Each HDC302x is configured with a unique 48-bit value that is used to support NIST traceability of the temperature and relative humidity sensor. It can also be used to represent the unique serial number for that device. Three commands are required to read the full 48-bit value as illustrated in Figure 8-37, Figure 8-38, and Figure 8-39. Each command will return two bytes of NIST ID followed by a CRC byte. From MSB to LSB, the full device NIST ID is read as NIST_ID_5, NIST_ID_4, NIST_ID_3, NIST_ID_2, NIST_ID_1, and NIST_ID_0.