/***************************************************************************\
	Dynamic C MODBus ASCII/RTU Master
		Copyright (c) 2002 Z-World, Inc.
		Portions Copyright (c) 1999, CFControls, Inc.
\***************************************************************************/

/*
** MODBus query and response communications have the following default
** (standard or arbitrary) time out limits.
**
** MODBus ASCII query end to response begin is 1000 mS (standard).
**
** MODBus ASCII inter-character is 1000 mS (standard).
**
** MODBus RTU query end to response begin is 100 mS (arbitrary).
**
** MODBus RTU inter-character and transmission end is a 3.5 character
** times gap (standard), which depends on the serial transmission
** format and rate. The default assumes 11 (EG: 1 start, 8 data, 2
** stop) bits per character, and uses the bps rate specified when RTU
** communication is initialized. An extra 1 mS is added to the gap to
** ensure that the calculation's result is always rounded up, not down.
**
** The application can override these MODBus ASCII and RTU defaults by
** defining MM_BRTO (Begin Response Time Out) and/or MM_ERTO (End
** Response Time Out) in milliseconds (long integer).
**
** EG: #define MM_BRTO 2000L  // allow long (2 S) query/response delay
**     #define MM_ERTO 1L     // set short (1 mS) inter-character delay
*/

/*** BeginHeader */
#ifndef __MM_RAB_LIB
#define __MM_RAB_LIB

// User supplied function prototypes (see MMZ_RAB.LIB for examples)
int mmRecv();
int mmSend(unsigned char *pcMess,unsigned wLen);

// Extended MODBus Master Exceptions (NB: always zero or negative)
#define	MM_NOBROAD	(-9)	// Broadcast Not Supported
#define	MM_TIMEOUT	(-8)	// Response Timeout
#define	MM_GARBAGE	(-7)	// Garbage In Response
#define	MM_TOOLONG	(-6)	// Response Exceeds Buffer Length
#define	MM_BADXRC	(-5)	// Bad CRC/LRC
#define	MM_BADID		(-4)	// Unexpected Slave ID in Response
#define	MM_BADCODE	(-3)	// Unexpected Response Code
#define	MM_RESCODE	(-2)	// Reserved Exception Code (zero)
#define	MM_OK			(-1)	// Success
#define	MM_BUSY		0		// Master Still Processing

//	Supported MODBus Slave Exceptions (NB: always positive)
#define	MS_BADFUNC	0x01	// Illegal Function
#define	MS_BADADDR	0x02	// Illegal Data Address
#define	MS_BADDATA	0x03	// Illegal Data Value
// NB: The following two slave exception names are synonymous.
#define	MS_BADRESP	0x04	// Illegal Response Length (unrecoverable error)
#define	MS_DEVFAIL	0x04	// Slave Device Failure (unrecoverable error)
#define	MS_ACK		0x05	// Acknowledge (long duration program)
#define	MS_DEVBUSY	0x06	// Slave Device Busy (long duration program)
#define	MS_NACK		0x07	// Negative Acknowledge (reject program)
#define	MS_MEMPERR	0x08	// Memory Parity Error (read extended memory)
#define	MS_NOGPATH	0x0A	// Gateway Path Unavailable (Modbus Plus)
#define	MS_NOGRESP	0x0B	// Gateway Target Device Failed to Respond
/*** EndHeader */

/* START FUNCTION DESCRIPTION *****************************************
mmRecv                        <Required by MM_RAB.LIB>

NOTE: MM.LIB functions are generally not reentrant.

SYNTAX: int mmRecv()

DESCRIPTION: Receive one byte from the Modbus Master communication
port. This port-specific function is called by functions in MM.LIB, see
MMZ.LIB for examples.

RETURN VALUE: The current byte (0 to 255), or -1 if none available.
END DESCRIPTION ******************************************************/

/* START FUNCTION DESCRIPTION *****************************************
mmSend                        <Required by MM_RAB.LIB>

NOTE: MM_RAB.LIB functions are generally not reentrant.

SYNTAX: int mmSend(unsigned char *pcMess, unsigned wLen);

DESCRIPTION: Transmit data out the Modbus Master communication port.
This port-specific function is called by functions in MM_RAB.LIB, see
MMZ.LIB for examples.

PARAMETER1: data buffer pointer
PARAMETER2: length of data in buffer

RETURN VALUE: 0 while busy transmitting data, 1 if successfully done.
END DESCRIPTION ******************************************************/

/***************************************************************************\
	MODBus Packet Utilities & ASCII+RTU Globals
\***************************************************************************/

/*** BeginHeader mmRepWord, mmCmdByte, mmCmdWord, mmCmdNew,
		acMMCmd, acMMRep, pcMMCmd, pcMMRep */

unsigned mmRepWord(unsigned);
int mmCmdByte(unsigned char);
int mmCmdWord(unsigned);
void mmCmdNew(unsigned,unsigned);

// global variables for Modbus ASCII+RTU
extern unsigned char acMMCmd[256];
extern unsigned char acMMRep[256];
extern shared unsigned char *pcMMCmd;
extern shared unsigned char *pcMMRep;
/*** EndHeader */

unsigned char acMMCmd[256];		//	Command Buffer
unsigned char acMMRep[256];		//	Reply Buffer
shared unsigned char *pcMMCmd;	//	Command Pointer
shared unsigned char *pcMMRep;	//	Reply Pointer

/*=========================================================================*\
	Extract Word(MSB First) from Reply Body
\*=========================================================================*/

nodebug
unsigned mmRepWord(unsigned wOff)
{
	return((unsigned) acMMRep[wOff] << 8) + acMMRep[wOff + 1];
}

/*=========================================================================*\
	Add Byte to Command Body
\*=========================================================================*/

nodebug
int mmCmdByte(unsigned char cByte)
{
	if(&acMMCmd[sizeof(acMMCmd) - 1] <= pcMMCmd)
		return 0;
	*pcMMCmd++ = cByte;
	return 1;
}

/*=========================================================================*\
	Add Word to Command (MSB First)
\*=========================================================================*/

nodebug
int mmCmdWord(unsigned wWord)
{
	return(mmCmdByte((unsigned char) (wWord >> 8)) &&
	 mmCmdByte((unsigned char) (wWord & 0xFF)));
}

/*=========================================================================*\
	Start New Command
\*=========================================================================*/

nodebug
void mmCmdNew(unsigned wAddr, unsigned wCmd)
{
	pcMMCmd = acMMCmd;									// Reset Reply Pointer
	mmCmdByte((unsigned char) (wAddr & 0xFF));	// Slave Address
	mmCmdByte((unsigned char) (wCmd & 0xFF));		// Command Opcode
}

/***************************************************************************\
	MODBus I/O Utilities
\***************************************************************************/

/*=========================================================================*\
	Read Coils (Output or Input)
\*=========================================================================*/

/*** BeginHeader mmCoilRd */
int mmCoilRd(unsigned,unsigned,unsigned,unsigned,void *);
/*** EndHeader */
					
nodebug
int mmCoilRd(unsigned wAddr, unsigned wCmd, unsigned wCoil,
             unsigned wCount, void *pCoils)
{
	auto int nErr;

	if(!wAddr)
	{
		nErr = MM_NOBROAD;				//	Broadcast Not Supported
	}
	else
	{
		nErr = MM_BUSY;
		costate
		{
			mmCmdNew(wAddr, wCmd);		//	Start New Command
			mmCmdWord(wCoil);				//	Coil Address
			mmCmdWord(wCount);			//	Coil Count
			waitfor(nErr = mmExec());	//	Finish & Process Packet
			if(nErr == MM_OK)				//	Process Reply if Valid
				memcpy(pCoils, &acMMRep[3], (size_t) acMMRep[2]);
		}
	}
	return nErr;
}

/*=========================================================================*\
	Register Copy Utility
\*=========================================================================*/

/*** BeginHeader mmRegExt */
void mmRegExt(unsigned *);
/*** EndHeader */

nodebug
void mmRegExt(unsigned *pRegs)
{
	auto unsigned wCount;
	auto unsigned wData;

	wCount = acMMRep[2] >> 1;					//	Register Read Count
	for(wData = 3; wCount--; wData += 2)	//	Store Each Register Word
		*pRegs++ = mmRepWord(wData);
}

/*=========================================================================*\
	Read Registers (Input or Holding)
\*=========================================================================*/

/*** BeginHeader mmRegRd */
int mmRegRd(unsigned,unsigned,unsigned,unsigned,void *);
/*** EndHeader */

nodebug
int mmRegRd(unsigned wAddr, unsigned wCmd, unsigned wReg,
            unsigned wCount, void *pRegs)
{
	auto int nErr;

	if(!wAddr)
	{
		nErr = MM_NOBROAD;				//	Broadcast Not Supported
	}
	else
	{
		nErr = MM_BUSY;
		costate
		{
			mmCmdNew(wAddr, wCmd);		//	Start New Command
			mmCmdWord(wReg);				//	Register Address
			mmCmdWord(wCount);			//	Register Count
			waitfor(nErr = mmExec());	//	Finish & Process Packet
			if(nErr == MM_OK)				//	Process Reply if Valid
				mmRegExt(pRegs);
		}
	}
	return nErr;
}

/*=========================================================================*\
	Write Registers (No Reply)
\*=========================================================================*/

/*** BeginHeader mmRegWr */
int mmRegWr(unsigned,unsigned,unsigned *);
/*** EndHeader */

nodebug
int mmRegWr(unsigned wReg, unsigned wCount, unsigned *pRegs)
{
	auto int nErr;

	nErr = MM_BUSY;
	costate
	{
		mmCmdWord(wReg);												//	Register Address
		mmCmdWord(wCount);											//	Register Count
		mmCmdByte((unsigned char) ((2 * wCount) & 0xFF));	//	Data Byte Count
		while(wCount--)												//	Register Data
			mmCmdWord(*pRegs++);
		waitfor(nErr = mmExec());									//	Finish&Exec Packet
	}
	return nErr;
}

/***************************************************************************\
	MODBus Commands
\***************************************************************************/

/*=========================================================================*\
	[0x01] Read Coil Status
\*=========================================================================*/

/*** BeginHeader mmOutRd */
int mmOutRd(unsigned,unsigned,unsigned,void *);
/*** EndHeader */

/* START FUNCTION DESCRIPTION *****************************************
mmOutRd                       <MM_RAB.LIB>

NOTE: MM_RAB.LIB functions are generally not reentrant.

SYNTAX: int mmOutRd(unsigned wAddr, unsigned wCoil, unsigned wCount,
                    void *pCoils)

DESCRIPTION: Modbus Master query 0x01, Read Coil Status. Reads the
status (ON == 1, OFF == 0) of discrete outputs (coils, 0X references)
in the slave device. Places the present state of the selected output
coils into the buffer pointed to by *pCoils, one coil per bit with the
starting coil number in the least significant bit of the buffer's first
byte. The buffer size should be no less than 'ceil(wCount / 8.0)'
bytes. If wCount is not evenly divisible by eight the unused bits in
the last required byte are cleared to zero.

PARAMETER1: slave address, broadcast (0x00) is not supported.
PARAMETER2: starting 0X coil number (zero based).
PARAMETER3: coils count (one based).
PARAMETER4: coil information buffer pointer.

RETURN VALUE: 0 (MM_BUSY) if busy, -1 (MM_OK) if success, or exception
code (from master if < -1 or from slave if > 0). See the MM_* and MS_*
definitions near the start of MM_RAB.LIB for the complete list.
END DESCRIPTION ******************************************************/

nodebug
int mmOutRd(unsigned wAddr, unsigned wCoil, unsigned wCount,
            void *pCoils)
{
	return mmCoilRd(wAddr, 0x01, wCoil, wCount, pCoils);
}

/*=========================================================================*\
	[0x02] Read Input Status
\*=========================================================================*/

/*** BeginHeader mmIn */
int mmIn(unsigned,unsigned,unsigned,void *);
/*** EndHeader */

/* START FUNCTION DESCRIPTION *****************************************
mmIn                          <MM_RAB.LIB>