我在这里碰到了一堵砖墙，我需要你的帮助。我有一台财政打印机（Datecs DP-50）可以集成到进行销售的chrome扩展程序应用程序上。问题是我们不能使用驱动程序，因为该应用程序将在远程服务器上运行，而不是在运营商设备上运行，我们必须发送原始数据。该应用程序使用Laravel 5.1作为额外信息在PHP中编码。
所以我有一个带有自定义多项式 x^15+1 的 CRC 基数 16，但它比这多一点，我无法弄清楚。我将在下面粘贴手册中的文档。
The two CRC bytes are calculated according to the formula x^15 + 1. In the
calculation are included all data bytes plus the byte for block end. Every byte passes
through the calculation register from teh MSB to LSB.
Three working bytes are used - S1, S0 and TR
S1 - Most significant byte from the CRC ( it is transmitted immediatelly after END)
S0 - Least significant byte from the CRC ( It is transmitted after S1)
TR - the current transmitted byte in the block.
The CRC is calculated as follows:
1. S1 and S0 are zeroed
2. TR is loaded with the current transmitted byte. The byte is transmitted.
3. Points 3.1 and 3.2 are executed 8 times:
3.1. S1, S0 and TR are shifted one bit to the left.
3.2. If the carry bit from S1 is 1, the MSB of S1 and LSB of S0 are inverted.
Points 2 and 3 are executed for all bytes, included in the calculation of the CRC - from
the first byte after BEG up to and including byte END.
4. TR is loaded with 0 and point 3 is executed
5. TR is loaded with 0 and point 3 is executed
6. Byte S1 is transmitted
7. Byte S0 is transmitted
例如，"A"字符串的CRC（仅S1和S0）是十六进制：fe 09。对于"B"=>fc 09，对于"C"=>7d f6。完整的CRC将是"A"的0d fe 09。串行COM监视器中的TR似乎是一个常量，并且始终表示为0d十六进制。
任何帮助解码这一点将不胜感激。提前感谢！
除了拼写错误之外，该描述还有缺陷，因为它忽略了S1，S0，TR寄存器在左移时应被视为单个24位寄存器的关键细节。如果你这样做，那么你就会得到你引用的结果。您需要在计算中包含0x0d（"END"字节）。
function crc16($crc, $byte) {
$crc = ($crc << 8) + $byte;
for ($k = 0; $k < 8; $k++)
$crc = ($crc & 0x800000) == 0 ? $crc << 1 : ($crc << 1) ^ 0x800100;
$crc = ($crc >> 8) & 0xffff;
return $crc;
}
$crc = 0;
$crc = crc16($crc, ord("A"));
$crc = crc16($crc, 13);
$crc = crc16($crc, 0);
$crc = crc16($crc, 0);
echo dechex($crc);
给fe09.