Logic analyzer add-on for the MSP430 Launchpad

Here’s a 6-channel logic analyzer shield for the MSP430 Launchpad. It manages an eyebrow-raising 16 million samples per second. The prototype seen above is made on a hunk of protoboard with point-to-point soldering. [oPossum] did lay out a PCB — which is just 50mmx50mm — but has not had any produced quite yet.

He calls it the LogicBoost, and based it on the the LogicShrimp design. The sextuplet of 8-pin chips are all SPI RAM. These are responsible for storing the samples, with a 74HC573 latch routing the traffic. The MSP430 chip provides the SPI clock, and the Launchpad’s virtual com port can be used to push the data to a computer for graphing. That’s a bit slow so [oPossum] also included an optional header for an FTDI board that will do a faster job. The sample rate can be adjusted by tweaking the internal oscillator setting of the chip; there’s plenty to choose from so it will work for just about any purpose (as long as you don’t surpass the 16 Msps speed limit).

[via Dangerous Prototypes]

Comments

  1. James Glanville says:

    Cool, but it doesn’t beat mine for cost/sample rate:

    http://i.imgur.com/31HTg.jpg
    http://i.imgur.com/mL2ko.jpg

    24Mhz, 8 inputs, £12.

    It’s a saleae clone, you just need a CY7C68013A dev board from ebay, a £0.10 eeeprom to switch out (the saleae software doesn’t like the normal one), some resistors and diodes for overvoltage protection., and whatever probes you feel like. I 3d printed the case on my prusa, but that’s not needed. I’m actually looking to sell some, so let me know at james.n.glanville@gmail.com if you’re interested.

    • Will says:

      How much? Details?

      • James Glanville says:

        (argh can’t reply to replies) I’ll be selling them for £40, with the cheapest shipping I can to anywhere.

        jlargentaye: while I have nothing to back this up with, I suspect it is to make it less confusing – a 20Mhz sampling rate logic analyser can probably not sample a signal of much better than 8Mhz (nyquist frequency = 1/2 sampling frequency, plus you have to take into account imperfections in the input). I would have a guess that companies wouldn’t like explaining why their 20Mhz logic analyser can’t sample 15 Mhz frequencies.

  2. F4R4D4Y says:

    YES!

    The power of a $4.30 development board.

    THANK YOU, TEXAS INSTRUMENTS.

    And nice build, by the way!

  3. jlargentaye says:

    OK, I’ve always wondered but never dared to ask. Why do logic analyzers mention “N million samples per second” as opposed to “N Mhz sampling rate”? Is there a nuance between sample per seconds and sampling rate that I’m unaware of, or is it just industry parlance?

    I find the “MHz sampling rate” to be clearer since everything elese in digital electronics uses the same terms. Because logic analyzers don’t, I wonder what I’m missing.

  4. I’ve got six launchpads (Plus 3 captouch addons, and the FRAM devkit) and have yet to really do anything with them… Maybe I should give this a try. :S

  5. naturetm says:

    Nice work as usual oPossum.

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