUBLIC FUNCTIONS_____________________________________________________ */
/**
* @brief
* Constructor for a Master/Slave.
*
* For hardware serial through USB/RS232C/RS485 set port to Serial, Serial1,
* Serial2, or Serial3. (Numbered hardware serial ports are only available on
* some boards.)
*
* For software serial through RS232C/RS485 set port to a SoftwareSerial object
* that you have already constructed.
*
* ModbusRtu needs a pin for flow control only for RS485 mode. Pins 0 and 1
* cannot be used.
*
* First call begin() on your serial port, and then start up ModbusRtu by
* calling start(). You can choose the line speed and other port parameters
* by passing the appropriate values to the port's begin() function.
*
* @param u8id node address 0=master, 1..247=slave
* @param port serial port used
* @param u8txenpin pin for txen RS-485 (=0 means USB/RS232C mode)
* @ingroup setup
*/
Modbus::Modbus(uint8_t u8id, Stream& port, uint8_t u8txenpin)
{
this->port = &port;
this->u8id = u8id;
this->u8txenpin = u8txenpin;
this->u16timeOut = 1000;
this->u32overTime = 0;
}
/**
* @brief
* DEPRECATED constructor for a Master/Slave.
*
* THIS CONSTRUCTOR IS ONLY PROVIDED FOR BACKWARDS COMPATIBILITY.
* USE Modbus(uint8_t, T_Stream&, uint8_t) INSTEAD.
*
* @param u8id node address 0=master, 1..247=slave
* @param u8serno serial port used 0..3 (ignored for software serial)
* @param u8txenpin pin for txen RS-485 (=0 means USB/RS232C mode)
* @ingroup setup
* @overload Modbus::Modbus(uint8_t u8id, T_Stream& port, uint8_t u8txenpin)
*/
Modbus::Modbus(uint8_t u8id, uint8_t u8serno, uint8_t u8txenpin)
{
this->u8id = u8id;
this->u8txenpin = u8txenpin;
this->u16timeOut = 1000;
this->u32overTime = 0;
switch( u8serno )
{
#if defined(UBRR1H)
case 1:
port = &Serial1;
break;
#endif
#if defined(UBRR2H)
case 2:
port = &Serial2;
break;
#endif
#if defined(UBRR3H)
case 3:
port = &Serial3;
break;
#endif
case 0:
default:
port = &Serial;
break;
}
}
/**
* @brief
* Start-up class object.
*
* Call this AFTER calling begin() on the serial port, typically within setup().
*
* (If you call this function, then you should NOT call any of
* ModbusRtu's own begin() functions.)
*
* @ingroup setup
*/
void Modbus::start()
{
if (u8txenpin > 1) // pin 0 & pin 1 are reserved for RX/TX
{
// return RS485 transceiver to transmit mode
pinMode(u8txenpin, OUTPUT);
digitalWrite(u8txenpin, LOW);
}
while(port->read() >= 0);
u8lastRec = u8BufferSize = 0;
u16InCnt = u16OutCnt = u16errCnt = 0;
}
/**
* @brief
* DEPRECATED Install a serial port, begin() it, and start ModbusRtu.
*
* ONLY PROVIDED FOR BACKWARDS COMPATIBILITY.
* USE Serial.begin(<baud rate>); FOLLOWED BY Modbus.start() INSTEAD.
*
* @param install_port pointer to SoftwareSerial or HardwareSerial class object
* @param u32speed baud rate, in standard increments (300..115200)
* @ingroup setup
*/
template<typename T_Stream>
void Modbus::begin(T_Stream* install_port, long u32speed)
{
port = install_port;
install_port->begin(u32speed);
start();
}
/**
* @brief
* DEPRECATED. Install a serial port, begin() it, and start ModbusRtu.
*
* ONLY PROVIDED FOR BACKWARDS COMPATIBILITY.
* USE Serial.begin(<baud rate>); FOLLOWED BY Modbus.start() INSTEAD.
*
* @param install_port pointer to SoftwareSerial or HardwareSerial class object
* @param u32speed baud rate, in standard increments (300..115200)
* @param u8txenpin pin for txen RS-485 (=0 means USB/RS232C mode)
* @ingroup setup
*/
template<typename T_Stream>
void Modbus::begin(T_Stream* install_port, long u32speed, uint8_t u8txenpin)
{
this->u8txenpin = u8txenpin;
this->port = install_port;
install_port->begin(u32speed);
start();
}
/**
* @brief
* DEPRECATED. begin() hardware serial port and start ModbusRtu.
*
* ONLY PROVIDED FOR BACKWARDS COMPATIBILITY.
* USE Serial.begin(<baud rate>); FOLLOWED BY Modbus.start() INSTEAD.
*
* @see http://arduino.cc/en/Serial/Begin#.Uy4CJ6aKlHY
* @param speed baud rate, in standard increments (300..115200). Default=19200
* @ingroup setup
*/
void Modbus::begin(long u32speed)
{
// !!Can ONLY do this if port ACTUALLY IS a HardwareSerial object!!
static_cast<HardwareSerial*>(port)->begin(u32speed);
start();
}
/**
* @brief
* Method to write a new slave ID address
*
* @param u8id new slave address between 1 and 247
* @ingroup setup
*/
void Modbus::setID( uint8_t u8id)
{
if (( u8id != 0) && (u8id <= 247))
{
this->u8id = u8id;
}
}
/**
* @brief
* Method to write the overtime count for txend pin.
* It waits until count reaches 0 after the transfer is done.
* With this, you can extend the time between txempty and
* the falling edge if needed.
*
* @param uint32_t overtime count for txend pin
* @ingroup setup
*/
void Modbus::setTxendPinOverTime( uint32_t u32overTime )
{
this->u32overTime = u32overTime;
}
/**
* @brief
* Method to read current slave ID address
*
* @return u8id current slave address between 1 and 247
* @ingroup setup
*/
uint8_t Modbus::getID()
{
return this->u8id;
}
/**
* @brief
* Initialize time-out parameter
*
* Call once class has been instantiated, typically within setup().
* The time-out timer is reset each time that there is a successful communication
* between Master and Slave. It works for both.
*
* @param time-out value (ms)
* @ingroup setup
*/
void Modbus::setTimeOut( uint16_t u16timeOut)
{
this->u16timeOut = u16timeOut;
}
/**
* @brief
* Return communication Watchdog state.
* It could be usefull to reset outputs if the watchdog is fired.
*
* @return TRUE if millis() > u32timeOut
* @ingroup loop
*/
boolean Modbus::getTimeOutState()
{
return ((unsigned long)(millis() -u32timeOut) > (unsigned long)u16timeOut);
}
/**
* @brief
* Get input messages counter value
* This can be useful to diagnose communication
*
* @return input messages counter
* @ingroup buffer
*/
uint16_t Modbus::getInCnt()
{
return u16InCnt;
}
/**
* @brief
* Get transmitted messages counter value
* This can be useful to diagnose communication
*
* @return transmitted messages counter
* @ingroup buffer
*/
uint16_t Modbus::getOutCnt()
{
return u16OutCnt;
}
/**
* @brief
* Get errors counter value
* This can be useful to diagnose communication
*
* @return errors counter
* @ingroup buffer
*/
uint16_t Modbus::getErrCnt()
{
return u16errCnt;
}
/**
* Get modbus master state
*
* @return = 0 IDLE, = 1 WAITING FOR ANSWER
* @ingroup buffer
*/
uint8_t Modbus::getState()
{
return u8state;
}
/**
* Get the last error in the protocol processor
*
* @returnreturn NO_REPLY = 255 Time-out
* @return EXC_FUNC_CODE = 1 Function code not available
* @return EXC_ADDR_RANGE = 2 Address beyond available space for Modbus registers
* @return EXC_REGS_QUANT = 3 Coils or registers number beyond the available space
* @ingroup buffer
*/
uint8_t Modbus::getLastError()
{
return u8lastError;
}
/**
* @brief
* *** Only Modbus Master ***
* Generate a query to an slave with a modbus_t telegram structure
* The Master must be in COM_IDLE mode. After it, its state would be COM_WAITING.
* This method has to be called only in loop() section.
*
* @see modbus_t
* @param modbus_t modbus telegram structure (id, fct, ...)
* @ingroup loop
* @todo finish function 15
*/
int8_t Modbus::query( modbus_t telegram )
{
uint8_t u8regsno, u8bytesno;
if (u8id!=0) return -2;
if (u8state != COM_IDLE) return -1;
if ((telegram.u8id==0) || (telegram.u8id>247)) return -3;
au16regs = telegram.au16reg;
// telegram header
au8Buffer[ ID ] = telegram.u8id;
au8Buffer[ FUNC ] = telegram.u8fct;
au8Buffer[ ADD_HI ] = highByte(telegram.u16RegAdd );
au8Buffer[ ADD_LO ] = lowByte( telegram.u16RegAdd );
switch( telegram.u8fct )
{
case MB_FC_READ_COILS:
case MB_FC_READ_DISCRETE_INPUT:
case MB_FC_READ_REGISTERS:
case MB_FC_READ_INPUT_REGISTER:
au8Buffer[ NB_HI ] = highByte(telegram.u16CoilsNo );
au8Buffer[ NB_LO ] = lowByte( telegram.u16CoilsNo );
u8BufferSize = 6;
break;
case MB_FC_WRITE_COIL:
au8Buffer[ NB_HI ] = ((au16regs[0] > 0) ? 0xff : 0);
au8Buffer[ NB_LO ] = 0;
u8BufferSize = 6;
break;
case MB_FC_WRITE_REGISTER:
au8Buffer[ NB_HI ] = highByte(au16regs[0]);
au8Buffer[ NB_LO ] = lowByte(au16regs[0]);
u8BufferSize = 6;
break;
case MB_FC_WRITE_MULTIPLE_COILS: // TODO: implement "sending coils"
u8regsno = telegram.u16CoilsNo / 16;
u8bytesno = u8regsno * 2;
if ((telegram.u16CoilsNo % 16) != 0)
{
u8bytesno++;
u8regsno++;
}
au8Buffer[ NB_HI ] = highByte(telegram.u16CoilsNo );
au8Buffer[ NB_LO ] = lowByte( telegram.u16CoilsNo );
au8Buffer[ BYTE_CNT ] = u8bytesno;
u8BufferSize = 7;
for (uint16_t i = 0; i < u8bytesno; i++)
{
if(i%2)
{
au8Buffer[ u8BufferSize ] = lowByte( au16regs[ i/2 ] );
}
else
{
au8Buffer[ u8BufferSize ] = highByte( au16regs[ i/2] );
}
u8BufferSize++;
}
break;
case MB_FC_WRITE_MULTIPLE_REGISTERS:
au8Buffer[ NB_HI ] = highByte(telegram.u16CoilsNo );
au8Buffer[ NB_LO ] = lowByte( telegram.u16CoilsNo );
au8Buffer[ BYTE_CNT ] = (uint8_t) ( telegram.u16CoilsNo * 2 );
u8BufferSize = 7;
for (uint16_t i=0; i< telegram.u16CoilsNo; i++)
{
au8Buffer[ u8BufferSize ] = highByte( au16regs[ i ] );
u8BufferSize++;
au8Buffer[ u8BufferSize ] = lowByte( au16regs[ i ] );
u8BufferSize++;
}
break;
}
sendTxBuffer();
u8state = COM_WAITING;
u8lastError = 0;
return 0;
}
/**
* @brief *** Only for Modbus Master ***
* This method checks if there is any incoming answer if pending.
* If there is no answer, it would change Master state to COM_IDLE.
* This method must be called only at loop section.
* Avoid any delay() function.
*
* Any incoming data would be redirected to au16regs pointer,
* as defined in its modbus_t query telegram.
*
* @params nothing
* @return errors counter
* @ingroup loop
*/
int8_t Modbus::poll()
{
// check if there is any incoming frame
uint8_t u8current;
u8current = port->available();
if ((unsigned long)(millis() -u32timeOut) > (unsigned long)u16timeOut)
{
u8state = COM_IDLE;
u8lastError = NO_REPLY;
u16errCnt++;
return 0;
}
if (u8current == 0) return 0;
// check T35 after frame end or still no frame end
if (u8current != u8lastRec)
{
u8lastRec = u8current;
u32time = millis();
return 0;
}
if ((unsigned long)(millis() -u32time) < (unsigned long)T35) return 0;
// transfer Serial buffer frame to auBuffer
u8lastRec = 0;
int8_t i8state = getRxBuffer();
if (i8state < 6) //7 was incorrect for functions 1 and 2 the smallest frame could be 6 bytes long
{
u8state = COM_IDLE;
u16errCnt++;
return i8state;
}
// validate message: id, CRC, FCT, exception
uint8_t u8exception = validateAnswer();
if (u8exception != 0)
{
u8state = COM_IDLE;
return u8exception;
}
// process answer
switch( au8Buffer[ FUNC ] )
{
case MB_FC_READ_COILS:
case MB_FC_READ_DISCRETE_INPUT:
// call get_FC1 to transfer the incoming message to au16regs buffer
get_FC1( );
break;
case MB_FC_READ_INPUT_REGISTER:
case MB_FC_READ_REGISTERS :
// call get_FC3 to transfer the incoming message to au16regs buffer
get_FC3( );
break;
case MB_FC_WRITE_COIL:
case MB_FC_WRITE_REGISTER :
case MB_FC_WRITE_MULTIPLE_COILS:
case MB_FC_WRITE_MULTIPLE_REGISTERS :
// nothing to do
break;
default:
break;
}
u8state = COM_IDLE;
return u8BufferSize;
}
/**
* @brief
* *** Only for Modbus Slave ***
* This method checks if there is any incoming query
* Afterwards, it would shoot a validation routine plus a register query
* Avoid any delay() function !!!!
* After a successful frame between the Master and the Slave, the time-out timer is reset.
*
* @param *regs register table for communication exchange
* @param u8size size of the register table
* @return 0 if no query, 1..4 if communication error, >4 if correct query processed
* @ingroup loop
*/
int8_t Modbus::poll( uint16_t *regs, uint8_t u8size )
{
au16regs = regs;
u8regsize = u8size;
uint8_t u8current;
// check if there is any incoming frame
u8current = port->available();
if (u8current == 0) return 0;
// check T35 after frame end or still no frame end
if (u8current != u8lastRec)
{
u8lastRec = u8current;
u32time = millis();
return 0;
}
if ((unsigned long)(millis() -u32time) < (unsigned long)T35) return 0;
u8lastRec = 0;
int8_t i8state = getRxBuffer();
u8lastError = i8state;
if (i8state < 7) return i8state;
// check slave id
if (au8Buffer[ ID ] != u8id) return 0;
// validate message: CRC, FCT, address and size
uint8_t u8exception = validateRequest();
if (u8exception > 0)
{
if (u8exception != NO_REPLY)
{
buildException( u8exception );
sendTxBuffer();
}
u8lastError = u8exception;
return u8exception;
}
u32timeOut = millis();
u8lastError = 0;
// process message
switch( au8Buffer[ FUNC ] )
{
case MB_FC_READ_COILS:
case MB_FC_READ_DISCRETE_INPUT:
return process_FC1( regs, u8size );
break;
case MB_FC_READ_INPUT_REGISTER:
case MB_FC_READ_REGISTERS :
return process_FC3( regs, u8size );
break;
case MB_FC_WRITE_COIL:
return process_FC5( regs, u8size );
break;
case MB_FC_WRITE_REGISTER :
return process_FC6( regs, u8size );
break;
case MB_FC_WRITE_MULTIPLE_COILS:
return process_FC15( regs, u8size );
break;
case MB_FC_WRITE_MULTIPLE_REGISTERS :
return process_FC16( regs, u8size );
break;
default:
break;
}
return i8state;
}
/* _____PRIVATE FUNCTIONS_____________________________________________________ */
/**
* @brief
* This method moves Serial buffer data to the Modbus au8Buffer.
*
* @return buffer size if OK, ERR_BUFF_OVERFLOW if u8BufferSize >= MAX_BUFFER
* @ingroup buffer
*/
int8_t Modbus::getRxBuffer()
{
boolean bBuffOverflow = false;
if (u8txenpin > 1) digitalWrite( u8txenpin, LOW );
u8BufferSize = 0;
while ( port->available() )
{
au8Buffer[ u8BufferSize ] = port->read();
u8BufferSize ++;
if (u8BufferSize >= MAX_BUFFER) bBuffOverflow = true;
}
u16InCnt++;
if (bBuffOverflow)
{
u16errCnt++;
return ERR_BUFF_OVERFLOW;
}
return u8BufferSize;
}
/**
* @brief
* This method transmits au8Buffer to Serial line.
* Only if u8txenpin != 0, there is a flow handling in order to keep
* the RS485 transceiver in output state as long as the message is being sent.
* This is done with UCSRxA register.
* The CRC is appended to the buffer before starting to send it.
*
* @param nothing
* @return nothing
* @ingroup buffer
*/
void Modbus::sendTxBuffer()
{
// append CRC to message
uint16_t u16crc = calcCRC( u8BufferSize );
au8Buffer[ u8BufferSize ] = u16crc >> 8;
u8BufferSize++;
au8Buffer[ u8BufferSize ] = u16crc & 0x00ff;
u8BufferSize++;
if (u8txenpin > 1)
{
// set RS485 transceiver to transmit mode
digitalWrite( u8txenpin, HIGH );
}
// transfer buffer to serial line
port->write( au8Buffer, u8BufferSize );
if (u8txenpin > 1)
{
// must wait transmission end before changing pin state
// soft serial does not need it since it is blocking
// ...but the implementation in SoftwareSerial does nothing
// anyway, so no harm in calling it.
port->flush();
// return RS485 transceiver to receive mode
volatile uint32_t u32overTimeCountDown = u32overTime;
while ( u32overTimeCountDown-- > 0);
digitalWrite( u8txenpin, LOW );
}
while(port->read() >= 0);
u8BufferSize = 0;
// set time-out for master
u32timeOut = millis();
// increase message counter
u16OutCnt++;
}
/**
* @brief
* This method calculates CRC
*
* @return uint16_t calculated CRC value for the message
* @ingroup buffer
*/
uint16_t Modbus::calcCRC(uint8_t u8length)
{
unsigned int temp, temp2, flag;
temp = 0xFFFF;
for (unsigned char i = 0; i < u8length; i++)
{
temp = temp ^ au8Buffer[i];
for (unsigned char j = 1; j <= 8; j++)
{
flag = temp & 0x0001;
temp >>=1;
if (flag)
temp ^= 0xA001;
}
}
// Reverse byte order.
temp2 = temp >> 8;
temp = (temp << 8) | temp2;
temp &= 0xFFFF;
// the returned value is already swapped
// crcLo byte is first & crcHi byte is last
return temp;
}
/**
* @brief
* This method validates slave incoming messages
*
* @return 0 if OK, EXCEPTION if anything fails
* @ingroup buffer
*/
uint8_t Modbus::validateRequest()
{
// check message crc vs calculated crc
uint16_t u16MsgCRC =
((au8Buffer[u8BufferSize - 2] << 8)
| au8Buffer[u8BufferSize - 1]); // combine the crc Low & High bytes
if ( calcCRC( u8BufferSize-2 ) != u16MsgCRC )
{
u16errCnt ++;
return NO_REPLY;
}
// check fct code
boolean isSupported = false;
for (uint8_t i = 0; i< sizeof( fctsupported ); i++)
{
if (fctsupported[i] == au8Buffer[FUNC])
{
isSupported = 1;
break;
}
}
if (!isSupported)
{
u16errCnt ++;
return EXC_FUNC_CODE;
}
// check start address & nb range
uint16_t u16regs = 0;
uint8_t u8regs;
switch ( au8Buffer[ FUNC ] )
{
case MB_FC_READ_COILS:
case MB_FC_READ_DISCRETE_INPUT:
case MB_FC_WRITE_MULTIPLE_COILS:
u16regs = word( au8Buffer[ ADD_HI ], au8Buffer[ ADD_LO ]) / 16;
u16regs += word( au8Buffer[ NB_HI ], au8Buffer[ NB_LO ]) /16;
u8regs = (uint8_t) u16regs;
if (u8regs > u8regsize) return EXC_ADDR_RANGE;
break;
case MB_FC_WRITE_COIL:
u16regs = word( au8Buffer[ ADD_HI ], au8Buffer[ ADD_LO ]) / 16;
u8regs = (uint8_t) u16regs;
if (u8regs > u8regsize) return EXC_ADDR_RANGE;
break;
case MB_FC_WRITE_REGISTER :
u16regs = word( au8Buffer[ ADD_HI ], au8Buffer[ ADD_LO ]);
u8regs = (uint8_t) u16regs;
if (u8regs > u8regsize) return EXC_ADDR_RANGE;
break;
case MB_FC_READ_REGISTERS :
case MB_FC_READ_INPUT_REGISTER :
case MB_FC_WRITE_MULTIPLE_REGISTERS :
u16regs = word( au8Buffer[ ADD_HI ], au8Buffer[ ADD_LO ]);
u16regs += word( au8Buffer[ NB_HI ], au8Buffer[ NB_LO ]);
u8regs = (uint8_t) u16regs;
if (u8regs > u8regsize) return EXC_ADDR_RANGE;
break;
}
return 0; // OK, no exception code thrown
}
/**
* @brief
* This method validates master incoming messages
*
* @return 0 if OK, EXCEPTION if anything fails
* @ingroup buffer
*/
uint8_t Modbus::validateAnswer()
{
// check message crc vs calculated crc
uint16_t u16MsgCRC =
((au8Buffer[u8BufferSize - 2] << 8)
| au8Buffer[u8BufferSize - 1]); // combine the crc Low & High bytes
if ( calcCRC( u8BufferSize-2 ) != u16MsgCRC )
{
u16errCnt ++;
return NO_REPLY;
}
// check exception
if ((au8Buffer[ FUNC ] & 0x80) != 0)
{
u16errCnt ++;
return ERR_EXCEPTION;
}
// check fct code
boolean isSupported = false;
for (uint8_t i = 0; i< sizeof( fctsupported ); i++)
{
if (fctsupported[i] == au8Buffer[FUNC])
{
isSupported = 1;
break;
}
}
if (!isSupported)
{
u16errCnt ++;
return EXC_FUNC_CODE;
}
return 0; // OK, no exception code thrown
}
/**
* @brief
* This method builds an exception message
*
* @ingroup buffer
*/
void Modbus::buildException( uint8_t u8exception )
{
uint8_t u8func = au8Buffer[ FUNC ]; // get the original FUNC code
au8Buffer[ ID ] = u8id;
au8Buffer[ FUNC ] = u8func + 0x80;
au8Buffer[ 2 ] = u8exception;
u8BufferSize = EXCEPTION_SIZE;
}
/**
* This method processes functions 1 & 2 (for master)
* This method puts the slave answer into master data buffer
*
* @ingroup register
* TODO: finish its implementation
*/
void Modbus::get_FC1()
{
uint8_t u8byte, i;
u8byte = 3;
for (i=0; i< au8Buffer[2]; i++) {
if(i%2)
{
au16regs[i/2]= word(au8Buffer[i+u8byte], lowByte(au16regs[i/2]));
}
else
{
au16regs[i/2]= word(highByte(au16regs[i/2]), au8Buffer[i+u8byte]);
}
}
}
/**
* This method processes functions 3 & 4 (for master)
* This method puts the slave answer into master data buffer
*
* @ingroup register
*/
void Modbus::get_FC3()
{
uint8_t u8byte, i;
u8byte = 3;
for (i=0; i< au8Buffer[ 2 ] /2; i++)
{
au16regs[ i ] = word(
au8Buffer[ u8byte ],
au8Buffer[ u8byte +1 ]);
u8byte += 2;
}
}
/**
* @brief
* This method processes functions 1 & 2
* This method reads a bit array and transfers it to the master
*
* @return u8BufferSize Response to master length
* @ingroup discrete
*/
int8_t Modbus::process_FC1( uint16_t *regs, uint8_t /*u8size*/ )
{
uint8_t u8currentRegister, u8currentBit, u8bytesno, u8bitsno;
uint8_t u8CopyBufferSize;
uint16_t u16currentCoil, u16coil;
// get the first and last coil from the message
uint16_t u16StartCoil = word( au8Buffer[ ADD_HI ], au8Buffer[ ADD_LO ] );
uint16_t u16Coilno = word( au8Buffer[ NB_HI ], au8Buffer[ NB_LO ] );
// put the number of bytes in the outcoming message
u8bytesno = (uint8_t) (u16Coilno / 8);
if (u16Coilno % 8 != 0) u8bytesno ++;
au8Buffer[ ADD_HI ] = u8bytesno;
u8BufferSize = ADD_LO;
au8Buffer[ u8BufferSize + u8bytesno - 1 ] = 0;
// read each coil from the register map and put its value inside the outcoming message
u8bitsno = 0;
for (u16currentCoil = 0; u16currentCoil < u16Coilno; u16currentCoil++)
{
u16coil = u16StartCoil + u16currentCoil;
u8currentRegister = (uint8_t) (u16coil / 16);
u8currentBit = (uint8_t) (u16coil % 16);
bitWrite(
au8Buffer[ u8BufferSize ],
u8bitsno,
bitRead( regs[ u8currentRegister ], u8currentBit ) );
u8bitsno ++;
if (u8bitsno > 7)
{
u8bitsno = 0;
u8BufferSize++;
}
}
// send outcoming message
if (u16Coilno % 8 != 0) u8BufferSize ++;
u8CopyBufferSize = u8BufferSize +2;
sendTxBuffer();
return u8CopyBufferSize;
}
/**
* @brief
* This method processes functions 3 & 4
* This method reads a word array and transfers it to the master
*
* @return u8BufferSize Response to master length
* @ingroup register
*/
int8_t Modbus::process_FC3( uint16_t *regs, uint8_t /*u8size*/ )
{
uint8_t u8StartAdd = word( au8Buffer[ ADD_HI ], au8Buffer[ ADD_LO ] );
uint8_t u8regsno = word( au8Buffer[ NB_HI ], au8Buffer[ NB_LO ] );
uint8_t u8CopyBufferSize;
uint8_t i;
au8Buffer[ 2 ] = u8regsno * 2;
u8BufferSize = 3;
for (i = u8StartAdd; i < u8StartAdd + u8regsno; i++)
{
au8Buffer[ u8BufferSize ] = highByte(regs[i]);
u8BufferSize++;
au8Buffer[ u8BufferSize ] = lowByte(regs[i]);
u8BufferSize++;
}
u8CopyBufferSize = u8BufferSize +2;
sendTxBuffer();
return u8CopyBufferSize;
}
/**
* @brief
* This method processes function 5
* This method writes a value assigned by the master to a single bit
*
* @return u8BufferSize Response to master length
* @ingroup discrete
*/
int8_t Modbus::process_FC5( uint16_t *regs, uint8_t /*u8size*/ )
{
uint8_t u8currentRegister, u8currentBit;
uint8_t u8CopyBufferSize;
uint16_t u16coil = word( au8Buffer[ ADD_HI ], au8Buffer[ ADD_LO ] );
// point to the register and its bit
u8currentRegister = (uint8_t) (u16coil / 16);
u8currentBit = (uint8_t) (u16coil % 16);
// write to coil
bitWrite(
regs[ u8currentRegister ],
u8currentBit,
au8Buffer[ NB_HI ] == 0xff );
// send answer to master
u8BufferSize = 6;
u8CopyBufferSize = u8BufferSize +2;
sendTxBuffer();
return u8CopyBufferSize;
}
/**
* @brief
* This method processes function 6
* This method writes a value assigned by the master to a single word
*
* @return u8BufferSize Response to master length
* @ingroup register
*/
int8_t Modbus::process_FC6( uint16_t *regs, uint8_t /*u8size*/ )
{
uint8_t u8add = word( au8Buffer[ ADD_HI ], au8Buffer[ ADD_LO ] );
uint8_t u8CopyBufferSize;
uint16_t u16val = word( au8Buffer[ NB_HI ], au8Buffer[ NB_LO ] );
regs[ u8add ] = u16val;
// keep the same header
u8BufferSize = RESPONSE_SIZE;
u8CopyBufferSize = u8BufferSize +2;
sendTxBuffer();
return u8CopyBufferSize;
}
/**
* @brief
* This method processes function 15
* This method writes a bit array assigned by the master
*
* @return u8BufferSize Response to master length
* @ingroup discrete
*/
int8_t Modbus::process_FC15( uint16_t *regs, uint8_t /*u8size*/ )
{
uint8_t u8currentRegister, u8currentBit, u8frameByte, u8bitsno;
uint8_t u8CopyBufferSize;
uint16_t u16currentCoil, u16coil;
boolean bTemp;
// get the first and last coil from the message
uint16_t u16StartCoil = word( au8Buffer[ ADD_HI ], au8Buffer[ ADD_LO ] );
uint16_t u16Coilno = word( au8Buffer[ NB_HI ], au8Buffer[ NB_LO ] );
// read each coil from the register map and put its value inside the outcoming message
u8bitsno = 0;
u8frameByte = 7;
for (u16currentCoil = 0; u16currentCoil < u16Coilno; u16currentCoil++)
{
u16coil = u16StartCoil + u16currentCoil;
u8currentRegister = (uint8_t) (u16coil / 16);
u8currentBit = (uint8_t) (u16coil % 16);
bTemp = bitRead(
au8Buffer[ u8frameByte ],
u8bitsno );
bitWrite(
regs[ u8currentRegister ],
u8currentBit,
bTemp );
u8bitsno ++;
if (u8bitsno > 7)
{
u8bitsno = 0;
u8frameByte++;
}
}
// send outcoming message
// it's just a copy of the incomping frame until 6th byte
u8BufferSize = 6;
u8CopyBufferSize = u8BufferSize +2;
sendTxBuffer();
return u8CopyBufferSize;
}
/**
* @brief
* This method processes function 16
* This method writes a word array assigned by the master
*
* @return u8BufferSize Response to master length
* @ingroup register
*/
int8_t Modbus::process_FC16( uint16_t *regs, uint8_t /*u8size*/ )
{
uint8_t u8StartAdd = au8Buffer[ ADD_HI ] << 8 | au8Buffer[ ADD_LO ];
uint8_t u8regsno = au8Buffer[ NB_HI ] << 8 | au8Buffer[ NB_LO ];
uint8_t u8CopyBufferSize;
uint8_t i;
uint16_t temp;
// build header
au8Buffer[ NB_HI ] = 0;
au8Buffer[ NB_LO ] = u8regsno;
u8BufferSize = RESPONSE_SIZE;
// write registers
for (i = 0; i < u8regsno; i++)
{
temp = word(
au8Buffer[ (BYTE_CNT + 1) + i * 2 ],
au8Buffer[ (BYTE_CNT + 2) + i * 2 ]);
regs[ u8StartAdd + i ] = temp;
}
u8CopyBufferSize = u8BufferSize +2;
sendTxBuffer();
return u8CopyBufferSize;
}