SAM7X128_14 Datasheet, PDF (126/662 Pages) ATMEL Corporation – ARM-based Flash MCU

In the same way, the Clear Lock command (CLB) is used to clear lock bits. All the lock bits can also be cleared by the
EA command.
Table 20-23. Set and Clear Lock Bit Command
Read/Write
DR Data
Write
SLB or CLB
Write
Bit Mask
Lock bits can be read using Get Lock Bit command (GLB). When a bit set in the Bit Mask is returned, then the
corresponding lock bit is active.
Table 20-24. Get Lock Bit Command
Read/Write
DR Data
Write
GLB
Read
Bit Mask
20.3.4.5 Flash General-purpose NVM Commands
General-purpose NVM bits (GP NVM) can be set with the Set GPNVM command (SGPB). Using this command, several
GP NVM bits can be activated at the same time. Bit 0 of Bit Mask corresponds to the first GPNVM bit and so on.
In the same way, the Clear GPNVM command (CGPB) is used to clear GP NVM bits. All the general-purpose NVM bits
are also cleared by the EA command.
Table 20-25. Set and Clear General-purpose NVM Bit Command
Read/Write
DR Data
Write
SGPB or CGPB
Write
Bit Mask
GP NVM bits can be read using Get GPNVM Bit command (GGPB). When a bit set in the Bit Mask is returned, then the
corresponding GPNVM bit is set.
Table 20-26. Get General-purpose NVM Bit Command
Read/Write
DR Data
Write
GGPB
Read
Bit Mask
20.3.4.6 Flash Security Bit Command
Security bits can be set using Set Security Bit command (SSE). Once the security bit is active, the Fast Flash
programming is disabled. No other command can be run. Only an event on the Erase pin can erase the security bit once
the contents of the Flash have been erased.
The AT91SAM7X512 security bit is controlled by the EFC0. To use the Set Security Bit command, the EFC0 must be
selected using the Select EFC command.
Table 20-27. Set Security Bit Command
Read/Write
DR Data
Write
SSE
Once the security bit is set, it is not possible to access FFPI. The only way to erase the security bit is to erase the Flash.
In order to erase the Flash, the user must perform the following:
 Power-off the chip
 Power-on the chip with TST = 0
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
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