bat-remote/main/src/nbus/nbus_broadcast_comm.cpp

#include "nbus_broadcast_comm.h"

uint8_t const NbusBroadcastComm::_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};

uint8_t NbusBroadcastComm::_crc8x_fast(void const *mem, uint16_t len)
{
    uint8_t crc = CRC8_INIT_VALUE;
    uint8_t const *data = (uint8_t *)mem;
    if (data == NULL)
        return 0xff;
    crc &= 0xff;
    while (len--)
        crc = _crc8x_table[crc ^ *data++];
    return crc;
}

NbusBroadcastComm::NbusBroadcastComm(Stream &slave_interface) :_slave_interface{slave_interface}
{

}

void NbusBroadcastComm::cmd_set_start()
{
   _init_packet(CMD_SET_START, nullptr, 0);
   _slave_interface.write(_packet, _size);
}

void NbusBroadcastComm::cmd_set_stop()
{
    _init_packet(CMD_SET_STOP, nullptr, 0);
    _slave_interface.write(_packet, _size);
}

void NbusBroadcastComm::cmd_set_data(uint8_t *data, int16_t count)
{
    _init_packet(CMD_SET_DATA, data, count);
    _slave_interface.write(_packet, _size);
}

void  NbusBroadcastComm::_init_packet(uint8_t fc, uint8_t *data, int16_t count)
{   
    if (count > NBUS_COMM_PACKET_SIZE - NBUS_META)
        return;

    _size = 0;
    _packet[_size++] = NBUS_PACKET_META + count;
    _packet[_size++]  = 0;
    _packet[_size++]  = 0;
    _packet[_size++]  = fc;
    _add_data(data, count);
    _add_crc();
}

void NbusBroadcastComm::_add_data(uint8_t *data, int16_t count)
{
    if (data == nullptr || count == 0)
        return;

    for (int16_t i = 0; i < count; i++)
        _packet[_size++] = data[i];
}

void NbusBroadcastComm::_add_crc()
{
    _packet[_size] = _crc8x_fast(_packet + 1, _size - 1);
    _size++;
}