System information

18
Custom Tool Examples,
Microprocessor Code
Reconstruction
The original trace (below) came
from the bus of a MPC 555 proces-
sor. As you can see, no data was
placed on the bus at the time of
the trace. This is because cache
memory was turned on. Normally,
it would not be possible to inverse
assemble this trace.
The output of the custom tool in
this example is shown below.
Notice that there is now data in
the DATA column. The custom
tool was able to reconstruct the
code flow after the trace was
taken. This is because the
MPC 555 processor supports
branch trace messages.
The Tool Development Kit
(continued)
Original Trace
Output of Custom Tool
Parameter Window of Custom Tool
The code was reconstructed by
using the branch trace messages
and information in the SRecord
file created when the code was
compiled. The tool took the
address of the appropriate states
in the trace data and found the
corresponding code (data) in the
SRecord file. This created a trace
that the MPC 555 inverse assem-
bler could operate on properly.
By entering information here, users can direct
the tool to the correct SRecord file and control
how much of the data the tool is to operate on.
They can also indicate if the AT2 pin of the
MPC 555 processor is in use.