User`s guide

84 CPU32 Emulation
Chapter 5: Connecting and Configuring the Emulator
Configuring the Emulator
rate specified in the configuration can support.
Resetting the target processor also resets the SYNCR to its default
value. If the target processor is reset while running user code (as
opposed to putting the processor in a reset state from the interface),
no communications rate change takes place within the emulator. The
initialization code that runs on the target system from reset is required
to set the SYNCR to the correct value.
When the target processor clock rate is fixed through the use of an
external clock source, the Processor Clock Rate parameter can be set
to the highest rate that is equal to or less than the target clock rate.
There are no dependencies upon any other configuration parameters.
When the target system is using the internal clock synthesizer to
increase the final clock rate but the user leaves the emulator at the
default processor type (683xx) the EMSYNCR is not available to the
configuration process. The powerup default clock rate for the target
system can be entered into the "Processor Clock Rate". This is a
failsafe setting but can limit the emulator performance if the target
processor is programmed to run at a significantly faster rate than the
powerup default.
If the user desires the higher performance available by setting the
"Processor Clock Rate" configuration parameter to his final value but
does not set his processor type (which means that the configuration
process cannot set the SYNCR) the debugger interface will have a
number of failures when invoked because it cannot communicate
accurately with the target processor. These will show up as either
dashes or bad values in the source, backtrace, and memory windows.
These errors can be cleared up if the target system can support a "run
from reset" with code in the target system that initializes the target
SYNCR register. Following the target initializing this register, a break
can be requested and the emulator will communicate correctly with the
target. Until the emulator and the target system are running at
compatible rates, operations such as "run," "load," "modify memory/
registers," or "display memory/registers" will either fail or give incorrect
information.
If the user loses communication between the emulator and the target
system because of incompatible clock rates, control of the target