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TRCCCCTLR, Trace Cycle Count Control Register

The TRCCCCTLR characteristics are:

Purpose

Set the threshold value for cycle counting.

Configuration

External register TRCCCCTLR bits [31:0] are architecturally mapped to AArch64 System register TRCCCCTLR[31:0].

This register is present only when FEAT_ETE is implemented, FEAT_TRC_EXT is implemented, and TRCIDR0.TRCCCI == '1'. Otherwise, direct accesses to TRCCCCTLR are RES0.

Attributes

TRCCCCTLR is a 32-bit register.

Field descriptions

Bits [31:12]

THRESHOLD, bits [11:0]

Accessing TRCCCCTLR

Must be programmed if TRCCONFIGR.CCI == 1.

Writes are CONSTRAINED UNPREDICTABLE if the trace unit is not in the Idle state.

TRCCCCTLR can be accessed through the external debug interface:

Accessible as follows:

• When OSLockStatus(), or !AllowExternalTraceAccess(addrdesc), or !IsTraceCorePowered(), accesses to this register generate an error response.
• Otherwise, accesses to this register are RW.

2026-03-26 20:27:25, 2026-03_rel

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