TX Arbitrator functional coverage
Add functional coverage to TX arbitrator for following things:
- Locking the Data by CAN Core.
- Each buffer selected for transmission and Locking from each Buffer.
- Unlocking the data.
- Change of selected TXT Buffer to another buffer, while both buffers are Ready (priority change).
- Change of selected TXT Buffer to another buffer, first buffer became non-Ready.
- Two buffers with equal priority ready.
- All buffers Ready.
- Assertion on: Never have LOCK when Buffer is not ready!
- Assertion on: Change of selected Buffer. Buffer available should go low for three cycles and then high again.
- Selected buffer changed (between transmissions, txtb_changed).
- Buffer selected, Load started, but Timestamp is not reached (Waiting for transmission at given time).