EDDEVID1, External Debug Device ID Register 1

The EDDEVID1 characteristics are:

Purpose

Provides extra information for external debuggers about features of the debug implementation.

Configuration

When FEAT_DoPD is implemented, EDDEVID1 is in the Core power domain. Otherwise, EDDEVID1 is in the Debug power domain.

Attributes

EDDEVID1 is a 32-bit register.

Field descriptions

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																								HSR				PCSROffset

Bits [31:8]

Reserved, RES0.

HSR, bits [7:4]

Indicates support for the External Debug Halt Status Register, EDHSR. Defined values are:

HSR	Meaning
0b0000	EDHSR not implemented, and the PE follows behaviors consistent with all of the EDHSR fields having a zero value.
0b0001	EDHSR implemented.
0b0010	As 0b0001, but extends EDHSR to include the VNCR, CM, and WnR fields.

All other values are reserved.

FEAT_EDHSR implements the functionality identified by the value 0b0001.

FEAT_Debugv8p9 implements the functionality identified by the value 0b0010.

When FEAT_Debugv8p2 is not implemented, the only permitted value is 0b0000.

From Armv8.9, the values 0b0000 and 0b0001 are not permitted.

PCSROffset, bits [3:0]

Indicates the offset applied to PC samples returned by reads of EDPCSR. Permitted values of this field in Armv8 are:

PCSROffset	Meaning
0b0000	EDPCSR not implemented.
0b0010	EDPCSR implemented, and samples have no offset applied and do not sample the instruction set state in AArch32 state.

When FEAT_PCSRv8p2 is implemented, the only permitted value is 0b0000.

Note

FEAT_PCSRv8p2 implements the PC Sample-based Profiling Extension in the Performance Monitors register space, as indicated by the value of PMU.PMDEVID.PCSample.

Accessing EDDEVID1

EDDEVID1 can be accessed through the external debug interface:

Component	Offset	Instance
Debug	0xFC4	EDDEVID1

This interface is accessible as follows:

When FEAT_DoPD is not implemented or IsCorePowered(), accesses to this register are RO.
Otherwise, accesses to this register generate an error response.

04/07/2023 11:22; 1b994cb0b8c6d1ae5a9a15edbc8bd6ce3b5c7d68