5.4 SIGNATURE

Each device has a unique 128-bit serial number, which is a concatenation of four 32-bit words from the Serial Number fuses SERNUM[3:0]. The uniqueness of the serial number is ensured only when all 128 bits are used.

For general device selection purposes, such as by a debugger, the pin/memory configuration of the device is also stored in the Device ID register of the Device Service Unit (DSU).