A.2 global signals, Table a-1 – ARM Cortex R4F User Manual

Page 416

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Processor Signal Descriptions

ARM DDI 0363E

Copyright © 2009 ARM Limited. All rights reserved.

A-3

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A.2

Global signals

Table A-1 shows the processor global signals.

The free clock is ungated, with minimal insertion delay, because it clocks the clock gating
circuits. Therefore, you must ensure that incoming clocks are balanced with the free clock.

Table A-1 Global signals

Signal

Direction

Clocking

Description

FREECLKIN

Input

-

Free version of the core clock.

CLKIN

Input

-

Core clock.

CLKIN2

Input

-

Core clock, in phase with DUALCKLIN, for configurations
with dual-redundant core.

a

nRESET

Input

Any

Core reset.

nSYSPORESET

Input

Any

System power on reset.

nCPUHALT

Input

Any

Processor halt after reset.

DBGNOCLKSTOP

Input

Any

Processor does not stop the clocks when entering WFI state.

a

DUALCLKIN

Input

-

Clock for second, redundant, core.

a

DUALCLKIN2

Input

-

Clock for second, redundant, core, in phase with CLKIN.

a

STANDBYWFI

Output

FREECLKIN

Indicates that the processor is in Standby mode and the
processor clock is stopped. You can use this signal for TCMs
RAM clock gating.

a. Not available in r0px revisions of the processor.

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