AN2848 Freescale Semiconductor / Motorola, AN2848 Datasheet - Page 12

• Manufacturer Part Number: AN2848
• Description: Programming the eTPU
• Manufacturer: Freescale Semiconductor / Motorola

Simulating the eTPU Function
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When a function under development is simulated on the Ash Ware stand-alone simulator, the simulator
script files take the place of the host CPU. The simulator is a powerful development tool which is seldom
used to its fullest capacity. However, after an hour or two in the training class, most users become
sufficiently proficient to analyze and debug common designs. Here are some of the more useful features
of the stand-alone simulator:
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The eTPU is a very powerful device, more complicated and with many more dimensions than a CPU. The
unique channel design allows the processing engine to meet the drive requirements of practically any
physical control system. However, with the power comes a complexity that can be daunting to the new
user. This note was intended to suggest some steps for a successful design approach, and to point out
possible traps and pitfalls in eTPU systems design. The advice is drawn from experience with real systems.
In addition to the design hints, it suggests sources for further information.
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Issue an initialization Host Service Request (HSR) to the channel. Note that a service request is
necessary for an eTPU function thread to execute. No eTPU operation can occur until at least one
HSR is issued. However, depending on the eTPU software, once a channel is started, the eTPU
software can schedule new service threads without additional HSRs from the host. Also, it is
possible for a software thread on one channel to cause a service request on another channel.
Interact with the eTPU threads according to the system design. This can involve simple reading or
writing parameters, or coordinated interrupt handling and service requests.
Setting up one or more channels using commands similar to your host code. This includes
interconnecting channels of the eTPU to test more complex systems.
Providing external input pin stimuli through a script file. The pin transition can be timed to
simulate a number of external inputs, and can be interleaved with “host” operations in the script
file.
Displaying output pin action against time in a logic analyzer window. Hint: if you are having
trouble finding your output signal, try checking the “Auto Scroll” button.
Reading and modifying memory and watching source symbolic values.
Breakpointing the script or the code of any function.
Reading or modifying the contents of internal registers.
Stepping through the code by instruction, source line, or thread.
Tracing through recent history cycle by cycle.
Post processing performance analysis.
Automated testing.
Simulating the eTPU Function
Summary
Programming the eTPU, Rev. 0
Freescale Semiconductor