31.2.16.3 PFM Dual Panel Erase

All the PFM (both panels) may be erased using the Program Erase NVMOP command. This mode leaves all BFM and CFM pages intact and is intended to be used by a field upgradeable device. To guard against accidental erasure user code should setup PWPx appropriately.

The PFM Erase operation is not address based (i.e. the FCW directly selects the target flash panel). The ADDR register is ignored so does not need to be initialized for this NVMOP.

A Program Erase sequence comprises the following steps:

  1. <Desired NVMOP> is Program Erase.
  2. Follow the Start Sequencer from Start Sequencer.
  3. Wait for NVM Interrupt from Interrupts.
  4. Check the INTFLAG bits to ensure that the program sequence completed successfully, and then clear all bits in INTFLAG. See Errors and Flags about error flags.
  5. Unlock the hardware write mutex by setting the LOCK bit to ‘0’ and the OWNER field to ‘00’ simultaneously to the MUTEX register.

All PFM can be erased if all associated page write protection is not enabled, see Debug Access Level.

If in mission mode, the application must NOT be executing from the erased region. If any initiator reads from the panel containing the region being erased, all Flash accesses are stalled until the erase completes.

Program Erase Timing

Program Erase timing is dominated by setup (Tnvs), erase time (Terase) and recovery (Trcv) delays.

Program Erase = 2 * (Tnvs + Terase + Trcv + Trw)

Note: For write timing, see the Non-Volatile Memory Controller (NVM) Electrical Specifications section in the Electrical Specifications chapter.