Arduino sending data with checksum CRC16

Projects Programming
25

The crcData I show with the serial.print in the master code does not show up on the serial monitor for some reason.

That is because you are trying to print arbitrary binary data bytes as printable characters. They are often not printable.

Modify lines like this:
Serial.println(buffer[crcIndex]);
To this:
Serial.println(buffer[crcIndex], HEX);

and report the two sets of CRC values in hexadecimal notation.

As an aside, there is absolutely no reason to use Strings, as follows. They just lead to confusion. Use zero-terminated character arrays instead (C-strings).

void command(String value) {
  memset(serialBuffer, 0, sizeof serialBuffer);
  sendToUART(serialBuffer, value);
}