Analog Devices ADSP-TS101 TigerSHARC Hardware Reference Manual page 329

9 DEBUG FUNCTIONALITY
The functionality described in this chapter is useful for both software
debugging and services usually found in operating system (OS) kernels.
These features are implemented in the TigerSHARC processor hardware
to allow debuggers and operating systems to build the more complex
aspects of their features. The functionality is grouped into levels. These
levels build upon each other to allow greater control and visibility of the
TigerSHARC processor for the debugger or kernel.
The debugging approach is based on the idea of protected execution (user
mode) and unprotected execution (supervisor mode). In user mode, some
of the system resources can be made accessible. However, when those
resources must be managed by an OS kernel, they are restricted. When
user code tries to access a protected resource, an exception occurs and the
access is aborted.
The debugger can control the TigerSHARC processor in one of two ways:
• using a debug monitor (running in supervisor mode)
• using an In-circuit emulator (ICE)
In supervisor mode, some system resources are allocated to the monitor.
(For example, memory, communication channel-to-host, interrupt, flag
bits, and so on.)
The ICE, on the other hand, uses a reserved communication channel (the
JTAG test access port) to control the TigerSHARC processor. This way
the ICE can be non-intrusive to the system, as well as control systems that
cannot communicate with a host system.
ADSP-TS101 TigerSHARC Processor
Hardware Reference
9-1