27.5.6.5 Page Buffer
The page buffer is automatically cleared to all-ones after any page write operation (WP or WQW command). If a partial page has been written and it is desired to clear the contents of the page buffer, the Page Buffer Clear (PBC) command can be used. The status of the page buffer is given by STATUS.LOAD. This bit indicates that the NVM page buffer has been loaded with one or more words. Immediately after an NVM load has been performed, this flag is set, and it remains set until a WP or WQW or a PBC command is given.
The Page Buffer cannot be written while a write command is executing in the NVM. Trying to do so stalls the AHB bus. To avoid stalling the AHB bus, STATUS.READY can by polled prior to issue a write command.
Clearing the page buffer also clears to all ones the PBLDATA0 and PBLDATA1.