nBus-bridge-core/Src/NbusBridge.cpp

/**
 * @file NbusBridge.cpp
 * @brief Implementation of  nBus Brige
 * @date Jun 23, 2026
 * @author Juraj Dudak, Matus Necas
 */

#include "NbusBridge.h"


static const uint8_t __crc8x_table[] = {
    0x00, 0x07, 0x0E, 0x09, 0x1C, 0x1B, 0x12, 0x15, 0x38, 0x3F, 0x36, 0x31, 0x24, 0x23, 0x2A, 0x2D, 0x70, 0x77, 0x7E,
    0x79, 0x6C, 0x6B, 0x62, 0x65, 0x48, 0x4F, 0x46, 0x41, 0x54, 0x53, 0x5A, 0x5D, 0xE0, 0xE7, 0xEE, 0xE9, 0xFC, 0xFB,
    0xF2, 0xF5, 0xD8, 0xDF, 0xD6, 0xD1, 0xC4, 0xC3, 0xCA, 0xCD, 0x90, 0x97, 0x9E, 0x99, 0x8C, 0x8B, 0x82, 0x85, 0xA8,
    0xAF, 0xA6, 0xA1, 0xB4, 0xB3, 0xBA, 0xBD, 0xC7, 0xC0, 0xC9, 0xCE, 0xDB, 0xDC, 0xD5, 0xD2, 0xFF, 0xF8, 0xF1, 0xF6,
    0xE3, 0xE4, 0xED, 0xEA, 0xB7, 0xB0, 0xB9, 0xBE, 0xAB, 0xAC, 0xA5, 0xA2, 0x8F, 0x88, 0x81, 0x86, 0x93, 0x94, 0x9D,
    0x9A, 0x27, 0x20, 0x29, 0x2E, 0x3B, 0x3C, 0x35, 0x32, 0x1F, 0x18, 0x11, 0x16, 0x03, 0x04, 0x0D, 0x0A, 0x57, 0x50,
    0x59, 0x5E, 0x4B, 0x4C, 0x45, 0x42, 0x6F, 0x68, 0x61, 0x66, 0x73, 0x74, 0x7D, 0x7A, 0x89, 0x8E, 0x87, 0x80, 0x95,
    0x92, 0x9B, 0x9C, 0xB1, 0xB6, 0xBF, 0xB8, 0xAD, 0xAA, 0xA3, 0xA4, 0xF9, 0xFE, 0xF7, 0xF0, 0xE5, 0xE2, 0xEB, 0xEC,
    0xC1, 0xC6, 0xCF, 0xC8, 0xDD, 0xDA, 0xD3, 0xD4, 0x69, 0x6E, 0x67, 0x60, 0x75, 0x72, 0x7B, 0x7C, 0x51, 0x56, 0x5F,
    0x58, 0x4D, 0x4A, 0x43, 0x44, 0x19, 0x1E, 0x17, 0x10, 0x05, 0x02, 0x0B, 0x0C, 0x21, 0x26, 0x2F, 0x28, 0x3D, 0x3A,
    0x33, 0x34, 0x4E, 0x49, 0x40, 0x47, 0x52, 0x55, 0x5C, 0x5B, 0x76, 0x71, 0x78, 0x7F, 0x6A, 0x6D, 0x64, 0x63, 0x3E,
    0x39, 0x30, 0x37, 0x22, 0x25, 0x2C, 0x2B, 0x06, 0x01, 0x08, 0x0F, 0x1A, 0x1D, 0x14, 0x13, 0xAE, 0xA9, 0xA0, 0xA7,
    0xB2, 0xB5, 0xBC, 0xBB, 0x96, 0x91, 0x98, 0x9F, 0x8A, 0x8D, 0x84, 0x83, 0xDE, 0xD9, 0xD0, 0xD7, 0xC2, 0xC5, 0xCC,
    0xCB, 0xE6, 0xE1, 0xE8, 0xEF, 0xFA, 0xFD, 0xF4, 0xF3};


NbusBridge::NbusBridge(NbusCommunicator *nbus_communicator)
: _communicator(nbus_communicator)
{

}

void NbusBridge::scanNetwork()
{
    _communicator->setLedOn();

    _num_slaves = 0;

    uint8_t   *response_raw;
    Nbus_PDU_t  pdu = {NBUS_BROADCAST_ADDRESS, NBUS_BROADCAST_ADDRESS, FC_ECHO};
    uint8_t    data[] = {NBUS_BRIDGE_ECHO_SCAN_BYTE0, NBUS_BRIDGE_ECHO_SCAN_BYTE1, NBUS_BRIDGE_ECHO_SCAN_BYTE2, NBUS_BRIDGE_ECHO_SCAN_BYTE3};

    for (uint32_t i = 0; i < NBUS_BRIDGE_MAX_SLAVES; i++)
    {
        _slaves[i].setModuleAddress(0);
    }

    for (uint32_t i = 1; i < NBUS_BRIDGE_MAX_SLAVES; i++)
    {
        _communicator->toggleLed();
        pdu.ma = i;
        _worker_frame_ptr = _communicator->sendAndReceiveSlave(_makePacket(pdu, data, NBUS_BRIDGE_ECHO_SCAN_SIZE));

        if (!_worker_frame_ptr->IsEmpty())
        {
            response_raw = _worker_frame_ptr->GetFrame();

            if (NBUS_TX_DATA0(response_raw + 0) == NBUS_BRIDGE_ECHO_SCAN_BYTE0 && NBUS_TX_DATA0(response_raw + 1) == NBUS_BRIDGE_ECHO_SCAN_BYTE1 &&
            	NBUS_TX_DATA0(response_raw + 2) == NBUS_BRIDGE_ECHO_SCAN_BYTE2 && NBUS_TX_DATA0(response_raw + 3) == NBUS_BRIDGE_ECHO_SCAN_BYTE3)
            {
                _slaves[_num_slaves].setModuleAddress(i);
                _slaves[_num_slaves].setCommunicator(_communicator);
                _slaves[_num_slaves].cmdGetSensorCnt(true); 	// retrieve sensor count for each slave
                _num_slaves++;
            }
        }
    }

    _communicator->setLedOff();
}

void NbusBridge::processRequest(uint8_t *rxFrame, uint8_t size)
{
    uint8_t crcC = _crc8x_fast(rxFrame, size - 1);

    if (crcC != NBUS_RX_CRC8(rxFrame, size))
    {
        return;
    }

    _pdu.ma = rxFrame[0];
    _pdu.sa = rxFrame[1];
    _pdu.fc = (Nbus_FC_e)rxFrame[2];

    if (_pdu.ma == NBUS_BROADCAST_ADDRESS)
    {
        if (_pdu.sa == NBUS_BRIDGE_ADDRESS)
        {
            _processBridgeRequest(rxFrame, size);
        }
        else
        {
            _processBroadcast(rxFrame, size);
        }
    }
    else
    {
        _processSlaveRequest(rxFrame, size);
    }
}

void NbusBridge::processRunningState()
{
    if (_run_state == STATE_STOPPED)
    {
        return;
    }

    if (_run_state == STATE_TO_STOP)
    {
        _communicator->setLedOff();
        _run_state = STATE_STOPPED;
        return;
    }

    _communicator->setLedOn();

    _worker_frame_ptr = _makeBridgeDataPacket();

    if (_run_state == STATE_RUNNING)
    {
        _communicator->sendToMaster(_worker_frame_ptr);
    }
}

uint8_t NbusBridge::_crc8x_fast(void const *mem, uint16_t len)
{
    uint8_t crc = 0;
    uint8_t const *data = (uint8_t *)mem;
    if (data == nullptr)
        return 0xff;
    crc &= 0xff;
    while (len--)
        crc = __crc8x_table[crc ^ *data++];
    return crc;
}

void NbusBridge::_processBroadcast(uint8_t *rx_frame, uint8_t size)
{
    _communicator->sendToSlave(_forwardPacket(rx_frame, size));
}

void NbusBridge::_processBridgeRequest(uint8_t *rx_frame, uint8_t size)
{
	switch (NBUS_RX_FUNCTION_CODE(rx_frame))
    {
    case FC_ECHO:				/* GET 1 */
    	_worker_frame_ptr = _forwardPacket(rx_frame, size);
    	break;

    case NBUS_SET_CMD(FC_STOP):  /* SET 2 */
    	_cmdSetStop();
    	_worker_frame_ptr = nullptr;
    	break;

    case NBUS_SET_CMD(FC_START): /* SET 3 */
    	_cmdSetStart();
  		_worker_frame_ptr = nullptr;
    	break;

    case NBUS_SET_CMD(FC_RESET): /* SET 9 */
		scanNetwork();
        _worker_frame_ptr = _rspSetStatus(STATUS_SUCCESS);
        break;

    case FC_DATA:           	/* GET 11 */
    	_worker_frame_ptr = _cmdGetData();
    	break;

    case FC_INFO:           	/* GET 14 */
    	_worker_frame_ptr = _cmdGetInfo();
        break;

    case FC_SENSOR_FORMAT: 		/* GET 15 */
       	_worker_frame_ptr = _cmdGetFormat();
        break;

    case FC_SLAVES: 			/* GET 16 */
       	_worker_frame_ptr = _cmdGetSlaves();
        break;

    default:
      	_worker_frame_ptr = _rspSetError(ILLEGAL_FUNCTION);
    }

	_communicator->sendToMaster(_worker_frame_ptr);
}

void NbusBridge::_processSlaveRequest(uint8_t *rx_frame, uint8_t size)
{
    uint8_t module_address = NBUS_RX_MODULE_ADDRESS(rx_frame);
    bool valid_slave = true;

    for (uint32_t i = 0; i < _num_slaves; i++)
    {
    	if (module_address == _slaves[i].getModuleAddress())
    	{
    		valid_slave = false;
    	}
    }

    if (valid_slave)
    {
    	_worker_frame_ptr = _communicator->sendAndReceiveSlave(_forwardPacket(rx_frame, size));

    }
    else
    {
    	_worker_frame_ptr = _rspSetError(ILLEGAL_DEVICE_ADDRESS);
    }

    _communicator->sendToMaster(_worker_frame_ptr);
}

DataFrame* NbusBridge::_cmdGetData()
{
	_default_frame.Init();
	_default_frame.AddUint8(NBUS_BROADCAST_ADDRESS);
	_default_frame.AddUint8(NBUS_BRIDGE_ADDRESS);
	_default_frame.AddUint8((Nbus_FC_e)FC_DATA);
	_addDataPayload(&_default_frame);
	_default_frame.Commit();

	return &_default_frame;
}

DataFrame * NbusBridge::_cmdGetInfo()
{
	_default_frame.Init();
	_default_frame.AddUint8(NBUS_BROADCAST_ADDRESS);
	_default_frame.AddUint8(NBUS_BRIDGE_ADDRESS);
	_default_frame.AddUint8(FC_INFO);
	_default_frame.AddArray((uint8_t*)NBUS_BRIDGE_INFO_VERSION, 3);
	_default_frame.AddArray((uint8_t*)NBUS_BRIDGE_INFO_HW_FAMILY, 3);
	_default_frame.AddArray((uint8_t*)NBUS_BRIDGE_INFO_HW_VERSION, 3);
	_default_frame.Commit();

	return &_default_frame;
}

DataFrame * NbusBridge::_cmdGetFormat()
{
	_default_frame.Init();
	_default_frame.AddUint8(NBUS_BROADCAST_ADDRESS);
	_default_frame.AddUint8(NBUS_BRIDGE_ADDRESS);
	_default_frame.AddUint8(FC_SENSOR_FORMAT);

	for (uint32_t i = 0; i < _num_slaves; i++)
	{
		_default_frame.AddInt8(_slaves[i].getModuleAddress());
		_worker_frame_ptr = _slaves[i].cmdGetFormat();
		_default_frame.AddArray(&NBUS_RX_DATA0(_worker_frame_ptr->GetFrame() + 1), _worker_frame_ptr->GetLength() - (NBUS_RX_META_SIZE + 1)); // add without length byte
	}

	_default_frame.Commit();

	return &_default_frame;
}

DataFrame* NbusBridge::_cmdGetSlaves()
{
	_default_frame.Init();
	_default_frame.AddUint8(NBUS_BROADCAST_ADDRESS);
	_default_frame.AddUint8(NBUS_BRIDGE_ADDRESS);
	_default_frame.AddUint8(FC_SLAVES);

	Nbus_SensorCnt_t sensor_cnt{0, 0};

	for (uint8_t i = 0; i < _num_slaves; i++)
	{
		sensor_cnt = _slaves[i].cmdGetSensorCnt(false);

		_default_frame.AddUint8(_slaves[i].getModuleAddress());
		_default_frame.AddUint8(sensor_cnt.read_only_count);
		_default_frame.AddUint8(sensor_cnt.read_write_count);
    }

	_default_frame.Commit();

	return &_default_frame;
}

void NbusBridge::_cmdSetStop()
{
	_pdu.sa = NBUS_BROADCAST_ADDRESS;
    _communicator->sendToSlave(_makePacket(_pdu, nullptr, 0));
    _run_state = STATE_TO_STOP;
}

void NbusBridge::_cmdSetStart()
{
	_pdu.sa = NBUS_BROADCAST_ADDRESS;
    _communicator->sendToSlave(_makePacket(_pdu, nullptr, 0));
    _run_state = STATE_RUNNING;
}

DataFrame* NbusBridge::_rspSetError(Nbus_EC_e error_code)
{
	_default_frame.Init();
	_default_frame.AddUint8(_pdu.ma);
	_default_frame.AddUint8(_pdu.sa);
	_default_frame.AddUint8(NBUS_SET_ERR_RESPONSE(_pdu.fc));
	_default_frame.AddUint8(error_code);
	_default_frame.Commit();

	return &_default_frame;
}

DataFrame* NbusBridge::_rspSetStatus(Nbus_SC_e status_code)
{
	_default_frame.Init();
	_default_frame.AddUint8(_pdu.ma);
	_default_frame.AddUint8(_pdu.sa);
	_default_frame.AddUint8(_pdu.fc);
	_default_frame.AddUint8(status_code);
	_default_frame.Commit();

	return &_default_frame;
}

DataFrame* NbusBridge::_makePacket(Nbus_PDU_t pdu, uint8_t *data, uint8_t size)
{
	_default_frame.Init();
	_default_frame.AddUint8(pdu.ma);
	_default_frame.AddUint8(pdu.sa);
	_default_frame.AddUint8((Nbus_FC_e)pdu.fc);
	_default_frame.AddArray(data, size);
	_default_frame.Commit();

	return &_default_frame;
}

DataFrame* NbusBridge::_makeBridgeDataPacket()
{

	_bridge_cast_frame.Init();
	_bridge_cast_frame.AddArray(_bridge_cast_header, NBUS_BRIDGE_HEADER_SIZE);		// add header
	_addDataPayload(&_bridge_cast_frame);
	_bridge_cast_frame.AddUint8(_crc8x_fast(_bridge_cast_frame.GetFrame() + NBUS_BRIDGE_HEADER_SIZE, _bridge_cast_frame.GetLength() - NBUS_BRIDGE_HEADER_SIZE)); // add crc8

	return &_bridge_cast_frame;
}


DataFrame* NbusBridge::_forwardPacket(uint8_t *data, uint8_t size)
{
	_raw_data_frame.Init();
	_raw_data_frame.AddUint8(size);
	_raw_data_frame.AddArray(data, size);

	return &_raw_data_frame;
}

void NbusBridge::_addDataPayload(DataFrame * data_frame)
{
	data_frame->AddUint32(_communicator->getTime());

	for (uint32_t i = 0; i < _num_slaves; i++)
	{
		data_frame->AddUint8(_slaves[i].getModuleAddress());
		_worker_frame_ptr = _slaves[i].cmdGetData();

		// check error state
		if (_worker_frame_ptr->GetLength() < (NBUS_RX_META_SIZE + 1) || NBUS_CHECK_ERR_RESPONSE(_worker_frame_ptr->GetFrame() + 1))
		{
			continue;
		}

		data_frame->AddArray(&NBUS_RX_DATA0(_worker_frame_ptr->GetFrame() + 1), _worker_frame_ptr->GetLength() - (NBUS_RX_META_SIZE + 1)); // add without length byte
	}
}