33.1.14.3 PFM Erase

The PFM Erase NVMOP command erases the entire PFM region. 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, setup the PWP register appropriately.

The ability to erase the PFM in the Upper or Lower region allows executing from one panel while erasing (or writing) the other, without the need to complete many Page Erase operations.

The PFM Erase operation is not address based (that is, the FCW directly selects the target Flash panel). The ADDR register is ignored, therefore does not need to be initialized for this NVMOP.

A Panel Erase sequence comprises the following steps:

1. <Desired NVMOP> is Upper or Lower PFM 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.

The Flash memory in a panel mapped to the Upper or Lower PFM region can be erased if write protection is not enabled for addresses associated with that region, 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.