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MSP430FR6989: Definitive Guide on Testing LPMs on Launchpads

Mehmet Cagri Kose
Intellectual 405 points
Part Number: MSP430FR6989
Other Parts Discussed in Thread: ENERGYTRACE

I create this thread not to ask question but to answer one: How the h*** do I test and prove low power MSP430's are really low power. I have a FR6989 launchpad and it was really frustrating to try low power modes and seeing 2 mA on Energy Trace. Energy Trace was also showing high current with intended LPM. Obviously I checked everything on the internet but couldn't find complete set of instructions on how to prove those legendary sub-1microAmpere values.

Energy Trace or variants: Looks good, doesn't work for my Low Power mode trials. I had reliable 2 mA anytime I used those tools. Too late I realized it was taking powering the debug board also(not only our board). I have read somewhere that Energy Trace should subtract the debug related currents but my brain might be playing games to me. People are saying use Energy Trace mode without jumpers but without jumpers, I can not start Energy Trace, at least not in CCS Theia. Reliable way of starting Energy Trace and Energy Trace++ with CCS Theia is starting debug mode properly with all jumpers connected, then Energy Trace buttons become active.

Instructions for Proving Current Draw less than 1 uA

1. Remove all the jumpers

2. Power your board with 3.3 V battery(or close ones, like 3.7 Li-Ions etc). Using 5V spends more power due to voltage regulator.

3.  Use one of the examples provided by TI. I had used msp430fr69xx_lpm3_03 example. Build and load release mode of your software. To be honest, I didn't test debug version in my successful run because it is too late in Europe.

3. Put your multimeter properly on your battery cables.

4. Enjoy your test with your own multimeter. I shed tears when I saw 0.8 uA on the LCD screen. 

Next Test: Trying the same with coin battery and then, trying even lower power modes.

Now I can sleep well. But, can someone give me link to a definitive guide on how to properly see the same results in Energy Trace modes(whether it works with Theia version also.). Step by step, like I am 5 years old. I can definitely make a case that TI is obscure on these low power guides and there are tons of questions on forums with high power on  lower device/examples. Most of those threads have obscure advice or unanswered.

  • 0
    TI__Mastermind 36420 points

    Sorry, to hear that.

    Here is the doc for you to refer to use Energytrace: https://www.ti.com/lit/an/slaa603/slaa603.pdf

    From my experience, enegrytrace can get the accuracy with ~0.1uA. The key point lies on the hardware setting. Please remove all the jumpers on board, except 3V3 and GND. Then, you can enable energytrace and make a try. It should work well. If there is any further problems, please let me know.

  • 0 in reply to Eason Zhou
    Intellectual 405 points

    I assume the order would be 

    1. Download the software

    2. Remove the said jumpers

    3. Start the Energy Trace.

    Observations

    1. I can not start Energy Trace/Energy Trace++ before starting the debug process, in CCS Theia(with all jumpers connected). Those buttons are simply grayed out

    2. After I start debug process and it stops at the entrance(just before stopping watchdog timer), Energy Trace button becomes active. Then I can start
    3. After step 2, removing 5V pin specifically seems to break USB connection-like disconnecting. Therefore, I removed 5V before any attempt on power measurement permanently.
    4. Energy Trace isn't useable before an active debug session, so I need SpyByWire and UART connections connected before debug session. After debug session and Energy Trace activated, I can remove those 4 pins I mentioned, continue the code and see the power measurement as I was seeing in multimeter with battery.
    5. I can not start debug session without jumpers(makes sense), so I remove them mid-debug.

    My questions are

    • Is it the formal order(starting debugger first, then Energy Trace, then removing jumpers and measuring) for power measurement?
  • 0 in reply to Mehmet Cagri Kose
    TI__Mastermind 36420 points

    Actually, you should not enable debug when using energyTrace. It will add more current.

    I install CCS theia and try to look into your problem. However, I seems meet problems when improting project.

    Anyway, I would suggest you use CCS. You can enable the energytrace without enabling debug.

  • 0 in reply to Eason Zhou
    Intellectual 405 points

    I now have 3 different CCS versions. CCS 6.1.3 for just being able to work with "TI-RTOS for MSP430" properly. One is the latest regular CCS version for Energy Trace/++ without debug mode. CCS Theia for keeping up with the latest IDE.

  • 0 in reply to Mehmet Cagri Kose
    TI__Mastermind 36420 points

    I assume Energytrace should work on latest CCS right? If yes, I will close this thread.

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