Turning an oscilloscope into a logic analyzer

Sooner or later, you’re going to need a logic analyzer. If you don’t have a Bus Pirate or Logic Sniffer lying around, [Joonas] has a great MacGyverism that turns an oscilloscope into the simplest logic analyzer ever.

The basic premise of the build is tying four digital lines to the analog input of an oscope. This is done with a 74HC126 buffer that provides a high impedance input for the logic probes and outputs the four-bit status of each logic channel. With a few resistors in an R-2R network, the state of four digital lines can be easily read.

[Joonas] included the source code to turn his Picoscope 2000 into a logic analyzer, but there’s no reason why this couldn’t be done with any digital scope that has a serial output. Not bad for a very, very simple logic analyzer – just one chip and a handful of resistors – that costs less than $5.

5 thoughts on “Turning an oscilloscope into a logic analyzer

  1. Perfect :) I’m carrying this idea in my head for a year. Glad to see that someone had the same idea and moreover – did it! Have to try..

  2. I wonder if this could be used with a Rigol DS1052E, one of the more-popular ‘affordable’ digital oscilloscopes. Seems that it should be doable, given it has USB and serial outputs. But then again, Rigol’s been tightening its belt, so to speak, with each firmware release.

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