TRCPRGCTLR, Programming Control Register
The TRCPRGCTLR characteristics are:
Enables the trace unit.
External register TRCPRGCTLR bits [31:0] are architecturally mapped to AArch64 System register TRCPRGCTLR[31:0] .
This register is present only when ETE is implemented. Otherwise, direct accesses to TRCPRGCTLR are RES0.
TRCPRGCTLR is a 32-bit register.
The TRCPRGCTLR bit assignments are:
EN, bit 
Trace unit enable.
The trace unit is disabled.
The trace unit is enabled.
On a Trace unit reset, this field resets to 0.
Accessing the TRCPRGCTLR
Must be programmed.
TRCPRGCTLR can be accessed through the external debug interface:
This interface is accessible as follows:
- When OSLockStatus(), or !AllowExternalTraceAccess() or !IsTraceCorePowered() accesses to this register generate an error response.
- Otherwise accesses to this register are RW.