Debugging

General principles

Duaa

Where to start How to narrow down the source of the problem

Power check

• Nothing : open circuit, short circuit, line break, blown fuse, ...
• Voltage too low : power supply impedence, badly selected, ...
• Voltage too high : above max. ratings, dead zener/reg., ...
• GND/VCC loop

Constant => Multimeter. Dynamic/"Random" effect => Oscilloscope.

Multimeter

• Continuity check (+diodes orientation) : symbol
• Voltage check : parallel measurement
• Resistance / current / ...

Be carefull with the cable connexions! (serial VS parallel measurements)

Oscilloscope

[Nicolas & Duaa?]

• "Real" levels
• Dynamic view
• 10MHz - >1GHz ranges
• Few channels (~1-4)
• Trigger/Time/Level
• Expensive (comparatively to logical analyzers)

The poor man's solution : computer's microphone input. (~22KHz)

Logical analyzers

[Henk & Nicolas?]

• Only "logical levels" (0 : <0.6V - 1 : > 1.2V => not CMOS logic!)
• Multiple channels (8-16...)
• "Unexpensive"
• Allows you to read complex protocols (usually computer-based operation)

Serial (or any) "Hello world!"

• Output "Hello world!" messages while your program is executing.
• LED
• Serial
• Other

USB and computer detection

-lsusb

Nicolas & Fran?

TNT for radiofreq?

https://www.gnuradio.org/

Break point and variables observations

Nicolas can do it with PIC + microchip IDE but more than probably better with atmel / arm families => anybody?

Reflow

How to debug almost anything kit

Henk