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# CTILSR, CTI Lock Status Register

The CTILSR characteristics are:

## Purpose

Indicates the current status of the Software Lock for CTI registers.

## Configuration

CTILSR is in the Debug power domain. Some or all RW fields of this register have defined reset values. These apply only on an External debug reset. The register is not affected by a Warm reset and is not affected by a Cold reset.

CTILSR is RAZ if the Software Lock is not implemented and is RAZ for other accesses to the external debug interface.

The Software Lock provides a lock to prevent memory-mapped writes to the Cross-Trigger Interface registers. Use of this lock mechanism reduces the risk of accidental damage to the contents of the Cross-Trigger Interface registers. It does not, and cannot, prevent all accidental or malicious damage.

Software uses CTILAR to set or clear the lock, and CTILSR to check the current status of the lock.

## Attributes

CTILSR is a 32-bit register.

## Field descriptions

The CTILSR bit assignments are:

31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0
RES0 | nTT | SLK | SLI

#### Bits [31:3]

Reserved, RES0.

#### nTT, bit [2]

Not thirty-two bit access required. RAZ.

#### SLK, bit [1]

Software Lock status for this component. For an access to LSR that is not a memory-mapped access, or when the Software Lock is not implemented, this field is RES0.

For memory-mapped accesses when the Software Lock is implemented, possible values of this field are:

SLK | Meaning
--- | ---
0b0 | Lock clear. Writes are permitted to this component's registers.
0b1 | Lock set. Writes to this component's registers are ignored, and reads have no side effects.

On a External debug reset, this field resets to 1.

#### SLI, bit [0]

Software Lock implemented. For an access to LSR that is not a memory-mapped access, this field is RAZ. For memory-mapped accesses, the value of this field is IMPLEMENTATION DEFINED. Permitted values are:

SLI | Meaning
--- | ---
0b0 | Software Lock not implemented or not memory-mapped access.
0b1 | Software Lock implemented and memory-mapped access.

## Accessing the CTILSR

#### CTILSR can be accessed through a memory-mapped access to the external debug interface:

Component | Offset | Instance
--- | --- | ---
CTI | 0xFB4 | CTILSR

Access on this interface is RO.

AArch32 Registers | AArch64 Registers | AArch32 Instructions | AArch64 Instructions | Index by Encoding | External Registers | External Registers by Offset | Registers by Functional Group | Proprietary Notice

27/03/2019 21:59; e5e4db499bf9867a4b93324c4dbac985d3da9376

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