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TRCPIDR4, Peripheral Identification Register 4

The TRCPIDR4 characteristics are:


Provides discovery information about the component.

For additional information, see the CoreSight Architecture Specification.


This register is present only when FEAT_ETE is implemented. Otherwise, direct accesses to TRCPIDR4 are RES0.


TRCPIDR4 is a 32-bit register.

Field descriptions

The TRCPIDR4 bit assignments are:


Bits [31:8]

Reserved, RES0.

SIZE, bits [7:4]

Size of the component.

The distance from the start of the address space used by this component to the end of the component identification registers.

A value of 0b0000 means one of the following is true:

  • The component uses a single 4KB block.
  • The component uses an IMPLEMENTATION DEFINED number of 4KB blocks.

Any other value means the component occupies 2TRCPIDR4.SIZE 4KB blocks.

Using this field to indicate the size of the component is deprecated. This field might not correctly indicate the size of the component. Arm recommends that software determine the size of the component from the Unique Component Identifier fields, and other IMPLEMENTATION DEFINED registers in the component.

Reads as 0b0000.

DES_2, bits [3:0]

Designer, JEP106 continuation code. This is the JEDEC-assigned JEP106 bank identifier for the designer of the component, minus 1. The code identifies the designer of the component, which might not be not the same as the implementer of the device containing the component. To obtain a number, or to see the assignment of these codes, contact JEDEC

This field reads as an IMPLEMENTATION DEFINED value.


For a component designed by Arm Limited, the JEP106 bank is 5, meaning this field has the value 0x4.

Accessing the TRCPIDR4

External debugger accesses to this register are unaffected by the OS Lock.

TRCPIDR4 can be accessed through the external debug interface:


This interface is accessible as follows:

  • When !IsTraceCorePowered() accesses to this register generate an error response.
  • Otherwise accesses to this register are RO.