Datasheet

279
11011B–ATARM–21-Feb-12
SAM3N
18.3.3 Flash Commands
The Enhanced Embedded Flash Controller (EEFC) offers a set of commands such as program-
ming the memory Flash, locking and unlocking lock regions, consecutive programming and
locking and full Flash erasing, etc.
Commands and read operations can be performed in parallel only on different memory planes.
Code can be fetched from one memory plane while a write or an erase operation is performed
on another.
In order to perform one of these commands, the Flash Command Register (EEFC_FCR) has to
be written with the correct command using the FCMD field. As soon as the EEFC_FCR register
is written, the FRDY flag and the FVALUE field in the EEFC_FRR register are automatically
cleared. Once the current command is achieved, then the FRDY flag is automatically set. If an
interrupt has been enabled by setting the FRDY bit in EEFC_FMR, the corresponding interrupt
line of the NVIC is activated. (Note that this is true for all commands except for the STUI Com-
mand. The FRDY flag is not set when the STUI command is achieved.)
All the commands are protected by the same keyword, which has to be written in the 8 highest
bits of the EEFC_FCR register.
Writing EEFC_FCR with data that does not contain the correct key and/or with an invalid com-
mand has no effect on the whole memory plane, but the FCMDE flag is set in the EEFC_FSR
register. This flag is automatically cleared by a read access to the EEFC_FSR register.
When the current command writes or erases a page in a locked region, the command has no
effect on the whole memory plane, but the FLOCKE flag is set in the EEFC_FSR register. This
flag is automatically cleared by a read access to the EEFC_FSR register.
Table 18-2. Set of Commands
Command Value Mnemonic
Get Flash Descriptor 0x00 GETD
Write page 0x01 WP
Write page and lock 0x02 WPL
Erase page and write page 0x03 EWP
Erase page and write page then lock 0x04 EWPL
Erase all 0x05 EA
Set Lock Bit 0x08 SLB
Clear Lock Bit 0x09 CLB
Get Lock Bit 0x0A GLB
Set GPNVM Bit 0x0B SGPB
Clear GPNVM Bit 0x0C CGPB
Get GPNVM Bit 0x0D GGPB
Start Read Unique Identifier 0x0E STUI
Stop Read Unique Identifier 0x0F SPUI
Get CALIB Bit 0x10 GCALB