11.5 Unique ID (UID)
The PIC32CA SG provides a 128 bit (UNIQIDWn, n = 0,1,2,3) which conforms to the version 4 UUID format. See the following table for the location in Flash memory. The unique ID is programmed onto the device at manufacture.
For more information on the standard, refer to the RFC4122 at tools.ietf.org/html/rfc4122.
The version 4 UUID is a 128-bit value which includes 122-bit random value + 2-bit variant code + 4-bit version code. The random value can be generated using the TRNG on the device or with external equipment during test. This form of UID is referred to as a statistically guaranteed unique value because the possibility of a collision is infinitesimally small. It has the advantage that UID values are unique across vendors without the need for a central authority to manage the number space.
| Address Offset Base=CAL OTP | Name | User | Description |
|---|---|---|---|
| Base + 0x01E0 | UNIQIDW0 | User SW | UID[31:0] - Unique ID Word 0 |
| Base + 0x01E4 | UNIQIDW1 | User SW | UID[63:32] - Unique ID Word 1 |
| Base + 0x01E8 | UNIQIDW2 | User SW | UID[95:64] - Unique ID Word 2 |
| Base + 0x01EC | UNIQIDW3 | User SW | UID[127:96] - Unique ID Word 3 |