Reverse what I presume is a CRC16 from data samples, so that I can compte the CRC for whatever the data are.

main.dart

/*
Reverse the CRC16 from the data sample.
@Author Stéphane "Sdl" de Luca on Friday June 10th 2022 4:22 in Tangier, Morocco.
@See https://crypto.stackexchange.com/questions/100474/how-can-i-reverse-a-so-called-crc16-from-the-data/100511#100511 for indepth information.
*/

int crc16(int value) {
    const table = [
      //0xBB83, //0000
      0x7A43,   // 0001
      0x3A42,   // 0002
      0xBA40,   // 0004
      0xBA45,   // 0008
      0xBA4F,   // 0010
      0xBA5B,   // 0020
      0xBA73,   // 0040
      0xBA23,   // 0080
      0xBA13,   // 0100
      0xBAE3,   // 0200
      0xB943,   // 0400
      0xBC43,   // 0800
      0xB643,   // 1000
      0xA243,   // 2000
      0x8A43,   // 4000
      0xDA43,   // 8000
    ];

    int crc16 = 0;
    int bitsCount = 0;

    for (int i = 0; i < 16; i++) {
      final mask = 1<<i;
      final bit = value & mask;
      final bool bitIsSet = bit != 0;

      if (!bitIsSet) continue;

  
      if (bitsCount++ == 0) {
        crc16 = table[i];
      } else {
        crc16 ^= table[i];
      }
      
      print("#${i.toString().padLeft(2)}: ${value.toRadixString(16).padLeft(4,'0')} (${value.toRadixString(2).padLeft(16,'-')}))} | mask:${bit.toRadixString(2).padLeft(16,'-')} | crc: ${crc16.toRadixString(16).padLeft(4,'0')}");
    }

    final bool even = bitsCount & 1 == 0;
    print("even: $even");
  
    if (even) crc16 ^= 0xBB83; // for 0000
    return crc16;
  }

/*
For DDDD seconds: d2 06 00 8A DD DD 22 8A
For FFFF seconds: d2 06 00 8A FF FF BA 33
For EEEE seconds: d2 06 00 8A EE EE 76 6F
For FFFE seconds: d2 06 00 8A FF FE 7B F3
For 0000 seconds: d2 06 00 8A 00 00 BB 83
*/


void main() {
  const table = [0x0000, 0xDDDD, 0xEEEE, 0xFFFE, 0xFFFF];
  
    for (int i = 0; i < table.length; i++) {
      final v = table[i];
      
      final crc = crc16(v);
      
      print("crc16[${v.toRadixString(16).padLeft(4, '0')}] => ${crc.toRadixString(16).padLeft(4, '0')}");
          
    }
}
/*
The logs:

even: true
crc16[0000] => bb83
# 0: dddd (1101110111011101))} | mask:---------------1 | crc: 7a43
# 2: dddd (1101110111011101))} | mask:-------------100 | crc: c003
# 3: dddd (1101110111011101))} | mask:------------1000 | crc: 7a46
# 4: dddd (1101110111011101))} | mask:-----------10000 | crc: c009
# 6: dddd (1101110111011101))} | mask:---------1000000 | crc: 7a7a
# 7: dddd (1101110111011101))} | mask:--------10000000 | crc: c059
# 8: dddd (1101110111011101))} | mask:-------100000000 | crc: 7a4a
#10: dddd (1101110111011101))} | mask:-----10000000000 | crc: c309
#11: dddd (1101110111011101))} | mask:----100000000000 | crc: 7f4a
#12: dddd (1101110111011101))} | mask:---1000000000000 | crc: c909
#14: dddd (1101110111011101))} | mask:-100000000000000 | crc: 434a
#15: dddd (1101110111011101))} | mask:1000000000000000 | crc: 9909
even: true
crc16[dddd] => 228a
# 1: eeee (1110111011101110))} | mask:--------------10 | crc: 3a42
# 2: eeee (1110111011101110))} | mask:-------------100 | crc: 8002
# 3: eeee (1110111011101110))} | mask:------------1000 | crc: 3a47
# 5: eeee (1110111011101110))} | mask:----------100000 | crc: 801c
# 6: eeee (1110111011101110))} | mask:---------1000000 | crc: 3a6f
# 7: eeee (1110111011101110))} | mask:--------10000000 | crc: 804c
# 9: eeee (1110111011101110))} | mask:------1000000000 | crc: 3aaf
#10: eeee (1110111011101110))} | mask:-----10000000000 | crc: 83ec
#11: eeee (1110111011101110))} | mask:----100000000000 | crc: 3faf
#13: eeee (1110111011101110))} | mask:--10000000000000 | crc: 9dec
#14: eeee (1110111011101110))} | mask:-100000000000000 | crc: 17af
#15: eeee (1110111011101110))} | mask:1000000000000000 | crc: cdec
even: true
crc16[eeee] => 766f
# 1: fffe (1111111111111110))} | mask:--------------10 | crc: 3a42
# 2: fffe (1111111111111110))} | mask:-------------100 | crc: 8002
# 3: fffe (1111111111111110))} | mask:------------1000 | crc: 3a47
# 4: fffe (1111111111111110))} | mask:-----------10000 | crc: 8008
# 5: fffe (1111111111111110))} | mask:----------100000 | crc: 3a53
# 6: fffe (1111111111111110))} | mask:---------1000000 | crc: 8020
# 7: fffe (1111111111111110))} | mask:--------10000000 | crc: 3a03
# 8: fffe (1111111111111110))} | mask:-------100000000 | crc: 8010
# 9: fffe (1111111111111110))} | mask:------1000000000 | crc: 3af3
#10: fffe (1111111111111110))} | mask:-----10000000000 | crc: 83b0
#11: fffe (1111111111111110))} | mask:----100000000000 | crc: 3ff3
#12: fffe (1111111111111110))} | mask:---1000000000000 | crc: 89b0
#13: fffe (1111111111111110))} | mask:--10000000000000 | crc: 2bf3
#14: fffe (1111111111111110))} | mask:-100000000000000 | crc: a1b0
#15: fffe (1111111111111110))} | mask:1000000000000000 | crc: 7bf3
even: false
crc16[fffe] => 7bf3
# 0: ffff (1111111111111111))} | mask:---------------1 | crc: 7a43
# 1: ffff (1111111111111111))} | mask:--------------10 | crc: 4001
# 2: ffff (1111111111111111))} | mask:-------------100 | crc: fa41
# 3: ffff (1111111111111111))} | mask:------------1000 | crc: 4004
# 4: ffff (1111111111111111))} | mask:-----------10000 | crc: fa4b
# 5: ffff (1111111111111111))} | mask:----------100000 | crc: 4010
# 6: ffff (1111111111111111))} | mask:---------1000000 | crc: fa63
# 7: ffff (1111111111111111))} | mask:--------10000000 | crc: 4040
# 8: ffff (1111111111111111))} | mask:-------100000000 | crc: fa53
# 9: ffff (1111111111111111))} | mask:------1000000000 | crc: 40b0
#10: ffff (1111111111111111))} | mask:-----10000000000 | crc: f9f3
#11: ffff (1111111111111111))} | mask:----100000000000 | crc: 45b0
#12: ffff (1111111111111111))} | mask:---1000000000000 | crc: f3f3
#13: ffff (1111111111111111))} | mask:--10000000000000 | crc: 51b0
#14: ffff (1111111111111111))} | mask:-100000000000000 | crc: dbf3
#15: ffff (1111111111111111))} | mask:1000000000000000 | crc: 01b0
even: true
crc16[ffff] => ba33 
 
*/