ARM Architecture Reference Manual ARMv7-A and ARMv7-R edition

Recommended External Debug Interface
A.1.7 DBGPWRDUP
DBGPWRDUP is not required in v6 Debug and v6.1 Debug.
DBGPWRDUP is not required in a SinglePower system, that is, it is not required in a design that has only
one power domain.
The DBGPWRDUP input signal is HIGH when the processor is powered up, and LOW otherwise. The
DBGPWRDUP signal is reflected in bit [0] of the Device Power-Down and Reset Status Register.
See also Device Power-down and Reset Status Register (DBGPRSR), v7 Debug only on page C10-34 and
Permissions in relation to power-down on page C6-28.
A.1.8 DBGROMADDR and DBGROMADDRV
DBGROMADDR and DBGROMADDRV are not required in v6 Debug and v6.1 Debug. They are
required in v7 Debug if the memory-mapped interface is implemented.
DBGROMADDR specifies bits [31:12] of the ROM Table table physical address. This is a configuration
input. It must be either:
be a tie-off
change only while the processor is in reset.
In a system with multiple ROM Tables, this address must be tied off to the top-level ROM Table address.
In a system with no ROM Table this address must be tied off with the physical address where the debug
registers are memory-mapped. Debug software can use the debug component identification registers at the
end of the 4KB block addressed by DBGROMADDR to distinguish a ROM table from a processor.
Note
If the system implements more than one debug component, for example a processor and a trace macrocell,
a ROM Table must be provided.
DBGROMADDRV is the valid signal for DBGROMADDR. If the address cannot be determined,
DBGROMADDR must be tied off to zero and DBGROMADDRV tied LOW.
The format of ROM Tables is defined in the ARM Debug Interface v5 Architecture Specification.
A.1.9 DBGSELFADDR and DBGSELFADDRV
DBGSELFADDR and DBGSELFADDRV are not required in v6 Debug and v6.1 Debug.
In v7 Debug, DBGSELFADDR and DBGSELFDDRV are required if the memory-mapped interface is
implemented. If DBGROMADDR and DBGROMADDRV are not implemented, DBGSELFADDR and
DBGSELFADDRV must not be implemented.
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