4.3.5. Lock Register, SYS_LOCK

The SYS_LOCK register at 0x10000020 locks or unlocks access to all lockable registers.

Lockable registers cannot be modified while they are locked. This mechanism prevents the registers from being overwritten accidently. The registers are locked by default after a reset.

Figure 4.6 shows the register bit assignment.

Figure 4.6. SYS_LOCK register

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The function of the register bits are shown in Table 4.9.

Table 4.9. SYS_LOCK register bit assignments

Bits

Access

NameReset

Description

[31:20]

Write ignored, read as zero0x000Undefined
[19:17]Write ignored, read as zerob00Undefined

[16]

Read-only

LOCKEDb1

This bit indicates if the lockable registers are locked or unlocked:

b0 = unlocked

b1 = locked.

[15:0]

Read/Write

LOCKVAL0x0000

Write the value 0xA05F to unlock the lockable registers. Write any other value to this register to lock them.


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