| .. |
| Copyright 2020 NXP |
| |
| |
| .. highlight::shell |
| |
| .. _se05x-time-stamp: |
| |
| ================================================= |
| SE05X Timestamp |
| ================================================= |
| |
| The timestamp is a 12-byte value. The most significant |
| 4 bytes are persistent and the least significant 8 |
| bytes are transient. The persistent value is |
| incremented at every session open and the transient |
| 8 bytes are incremented every 100ms and reset at |
| every session open. |
| |
| So every time the timestamp is read, the newer value |
| will always be greater than the previous value. |
| |
| This example demonstrates that the timestamp value |
| is incremented internally. Timestamp is used by the |
| applet during attestation. We initially read the |
| timestamp value and then perform attestation |
| operation. We compare the initial timestamp with |
| the timestamp received during attestation. The newer |
| value must be greater than the older value. |
| |
| |
| Building |
| ================================================= |
| |
| Build the project with the following configuration. |
| |
| - ``Applet=SE05X_C`` |
| - ``Project = se05x_TimeStamp`` |
| |
| Running |
| ================================================= |
| |
| On successful execution, you would be able to see |
| the timestamp printed out:: |
| |
| App :INFO :timestamp.ts (Len=12) |
| 00 00 00 08 00 00 00 00 00 1F BD 00 |
| App :INFO :new_timestamp.ts (Len=12) |
| 00 00 00 08 00 00 00 00 00 20 B7 00 |
| App :INFO :ex_sss Finished |
| |
| As you can see in the above logs, the timestamp value |
| received during attestation operation is larger than |
| the previous value. |
