modbus.h

// Copyright (c) 2024, Myriota Pty Ltd, All Rights Reserved
// SPDX-License-Identifier: BSD-3-Clause-Attribution
//
// This file is licensed under the BSD with attribution  (the "License"); you
// may not use these files except in compliance with the License.
//
// You may obtain a copy of the License here:
// LICENSE-BSD-3-Clause-Attribution.txt and at
// https://spdx.org/licenses/BSD-3-Clause-Attribution.html
//
// See the License for the specific language governing permissions and
// limitations under the License.
 
#ifndef MYRIOTA_MODBUS_H
#define MYRIOTA_MODBUS_H
 
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include <sys/types.h>


typedef enum {
  MODBUS_SUCCESS = 0,
  MODBUS_ERROR_EXCEPTION_ILLEGAL_FUNCTION = 0x01,
  MODBUS_ERROR_EXCEPTION_ILLEGAL_DATA_ADDRESS = 0x02,
  MODBUS_ERROR_EXCEPTION_ILLEGAL_DATA_VALUE = 0x03,
  MODBUS_ERROR_EXCEPTION_SLAVE_DEVICE_FAILURE = 0x04,
  MODBUS_ERROR_EXCEPTION_ACKNOWLEDGE = 0x05,
  MODBUS_ERROR_EXCEPTION_SLAVE_DEVICE_BUSY = 0x06,
  MODBUS_ERROR_EXCEPTION_NEGATIVE_ACKNOWLEDGMENT = 0x07,
  MODBUS_ERROR_EXCEPTION_MEMORY_PARITY_ERROR = 0x08,
  MODBUS_ERROR_EXCEPTION_GATEWAY_PATH_UNAVAILABLE = 0x0A,
  MODBUS_ERROR_EXCEPTION_GATEWAY_TARGET_DEVICE_FAILED_TO_RESPOND = 0x0B,
  MODBUS_ERROR_INVALID_HANDLE,
  MODBUS_ERROR_INVALID_CRC16,
  MODBUS_ERROR_MALFORMED_RESPONSE,
  MODBUS_ERROR_RESPONSE_FROM_WRONG_SLAVE_ADDRESS,
  MODBUS_ERROR_IO_FAILURE,
  MODBUS_ERROR_BAD_STATE,
  MODBUS_ERROR_OVERFLOW,
} MYRIOTA_ModbusErrors;

typedef uint8_t MYRIOTA_ModbusHandle;

typedef uint8_t MYRIOTA_ModbusDeviceAddress;

typedef uint16_t MYRIOTA_ModbusDataAddress;

typedef int (*MYRIOTA_ModbusSerialInterfaceInitFn_t)(void *const ctx);

typedef void (*MYRIOTA_ModbusSerialInterfaceDeinitFn_t)(void *const ctx);

typedef ssize_t (*MYRIOTA_ModbusSerialInterfaceReadFn_t)(void *const ctx, uint8_t *const buffer,
  const size_t count);

typedef ssize_t (*MYRIOTA_ModbusSerialInterfaceWriteFn_t)(void *const ctx,
  const uint8_t *const buffer, const size_t count);

typedef struct {
  void *ctx;
  MYRIOTA_ModbusSerialInterfaceInitFn_t init;
  MYRIOTA_ModbusSerialInterfaceDeinitFn_t deinit;
  MYRIOTA_ModbusSerialInterfaceReadFn_t read;
  MYRIOTA_ModbusSerialInterfaceWriteFn_t write;
} MYRIOTA_ModbusSerialInterface;

typedef enum {
  MODBUS_FRAMING_MODE_RTU,
} MYRIOTA_ModbusFramingMode;

typedef struct {
  MYRIOTA_ModbusFramingMode framing_mode;
  MYRIOTA_ModbusSerialInterface serial_interface;
} MYRIOTA_ModbusInitOptions;

MYRIOTA_ModbusHandle MYRIOTA_ModbusInit(const MYRIOTA_ModbusInitOptions options);

void MYRIOTA_ModbusDeinit(const MYRIOTA_ModbusHandle handle);

int MYRIOTA_ModbusEnable(const MYRIOTA_ModbusHandle handle);

int MYRIOTA_ModbusDisable(const MYRIOTA_ModbusHandle handle);

void MYRIOTA_ModbusBytesSetBit(uint8_t *const bytes, const size_t count, const uint8_t bit_index,
  const bool value);

void MYRIOTA_ModbusBytesGetBit(const uint8_t *const bytes, const size_t count,
  const uint8_t bit_index, bool *const value);

int MYRIOTA_ModbusReadCoils(const MYRIOTA_ModbusHandle handle,
  const MYRIOTA_ModbusDeviceAddress slave, const MYRIOTA_ModbusDataAddress addr, const size_t count,
  uint8_t *const bytes);

int MYRIOTA_ModbusReadDiscreteInputs(const MYRIOTA_ModbusHandle handle,
  const MYRIOTA_ModbusDeviceAddress slave, const MYRIOTA_ModbusDataAddress addr, const size_t count,
  uint8_t *const bytes);

int MYRIOTA_ModbusReadHoldingRegisters(const MYRIOTA_ModbusHandle handle,
  const MYRIOTA_ModbusDeviceAddress slave, const MYRIOTA_ModbusDataAddress addr, const size_t count,
  uint8_t *const bytes);

int MYRIOTA_ModbusReadInputRegisters(const MYRIOTA_ModbusHandle handle,
  const MYRIOTA_ModbusDeviceAddress slave, const MYRIOTA_ModbusDataAddress addr, const size_t count,
  uint8_t *const bytes);

int MYRIOTA_ModbusWriteCoil(const MYRIOTA_ModbusHandle handle,
  const MYRIOTA_ModbusDeviceAddress slave, const MYRIOTA_ModbusDataAddress addr,
  const uint16_t word);

int MYRIOTA_ModbusWriteHoldingRegister(const MYRIOTA_ModbusHandle handle,
  const MYRIOTA_ModbusDeviceAddress slave, const MYRIOTA_ModbusDataAddress addr,
  const uint16_t word);

int MYRIOTA_ModbusWriteCoils(const MYRIOTA_ModbusHandle handle,
  const MYRIOTA_ModbusDeviceAddress slave, const MYRIOTA_ModbusDataAddress addr, const size_t count,
  const uint8_t *const bytes);

int MYRIOTA_ModbusWriteHoldingRegisters(const MYRIOTA_ModbusHandle handle,
  const MYRIOTA_ModbusDeviceAddress slave, const MYRIOTA_ModbusDataAddress addr, const size_t count,
  const uint8_t *const bytes);

 
#endif /* MYRIOTA_MODBUS_H */