28.2.71 __builtin_write_NVM_secure

Description

Enables the Flash for writing by issuing an unlock sequence specified by two keys and enabling the Write bit of the NVMCON register. After completion, the two keys are cleared to zero.

Interrupts may need to be disabled for proper operation.

This builtin function can be used as a part of a complex sequence discussed in your device data sheet or Family Reference Manual (FRM). See these documents for more information.

Prototype

void __builtin_write_NVM_secure(unsigned int key1, unsigned int key2);

Argument

key1 – first key in the NVM unlock sequence

key2 – second key in the NVM unlock sequence

Return Value

None

Assembler Operator/ Machine Instruction

Depending on the location of the keys:

mov   W0, Wn
mov   Wn, _NVMKEY
mov   W1, Wn
mov   Wn, _NVMKEY
bset  _NVMCON, #15
nop
nop

Error Messages

None