7.9 SIGROW - Signature Row

The content of the Signature Row (SIGROW) fuses is pre-programmed and cannot be altered. SIGROW holds information such as device ID, serial number, and calibration values.

All AVR microcontrollers have a three-byte device ID that identifies the device. This device ID can be read using the UPDI interface, also when the device is locked. The three bytes reside in the Signature Row. The signature bytes are given in the following table.