yaMBSiavr.h

#ifndef yaMBIavr_H
#define yaMBIavr_H
#endif
/************************************************************************
Title:    Yet another (small) Modbus (server) implementation for the avr.
Author:   Max Brueggemann
Hardware: any AVR with hardware UART, tested on Atmega 88/168 at 20Mhz
License:  BSD-3-Clause

LICENSE:

Copyright 2017 Max Brueggemann, www.maxbrueggemann.de

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice,
this list of conditions and the following disclaimer.

2. Redistributions in binary form must reproduce the above copyright notice,
this list of conditions and the following disclaimer in the documentation
and/or other materials provided with the distribution.

3. Neither the name of the copyright holder nor the names of its contributors
may be used to endorse or promote products derived from this software without
specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
THE POSSIBILITY OF SUCH DAMAGE.
    
************************************************************************/

/** 
 *  @code #include <yaMBSIavr.h> @endcode
 * 
 *  @brief   Interrupt-based Modbus implementation for small avr microcontrollers.
 *           The Modbus implementation guidelines at modbus.org call for response
 *           timeouts in the range of several seconds , hence only timing critical
 *           parts have been implemented within ISRs. The actual handling of the Modbus
 *           frame can easily be done in the main while loop.
 *
 *  @author Max Brueggemann www.maxbrueggemann.de
 */

/* define baudrate of modbus */
//#define BAUD 38400L 
//#define BAUD 11200L 
#define BAUD 9600L // see at Baud too - next lines
/*
* Definitions for transceiver enable pin.
*/
#define TRANSCEIVER_ENABLE_PORT PORTD
#define TRANSCEIVER_ENABLE_PIN 2
#define TRANSCEIVER_ENABLE_PORT_DDR DDRD

/**
 * @brief    
 *           At the moment the user has to set the value for Baudrate and
 *           speed mode manually. The values depend on the operating frequency 
 *           of your AVR and can be found in its datasheet.
 */
#if defined(__AVR_ATtiny2313__)
#define UART_TRANSMIT_COMPLETE_INTERRUPT USART_TX_vect
#define UART_RECEIVE_INTERRUPT   USART_RX_vect
#define UART_TRANSMIT_INTERRUPT  USART_UDRE_vect
#define UART_STATUS   UCSRA
#define UART_CONTROL  UCSRB
#define UART_DATA     UDR
#define UART_UDRIE    UDRIE

#elif defined(__AVR_ATmega164P__)
#define UART_TRANSMIT_COMPLETE_INTERRUPT USART1_TX_vect
#define UART_RECEIVE_INTERRUPT   USART1_RX_vect
#define UART_TRANSMIT_INTERRUPT  USART1_UDRE_vect
#define UART_STATUS   UCSR1A
#define UART_CONTROL  UCSR1B
#define UART_DATA     UDR1
#define UART_UDRIE    UDRIE1
#define UCSRC UCSR1C
#define RXCIE RXCIE1
#define TXCIE TXCIE1
#define RXEN RXEN1
#define TXEN TXEN1
#define UCSZ0 UCSZ10
#define U2X U2X1
#define UBRRH UBRR1H
#define UBRRL UBRR1L

#elif defined(__AVR_ATmega168PA__)|(__AVR_ATmega88PA__)|(__AVR_ATmega328PA__)|(__AVR_ATmega328P__)
#define UART_TRANSMIT_COMPLETE_INTERRUPT USART_TX_vect
#define UART_RECEIVE_INTERRUPT   USART_RX_vect
#define UART_TRANSMIT_INTERRUPT  USART_UDRE_vect
#define UART_STATUS   UCSR0A
#define UART_CONTROL  UCSR0B
#define UART_DATA     UDR0
#define UART_UDRIE    UDRIE0
#define UCSRC UCSR0C
#define RXCIE RXCIE0
#define TXCIE TXCIE0
#define RXEN RXEN0
#define TXEN TXEN0
#define UCSZ0 UCSZ00
#define U2X U2X0
#define UBRRH UBRR0H
#define UBRRL UBRR0L
/*
 * Change this value if you are using a different frequency and/or
 * different baudrate.
*/
//#define Baud 64 //38400@20e6Hz, Ubrr=Fosc/(8*baud)-1, 16000000/(8*9600)-1=207
//#define Baud 177 //11200@16e6Hz
#define Baud 207 // 9600@16e6Hz

#elif defined(__AVR_ATtiny441__)
#define UART_TRANSMIT_COMPLETE_INTERRUPT USART0_TX_vect
#define UART_RECEIVE_INTERRUPT   USART0_RX_vect
#define UART_TRANSMIT_INTERRUPT  USART0_UDRE_vect
#define UART_STATUS   UCSR0A
#define UART_CONTROL  UCSR0B
#define UART_DATA     UDR0
#define UART_UDRIE    UDRIE0
#define UCSRC UCSR0C
#define RXCIE RXCIE0
#define TXCIE TXCIE0
#define RXEN RXEN0
#define TXEN TXEN0
#define UCSZ0 UCSZ00
#define U2X U2X0
#define UBRRH UBRR0H
#define UBRRL UBRR0L

#elif defined(__AVR_ATmega8__)|| defined(__AVR_ATmega16__) || defined(__AVR_ATmega32__) || defined(__AVR_ATmega323__)
#define UART_TRANSMIT_COMPLETE_INTERRUPT USART_TXC_vect
#define UART_RECEIVE_INTERRUPT   USART_RXC_vect
#define UART_TRANSMIT_INTERRUPT  USART_UDRE_vect
#define UART_STATUS   UCSRA
#define UART_CONTROL  UCSRB
#define UART_DATA     UDR
#define UART_UDRIE    UDRIE

#else
#error "no definition available"
#endif

#ifndef F_CPU
#error " F_CPU not defined "
#else
   #define UBRR (F_CPU / 8 / BAUD ) -1 
#endif /* F_CPU */
/*
 * Available address modes.
*/
#define MULTIPLE_ADR 2
#define SINGLE_ADR 1

/*
* Use SINGLE_ADR or MULTIPLE_ADR, default: SINGLE_ADR
* This is useful for building gateways, routers or clients that for whatever reason need multiple addresses.
*/
#define ADDRESS_MODE SINGLE_ADR

/*
* Use 485 or 232, default: 485
* Use 232 for testing purposes or very simple applications that do not require RS485 and bus topology.
*/
#define PHYSICAL_TYPE 485 //possible values: 485, 232

/*
#define modbusBaudrate 38400
#define modbusBlocksize 10
#define modbusBlockTime ((float)modbusBlocksize*1000000)/((float) modbusBaudrate) //is 260 für 38400
#define timerISROccurenceTime 102

#define TimeoutStartOfMessage  (uint16_t)(modbusBlockTime*3.5/(float)timerISROccurenceTime)
#define TimeoutEndOfMessage (uint16_t)(modbusBlockTime*4/(float)timerISROccurenceTime)
#define ReceiveMaxGap  (uint16_t)(modbusBlockTime*1.5/(float)timerISROccurenceTime)
*/
#define modbusInterFrameDelayReceiveStart 16
#define modbusInterFrameDelayReceiveEnd 18
#define modbusInterCharTimeout 7

/**
 * @brief    Defines the maximum Modbus frame size accepted by the device. 255 is the default
 *           and also the maximum value. However, it might be useful to set this to lower
 *           values, with 8 being the lowest possible value, in order to save on ram space.
 */
#define MaxFrameIndex 255

/**
 * @brief    Modbus Function Codes
 *           Refer to modbus.org for further information.
 *           It's good practice to return exception code 01 in case you receive a function code
 *           that you haven't implemented in your application.
 */
#define fcReadCoilStatus 1 //read single/multiple coils
#define fcReadInputStatus 2 //read single/multiple inputs
#define fcReadHoldingRegisters 3 //read analog output registers
#define fcReadInputRegisters 4 //read analog input registers (2 Bytes per register)
#define fcForceSingleCoil 5 //write single bit
#define fcPresetSingleRegister 6 //write analog output register (2 Bytes)
#define fcForceMultipleCoils 15 //write multiple bits
#define fcPresetMultipleRegisters 16 //write multiple analog output registers (2 Bytes each)
#define fcReportSlaveID 17 //read device description, run status and other device specific information

/**
 * @brief    Modbus Exception Codes
 *           Refer to modbus.org for further information.
 *           It's good practice to return exception code 01 in case you receive a function code
 *           that you haven't implemented in your application.
 */
#define ecIllegalFunction 1 
#define ecIllegalDataAddress 2 
#define ecIllegalDataValue 3
#define ecSlaveDeviceFailure 4
#define ecAcknowledge 5
#define ecSlaveDeviceBusy 6
#define ecNegativeAcknowledge 7
#define ecMemoryParityError 8

/**
 * @brief    Internal bit definitions
 */
#define BusTimedOut 0
#define Receiving 1
#define Transmitting 2
#define ReceiveCompleted 3
#define TransmitRequested 4
#define TimerActive 5
#define GapDetected 6

/**
* @brief    Configures the UART. Call this function only once.
*/
extern void modbusInit(void);

/**
* @brief    receive/transmit data array
*/
volatile unsigned char rxbuffer[MaxFrameIndex+1];

/**
* @brief    Current receive/transmit position
*/
volatile uint16_t DataPos;

/**
 * This only applies to single address mode.
 */
#if ADDRESS_MODE == SINGLE_ADR
	/**
	* @brief: Read the device address   
	*/
	extern uint8_t modbusGetAddress(void);

	/**
	* @brief: Set the device address
	*         Arguments: - newadr: the new device address
	*/
	extern void modbusSetAddress(unsigned char newadr);
#endif

/* @brief: Sends a response.
*
*         Arguments: - packtop, index of the last byte in rxbuffer
*                      that contains payload. Maximum value is
*				       MaxFrameIndex-2.
*/
extern void modbusSendMessage(unsigned char packtop);

/* @brief: Sends a Modbus exception.
*
*         Arguments: - exceptionCode
*/
extern void modbusSendException(unsigned char exceptionCode);

/* @brief: Discards the current transaction. For MULTIPLE_ADR-mode and general
*		   testing purposes. Call this function if you don't want to reply at all.
*/
void modbusReset(void);

/**
 * @brief    Call this function whenever possible and check if its return value has the ReceiveCompleted Bit set.
 *           Preferably do this in the main while. I do not recommend calling this function within ISRs.
 * @example  if (modbusGetBusState() & (1<<ReceiveCompleted)) {
 *           modbusSendExcepton(ecIllegalFunction);
 *           }
 */
extern uint8_t modbusGetBusState(void);

/**
 * @brief    Call every 100µs using a timer ISR.
 */
extern void modbusTickTimer(void);

/**
 * @brief    Returns amount of bits/registers requested.
 */
extern uint16_t modbusRequestedAmount(void);

/**
 * @brief    Returns the address of the first requested bit/register.
 */
extern uint16_t modbusRequestedAddress(void);

/* A fairly simple and hopefully Modbus compliant 16 Bit CRC algorithm.
*  Returns 1 if the crc check is positive, returns 0 if it fails.
*  Appends two crc bytes to the array.
*/
extern uint8_t crc16(volatile uint8_t *ptrToArray,uint8_t inputSize);

/* @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)
*
*/
extern uint8_t modbusExchangeBits(volatile uint8_t *ptrToInArray, uint16_t startAddress, uint16_t size);

/* @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)
*
*/
extern uint8_t modbusExchangeRegisters(volatile uint16_t *ptrToInArray, uint16_t startAddress, uint16_t size);