ARM ARM DUI 0224I Lock Register, Syslock, Describes the PB926EJ-S Lock Register bit assignment

Programmer’s Reference

4.3.5Lock Register, SYS_LOCK

The SYS_LOCK register at 0x10000020 locks or unlocks access to the following registers:

•Oscillator registers, SYS_OSCx

•Reset values for oscillators, SYS_OSCRESETx

•Configuration registers, SYS_CFGDATAx

•Reset control register, SYS_RESETCTL

The control 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 4-9 shows the bit assignment of the register.

Figure 4-9 Lock Register, SYS_LOCK

Table 4-7 describes the PB926EJ-S Lock Register bit assignment.

Table 4-7 Lock Register, SYS_LOCK bit assignment

Bits	Access	Description
[31:17] Reserved. Use read-modify-write to preserve value.
[16]	Read	LOCKED, this bit indicates if the control
		registers are locked or unlocked:
		0	= unlocked
		1	= locked.
[15:0]	Read/write	LOCKVAL, write the value 0xA05F to unlock
		the control registers. Write any other value to
		this register to lock the registers.

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