6: It Doesn’t Work! CET360 Microprocessor Engineering J. Sumey.
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Transcript of 6: It Doesn’t Work! CET360 Microprocessor Engineering J. Sumey.
6: It Doesn’t Work!
CET360Microprocessor Engineering
J. Sumey
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Stuck in the mud…
“I’ve built and programmed my prototype, but it doesn’t work!”
Now What???
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Wrong Reactions
throw things and curse stomp around awhile and leave haphazardly change wires start taking pot shots at the
software wait for instructor to fix it
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Right Reactions
apply a logical methodology to identifying and correcting the problem
backtrack: when did it last work? what changes were made since then? consult journal!
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Divide and Conquer!
is the problem: hardware? software? or both!?
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Hardware Problems breadboard / wiring errors power supply errors dead batteries shorts faulty components
always be aware! look – smell – touch
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Hardware Troubleshooting
schematic power supply ammeter oscilloscope DSO / logic analyzer LEDs datasheets
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Software Problems
semantic/logic errors data representation errors operator mis-precedence side effects ISR issues I/O register configuration errors
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Software Troubleshooting
breakpoints/single-stepping register/memory display &
manipulation software triggers linker map “heartbeat” debug pulses back-ups!
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Other Tips
SEE (Someone Else’s Eyes) document everything (lab journal) re-read datasheets design reviews