#include <avr/io.h>
#include <avr/interrupt.h>
#include "ModBusSlave.h"
#include "Macro.h"
volatile uint8_t BusState = 0;
volatile uint16_t modbusTimer = 0;
volatile uint8_t rxbuffer[MaxFrameIndex+1];
volatile uint16_t DataPos = 0;
volatile uint8_t PacketTopIndex = 7;
volatile uint8_t modBusStaMaStates = 0;
uint8_t modbusGetBusState(void)
{
return BusState;
}
#if ADDRESS_MODE == SINGLE_ADR
volatile uint8_t Address = 0x00;
uint8_t modbusGetAddress(void)
{
return Address;
}
void modbusSetAddress(uint8_t newadr)
{
Address = newadr;
}
#endif
#if PHYSICAL_TYPE == 485
void transceiver_txen(void)
{
TRANSCEIVER_ENABLE_PORT|=(1<<TRANSCEIVER_ENABLE_PIN);
}
void transceiver_rxen(void)
{
TRANSCEIVER_ENABLE_PORT&=~(1<<TRANSCEIVER_ENABLE_PIN);
}
#endif
/* @brief: A fairly simple Modbus compliant 16 Bit CRC algorithm.
*
* Returns 1 if the crc check is positive, returns 0 and saves the calculated CRC bytes
* at the end of the data array if it fails.
*
*/
uint8_t crc16(volatile uint8_t *ptrToArray,uint8_t inputSize) //A standard CRC algorithm
{
uint16_t out=0xffff;
uint16_t carry;
uint8_t n;
inputSize++;
for (int l=0; l<inputSize; l++) {
out ^= ptrToArray[l];
for (n = 0; n < 8; n++) {
carry = out & 1;
out >>= 1;
if (carry) out ^= 0xA001;
}
}
//out=0x1234;
if ((ptrToArray[inputSize]==out%256) && (ptrToArray[inputSize+1]==out/256)) //check
{
return 1;
} else {
ptrToArray[inputSize]=out%256; //append Lo
ptrToArray[inputSize+1]=out/256; //append Hi
return 0;
}
}
/* @brief: copies a single or multiple words from one array of bytes to another array of bytes
* amount must not be bigger than 255...
*
*/
void listRegisterCopy(volatile uint8_t *source, volatile uint8_t *target, uint8_t amount)
{
for (uint8_t c=0; c<amount; c++)
{
*(target+c)=*(source+c);
}
}
/* @brief: copies a single bit from one char to another char (or arrays thereof)
*
*
*/
void listBitCopy(volatile uint8_t *source, uint16_t sourceNr,volatile uint8_t *target, uint16_t targetNr)
{
if(*(source+(sourceNr/8))&(1<<(sourceNr-((sourceNr/8)*8))))
{
*(target+(targetNr/8))|=(1<<(targetNr-((targetNr/8)*8)));
} else *(target+(targetNr/8))&=~(1<<(targetNr-((targetNr/8)*8)));
}
/* @brief: Back to receiving state.
*
*/
void modbusReset(void)
{
BusState=(1<<TimerActive); //stop receiving (error)
modbusTimer=0;
}
void modbusTickTimer(void)
{
if (BusState&(1<<TimerActive))
{
modbusTimer++;
if (BusState&(1<<Receiving)) //we are in receiving mode
{
if ((modbusTimer==modbusInterCharTimeout)) {
BusState|=(1<<GapDetected);
} else if ((modbusTimer==modbusInterFrameDelayReceiveEnd)) { //end of message
BusState=(1<<ReceiveCompleted);
#if ADDRESS_MODE == MULTIPLE_ADR
if (crc16(rxbuffer,DataPos-3)) { //perform crc check only. This is for multiple/all address mode.
} else modbusReset();
#endif
#if ADDRESS_MODE == SINGLE_ADR
if (rxbuffer[0]==Address && crc16(rxbuffer,DataPos-3)) { //is the message for us? => perform crc check
} else modbusReset();
#endif
}
} else if (modbusTimer==modbusInterFrameDelayReceiveStart) BusState|=(1<<BusTimedOut);
}
}
ISR(USART_RX)
{
uint8_t data;
data = UART_DATA;
modbusTimer=0; //reset timer
if (!(BusState & (1<<ReceiveCompleted)) && !(BusState & (1<<TransmitRequested)) && !(BusState & (1<<Transmitting)) && (BusState & (1<<Receiving)) && !(BusState & (1<<BusTimedOut)))
{
if (DataPos>MaxFrameIndex) modbusReset();
else
{
rxbuffer[DataPos]=data;
DataPos++; //TODO: maybe prevent this from exceeding 255?
}
} else
if (!(BusState & (1<<ReceiveCompleted)) && !(BusState & (1<<TransmitRequested)) && !(BusState & (1<<Transmitting)) && !(BusState & (1<<Receiving)) && (BusState & (1<<BusTimedOut)))
{
rxbuffer[0]=data;
BusState=((1<<Receiving)|(1<<TimerActive));
DataPos=1;
}
}
ISR(USART_UDRE)
{
BusState&=~(1<<TransmitRequested);
BusState|=(1<<Transmitting);
UART_DATA=rxbuffer[DataPos];
DataPos++;
if (DataPos==(uint8_t)(PacketTopIndex+1)) {
UART_CONTROL&=~(1<<UART_UDRIE);
}
}
ISR(USART_TX)
{
#if PHYSICAL_TYPE == 485
transceiver_rxen();
#endif
modbusReset();
}
void modbusInit(void)
{
UBRRH = (uint8_t)((UBRR) >> 8);
UBRRL = (uint8_t) UBRR;
UART_STATUS = (1<<U2X); //double speed mode.
#ifdef URSEL // if UBRRH and UCSRC share the same I/O location , e.g. ATmega8
UCSRC = (1<<URSEL)|(3<<UCSZ0); //Frame Size
#else
UCSRC = (3<<UCSZ0); //Frame Size
#endif
UART_CONTROL = (1<<TXCIE)|(1<<RXCIE)|(1<<RXEN)|(1<<TXEN); // USART receiver and transmitter and receive complete interrupt
#if PHYSICAL_TYPE == 485
TRANSCEIVER_ENABLE_PORT_DDR|=(1<<TRANSCEIVER_ENABLE_PIN);
transceiver_rxen();
#endif
BusState=(1<<TimerActive);
}
/* @brief: Sends a response.
*
* Arguments: - packtop: Position of the last byte containing data.
* modbusSendException is a good usage example.
*/
void modbusSendMessage(uint8_t packtop)
{
PacketTopIndex=packtop+2;
crc16(rxbuffer,packtop);
BusState|=(1<<TransmitRequested);
DataPos=0;
#if PHYSICAL_TYPE == 485
transceiver_txen();
#endif
UART_CONTROL|=(1<<UART_UDRIE);
BusState&=~(1<<ReceiveCompleted);
}
/* @brief: Sends an exception response.
*
* Arguments: - exceptionCode
*
*/
void modbusSendException(uint8_t exceptionCode)
{
rxbuffer[1]|=(1<<7); //setting MSB of the function code (the exception flag)
rxbuffer[2]=exceptionCode; //Exceptioncode. Also the last byte containing data
modbusSendMessage(2);
}
/* @brief: Returns the amount of requested data objects (coils, discretes, registers)
*
*/
uint16_t modbusRequestedAmount(void)
{
return (rxbuffer[5]|(rxbuffer[4]<<8));
}
/* @brief: Returns the address of the first requested data object (coils, discretes, registers)
*
*/
uint16_t modbusRequestedAddress(void)
{
return (rxbuffer[3]|(rxbuffer[2]<<8));
}
/* @brief: copies a single or multiple bytes from one array of bytes to an array of 16-bit-words
*
*/
void intToModbusRegister(volatile uint16_t *inreg, volatile uint8_t *outreg, uint8_t amount)
{
for (uint8_t c=0; c<amount; c++)
{
*(outreg+c*2) = (uint8_t)(*(inreg+c) >> 8);
*(outreg+1+c*2) = (uint8_t)(*(inreg+c));
}
}
/* @brief: copies a single or multiple 16-bit-words from one array of integers to an array of bytes
*
*/
void modbusRegisterToInt(volatile uint8_t *inreg, volatile uint16_t *outreg, uint8_t amount)
{
for (uint8_t c=0; c<amount; c++)
{
*(outreg+c) = (*(inreg+c*2) << 8) + *(inreg+1+c*2);
}
}
/* @brief: Handles single/multiple register reading and single/multiple register writing.
*
* Arguments: - ptrToInArray: pointer to the user's data array containing registers
* - startAddress: address of the first register in the supplied array
* - size: input array size in the requested format (16bit-registers)
*
*/
uint8_t modbusExchangeRegisters(volatile uint16_t *ptrToInArray, uint16_t startAddress, uint16_t size)
{
uint16_t requestedAmount = modbusRequestedAmount();
uint16_t requestedAdr = modbusRequestedAddress();
if (rxbuffer[1]==fcPresetSingleRegister) requestedAmount=1;
if ((requestedAdr>=startAddress) && ((startAddress+size)>=(requestedAmount+requestedAdr))) {
if ((rxbuffer[1]==fcReadHoldingRegisters) || (rxbuffer[1]==fcReadInputRegisters) )
{
if ((requestedAmount*2)<=(MaxFrameIndex-4)) //message buffer big enough?
{
rxbuffer[2]=(uint8_t)(requestedAmount*2);
intToModbusRegister(ptrToInArray+(uint8_t)(requestedAdr-startAddress),rxbuffer+3,requestedAmount);
modbusSendMessage(2+rxbuffer[2]);
return 1;
} else modbusSendException(ecIllegalDataValue);
}
else if (rxbuffer[1]==fcPresetMultipleRegisters)
{
if (((rxbuffer[6])>=requestedAmount*2) && ((DataPos-9)>=rxbuffer[6])) //enough data received?
{
modbusRegisterToInt(rxbuffer+7,ptrToInArray+(uint8_t)(requestedAdr-startAddress),(uint8_t)(requestedAmount));
modbusSendMessage(5);
return 1;
} else modbusSendException(ecIllegalDataValue);//too few data bytes received
}
else if (rxbuffer[1]==fcPresetSingleRegister)
{
modbusRegisterToInt(rxbuffer+4,ptrToInArray+(uint8_t)(requestedAdr-startAddress),1);
modbusSendMessage(5);
return 1;
}
//modbusSendException(ecSlaveDeviceFailure); //inapropriate call of modbusExchangeRegisters
return 0;
} else {
modbusSendException(ecIllegalDataValue);
return 0;
}
}
/* @brief: Handles single/multiple input/coil reading and single/multiple coil writing.
*
* Arguments: - ptrToInArray: pointer to the user's data array containing bits
* - startAddress: address of the first bit in the supplied array
* - size: input array size in the requested format (bits)
*
*/
uint8_t modbusExchangeBits(volatile uint8_t *ptrToInArray, uint16_t startAddress, uint16_t size)
{
uint16_t requestedAmount = modbusRequestedAmount();
uint16_t requestedAdr = modbusRequestedAddress();
if (rxbuffer[1]==fcForceSingleCoil) requestedAmount=1;
if ((requestedAdr>=startAddress) && ((startAddress+size)>=(requestedAmount+requestedAdr)))
{
if ((rxbuffer[1]==fcReadInputStatus) || (rxbuffer[1]==fcReadCoilStatus))
{
if (requestedAmount<=((MaxFrameIndex-4)*8)) //message buffer big enough?
{
rxbuffer[2]=(requestedAmount/8);
if (requestedAmount%8>0)
{
rxbuffer[(uint8_t)(requestedAmount/8)+3]=0x00; //fill last data byte with zeros
rxbuffer[2]++;
}
for (uint16_t c = 0; c<requestedAmount; c++)
{
listBitCopy(ptrToInArray,requestedAdr-startAddress+c,rxbuffer+3,c);
}
modbusSendMessage(rxbuffer[2]+2);
return 1;
} else modbusSendException(ecIllegalDataValue); //too many bits requested within single request
}
else if (rxbuffer[1]==fcForceMultipleCoils)
{
if (((rxbuffer[6]*8)>=requestedAmount) && ((DataPos-9)>=rxbuffer[6])) //enough data received?
{
for (uint16_t c = 0; c<requestedAmount; c++)
{
listBitCopy(rxbuffer+7,c,ptrToInArray,requestedAdr-startAddress+c);
}
modbusSendMessage(5);
return 1;
} else modbusSendException(ecIllegalDataValue);//exception too few data bytes received
}
else if (rxbuffer[1]==fcForceSingleCoil) {
listBitCopy(rxbuffer+4,0,ptrToInArray,requestedAdr-startAddress);
modbusSendMessage(5);
return 1;
}
//modbusSendException(ecSlaveDeviceFailure); //inanpropriate call of modbusExchangeBits
return 0;
} else
{
modbusSendException(ecIllegalDataValue);
return 0;
}
}
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