Chapter 21: Realmonitor; Features; Applications; Description - Philips LPC2101 User Manual

RealMonitor is a configurable software module which enables real time debug.
RealMonitor is developed by ARM Inc. Information presented in this chapter is taken from
the ARM document RealMonitor Target Integration Guide (ARM DUI 0142A). It applies to
a specific configuration of RealMonitor software programmed in the on-chip ROM boot
memory of this device.
Refer to the white paper "Real Time Debug for System-on-chip", available at the official
ARM website, for background information.

21.1 Features

21.2 Applications

Real time debugging

21.3 Description

RealMonitor is a lightweight debug monitor that allows interrupts to be serviced while user
debug their foreground application. It communicates with the host using the DCC (Debug
Communications Channel), which is present in the EmbeddedICE logic. RealMonitor
provides advantages over the traditional methods for debugging applications in ARM
systems. The traditional methods include:
Although both of these methods provide robust debugging environments, neither is
suitable as a lightweight real-time monitor.
Angel is designed to load and debug independent applications that can run in a variety of
modes, and communicate with the debug host using a variety of connections (such as a
serial port or ethernet). Angel is required to save and restore full processor context, and
the occurrence of interrupts can be delayed as a result. Angel, as a fully functional
target-based debugger, is therefore too heavyweight to perform as a real-time monitor.
Multi-ICE is a hardware debug solution that operates using the EmbeddedICE unit that is
built into most ARM processors. To perform debug tasks such as accessing memory or
the processor registers, Multi-ICE must place the core into a debug state. While the
processor is in this state, which can be millions of cycles, normal program execution is
suspended, and interrupts cannot be serviced.

User manual

UM10161

Chapter 21: RealMonitor

Rev. 01 — 12 January 2006
•
Allows user to establish a debug session to a currently running system without halting
or resetting the system.
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Allows user time-critical interrupt code to continue executing while other user
application code is being debugged.
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Angel (a target-based debug monitor)
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Multi-ICE or other JTAG unit and EmbeddedICE logic (a hardware-based debug
solution).
Rev. 01 — 12 January 2006
User manual
© Koninklijke Philips Electronics N.V. 2006. All rights reserved.
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