Upgrade suggestions for a Logic Analyzer Tutorial

Other Hardware General Electronics
1

The circuit converts internal Arduino firmware states and events into observable digital signals, allowing a logic analyzer to monitor program execution. This provides non-intrusive, timing-accurate debugging of embedded code.

I use SPI to send 3 bytes (about 4us) i.e. debugging values, to the 24 bit register output.

A 4-channel oscilloscope can also be used with this circuit.

  • The two 74HC595 shift registers generate the signals sent to the logic analyzer.
  • The TPIC6B595 is used to drive diagnostic LEDs.

Hardware changes or improvement are welcomed.

Logic_Analyzer_Interface
Logic_Analyzer_Interface1596×1208 385 KB

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  • The transitionPin can be any pin, 2-9 or A0-A3.
2

:scream:

  • I might short a register output before morning coffee.

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3

Why the TPIC6B595? I'd think the '595s would drive some LEDs without a problem.

4

  • A 595 output is limited in its sinking capacity ~5mA, package is 70mA.
    This would be sufficient for today’s LEDs. :thinking:

  • I thought the TPIC6B595 might be a good option in case I needed more capability.

    • Maybe turning my electric heater on. :roll_eyes:

  • The TPIC can withstand up to 50v which might have some advantage.

5

Plenty for a modern LED used as an indicator.

6
  • Three 595s was my first thought too.
  • Had, on a few occasions, thought an active buzzer to get my attention might be nice.
7
  • For use with a 3v power supply, maybe three 74HC595s would be best.
    An ULN2803 could be added to the last register if current drive was needed. :thinking:

Here is one last option.

  • Since some logic analyzers are 5V only, adding the optional 74AHC125 will allow them to operation with either microcontroller, i.e. 3v or 5v.
    I'll stick with this circuit:

Logic Analyzer Interface
Logic Analyzer Interface1920×1444 394 KB