ARM r1p3, R4, R4F

Debug

ID013010 Non-Confidential, Unrestricted Access

DBGSELFADDR

The DBGSELFADDR signal specifies bits [31:12] of the offset from the debug ROM physical

address to the physical address where the processor APB port is mapped to the base of the 4KB

debug register map. This is a configuration input and must be tied off or only change while the

processor is in reset.

DBGSELFADDRV is the valid signal for DBGSELFADDR. If the offset cannot be

determined, DBGSELFADDR must be tied off to zero and DBGSELFADDRV must be tied

LOW. The value of these signals can be read from the Debug Self Address Register (DSAR).

DBGRESTART

The DBGRESTART signal is used to bring the processor out of debug halt state. The processor

acknowledges DBGRESTART by asserting DBGRESTARTED, and then starts fetching

instructions when DBGRESTART is deasserted.

DBGRESTARTED

The processor asserts DBGRESTARTED in response to a DBGRESTART request, when it is

ready to exit debug halt state and return to normal run state.

DBGTRIGGER

The processor asserts DBGTRIGGER to indicate that the system has accepted a debug request

and attempts to enter debug state. It is not a handshake for the EDBGRQ signal. If DBGACK

does not go HIGH following DBGTRIGGER, the memory system has stopped responding and

the processor has not entered debug state.

TableA-13 on page A-17 shows the debug miscellaneous signals.

11.10.3 Authentication signals

Table11-42 shows a list of the valid authentication signals and the associated debug

permissions. Authentication signals are used to configure the processor so its activity can only

be debugged or traced in a certain subset of processor modes.

Changing the authentication signals

The NIDEN, and DBGEN input signals are either tied off to some fixed value or controlled by

some external device.

Table11-42 Authentication signal restrictions

DBGENa

a. When DBGEN is LOW, the processor behaves as if

DSCR[15:14] equals b00 with the exception that halting

debug events are ignored when this signal is LOW.

NIDEN Non-invasive debug permitted

in User and Privileged modes

00No

X1Yes

10Yes