SAM3N0C Atmel Corporation, SAM3N0C Datasheet - Page 28

• Manufacturer Part Number: SAM3N0C
• Manufacturer: Atmel Corporation

7.2.3.4
7.2.3.5
7.2.3.6
7.2.3.7
7.2.3.8
28
SAM3N
Flash Speed
Lock Regions
Security Bit Feature
Calibration Bits
Unique Identifier
The user needs to set the number of wait states depending on the frequency used.
For more details, refer to the AC Characteristics sub section in the “Electrical Characteristics”
section.
Several lock bits used to protect write and erase operations on lock regions. A lock region is
composed of several consecutive pages, and each lock region has its associated lock bit.
Table 7-1.
If a locked-region’s erase or program command occurs, the command is aborted and the EEFC
triggers an interrupt.
The lock bits are software programmable through the EEFC User Interface. The command “Set
Lock Bit” enables the protection. The command “Clear Lock Bit” unlocks the lock region.
Asserting the ERASE pin clears the lock bits, thus unlocking the entire Flash.
The SAM3N features a security bit, based on a specific General Purpose NVM bit (GPNVM bit
0). When the security is enabled, any access to the Flash, either through the ICE interface or
through the Fast Flash Programming Interface, is forbidden. This ensures the confidentiality of
the code programmed in the Flash.
This security bit can only be enabled, through the command “Set General Purpose NVM Bit 0” of
the EEFC User Interface. Disabling the security bit can only be achieved by asserting the
ERASE pin at 1, after a full Flash erase is performed. When the security bit is deactivated, all
accesses to the Flash are permitted.
It is important to note that the assertion of the ERASE pin should always be longer than 200 ms.
As the ERASE pin integrates a permanent pull-down, it can be left unconnected during normal
operation. However, it is safer to connect it directly to GND for the final application.
NVM bits are used to calibrate the brownout detector and the voltage regulator. These bits are
factory configured and cannot be changed by the user. The ERASE pin has no effect on the cal-
ibration bits.
Each device integrates its own 128-bit unique identifier. These bits are factory configured and
cannot be changed by the user. The ERASE pin has no effect on the unique identifier.
SAM3N4
SAM3N2
SAM3N1
Product
Lock bit number
Number of lock bits
16
8
4
16 kbytes (64 pages)
16 kbytes (64 pages)
16 kbytes (64 pages)
Lock region size
11011A–ATARM–04-Oct-10