Datasheet

• BUFFERED: WP command triggered only in case of NVM page crossing. This mode increases the
NVM wear-leveling but is more sensitive to power loss. SEESTAT.LOAD is high when the pagebuffer
contains unwritten data.
When SEECFG.WMODE selects the buffered mode, the page buffer can contain unwritten
SmartEEPROM data. This is reflected by SEESTAT.LOAD. To flush the SmartEEPROM data inside the
page buffer, issue the SEEFLUSH command.
INTFLAG.SEEWRC indicates when a AHB write to the SmartEEPROM has completed:
1. Unbuffered mode: AHB write has completed, NVM is programmed with correct values except if
INTFLAG.SEESOVF was thrown.
2. Buffered mode: AHB write has completed,
– if SEESTAT.LOAD = 0: NVM is programmed with correct values, except if INTFLAG.SEESOVF
was thrown.
– otherwise; new data is in the page buffer, but is not yet programmed in the NVM.
25.6.8.7 SmartEEPROM Sector Reallocation
The SEES reallocation is performed by default in hardware when the the next available page in the
master index reaches the maximum SEEP number. Automatic reallocation can be disabled by writing a
one in SEECFG.APRDIS. The sector reallocation can also be trigged manually by issuing the
SEERALOC command. The SEES reallocation process consists of:
• Erase the non active sector.
• Copying the active sector valid data to the other sector, old data is filtered.
• Swap ASEES either by issuing the ASEES1 command if SEESTAT.ASEES is reading ‘0’ or by
issuing the ASEES0 command if SEESTAT.ASEES is read as ‘1’.
This process is by default automatically handled by hardware, and indicated by the SEESTAT.BUSY flag.
If in buffered mode, the page buffer must be flushed before triggering a reallocation; otherwise, the
content of the pagebuffer would be lost.
Note: The BKSWRST command triggers automatically the reallocation algorithm which operates as
described above except copy is done in the same active sector but in the first bank. This operation is
atomic, meaning that no modify operation can be issued in the mean time.
As the total size of the whole SEEP exceeds the SmartEEPROM virtual size for a given configuration
there is always free SEEP to replace existing data. In the case all addresses have been written, after
sector reallocation the number of free SEEP is given in the following table.
Table 25-9. Minimum number of free SEEP after sector reallocation
SEESTAT
.PSZ:
SEESTAT
.SBLK
4 8 16 32 64 128 256 512
0 N/A N/A N/A N/A N/A N/A N/A N/A
1 16 16 16 16 31 15 7 3
2 16 16 16 16 16 47 23 11
3 16 16 16 16 16 16 23 11
4 16 16 16 16 16 16 55 27
SAM D5x/E5x Family Data Sheet
NVMCTRL – Nonvolatile Memory Controller
© 2019 Microchip Technology Inc.
Datasheet
DS60001507E-page 656