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CC2650STK demo firmware + Android app, IMU not working

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My CC2650STK just arrived, and I'm checking it out with the TI demo Android app.  The humidity, noncontact temperature, barometric pressure, and lux sensors all behave like they should, but the app doesn't show sensible data for acceleration, rotation, or magnetic fields.  All those fields show zero.  I've updated the CC2650STK firmware to revision 1.12 (Jun 23 2015) using the Android app.  The Android app is revision 2.3.  I'm running it on a 1st-gen Moto X with Android 4.4.4.  

 

Is this a known software issue, or do I have bad SensorTag hardware?  

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My CC2650STK just arrived, and I'm checking it out with the TI demo Android app.  The humidity, noncontact temperature, barometric pressure, and lux sensors all behave like they should, but the app doesn't show sensible data for acceleration, rotation, or magnetic fields.  All those fields show zero.  I've updated the CC2650STK firmware to revision 1.12 (Jun 23 2015) using the Android app.  The Android app is revision 2.3.  I'm running it on a 1st-gen Moto X with Android 4.4.4.  

 

Is this a known software issue, or do I have bad SensorTag hardware?  

 

One thing I've heard is that the IMU doesn't work properly when the supply voltage has dropped below 3V. I know you only just got the SensorTag and would expect the coin cell to fresh, but the original firmware had atrocious power consumption...

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The SensorTag shipped with a plastic film over the battery, so it shouldn't have run down already, unless that original firmware was *really* power hungry.  Was the power consumption fixed in the 1.12 firmware?  

 

I tried a replacement battery, and I did see a few updates in the Motion Data section, with accelerometer, gyro, and magnetometer all showing some non-zero values, but then they all froze.  After disconnecting and reconnecting, it's back to showing all zeros under Motion Data.  Removing the battery and putting it back in again, I get the same behavior.  It looks like 9 updates of Motion Data come through with a 1000ms period, and then the Motion Data freezes.  

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The SensorTag shipped with a plastic film over the battery, so it shouldn't have run down already, unless that original firmware was *really* power hungry.

You're right, the power won't have started to run down until the plastic strip was removed. Unfortunately I wasn't exaggerating when I called the power consumption atrocious. People have reported draining the battery enough to affect the IMU within a couple of days.

 

Was the power consumption fixed in the 1.12 firmware?

I think you might need a newer firmware than that. Are you updating over-the-air from a phone or with a Debug DevPack?

 

I use the DevPack, and the SensorTag sample in the BLE Stack 2.1 has been updated with the power consumption fixes. It's also available as a prebuilt hex file for programming with SmartRF Flash Programmer V2 from here: https://e2e.ti.com/cfs-file/__key/communityserver-discussions-components-files/912/CC2650SensorTag_5F00_BLE_5F00_App_5F00_v1_5F00_20.hex

 

If you need to update over-the-air then I'm not sure what version is available.

 

I tried a replacement battery, and I did see a few updates in the Motion Data section, with accelerometer, gyro, and magnetometer all showing some non-zero values, but then they all froze.  After disconnecting and reconnecting, it's back to showing all zeros under Motion Data.  Removing the battery and putting it back in again, I get the same behavior.  It looks like 9 updates of Motion Data come through with a 1000ms period, and then the Motion Data freezes.

That rings a bell, I think older firmware had problems with the wake-on-motion feature. The IMU would give output for a while, but then stop and never restart.

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I checked the battery voltage at the two exposed pads on the PCB, and the lowest reading I saw while connected to my phone was 3.011V.  My Fluke 77-IV is only so fast, so it's possible there are dips a bit below that.  Anyway, low battery voltage doesn't seem to be a likely cause, and I'm leaning toward a firmware 1.12 bug.  

 

Unfortunately, I didn't buy the SensorTag DevPack, so I can only update the firmware via Bluetooth and the Android app.  Hopefully, TI will update the app soon.  

 

About the SensorTag DevPack---can the XDS-110ET included on the MSP432 LaunchPad possibly be used as a debugger for the CC2650STK, connectors notwithstanding?  If so, I'd rather add an MSP432 LaunchPad to my collection.  

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About the SensorTag DevPack---can the XDS-110ET included on the MSP432 LaunchPad possibly be used as a debugger for the CC2650STK, connectors notwithstanding?  If so, I'd rather add an MSP432 LaunchPad to my collection.

 

Yes, but the necessary modification is difficult at present.

 

The emulator firmware doesn't support cJTAG (only SWD and JTAG), while the CC26xx doesn't support SWD (only JTAG and cJTAG). That means that full four-wire JTAG is the only option that will work right now. The problem is that the launchpad only exposes pins for SWD and cJTAG rather than the full JTAG pinout used with the on-board target.

 

To add a JTAG cable you need to tap into one of the traces on the PCB by scraping off the soldermask and tacking a wire to the trace. The other connections are exposed at J103 and one is on a terminal of S101. See these posts on TI's forum for more details:

 

XDS110 from MSP432P401R Launchpad for CC26xx/CC13xx

MSP432P401R LaunchPad External Target Mod (See the detailed instructions in the PDF)

 

I have a sneaking suspicion that TI might add cJTAG support to the XDS110 on the Debug DevPack to fix the issue with debugging while using the serial flash. If they do there's a slim chance that the same might be added to XDS110-ET. That would make it far easier to use the MSP432 launchpad with the SensorTag, because only connections to J103 would be required. None of this is confirmed, and it'll be at least a few months before the next major XDS110 firmware update. I heard predictions of October from TI, but their toolchain updates are prone to slippage.

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Sounds like I should add the Debug DevPack to my to-buy list!  

 

By the way, I'm seeing other places that the IMU freezes are commonly seen with the version of the firmware and Android app I have.  Hopefully, TI issues an update soon.  

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I also observed the freezing issue after a few seconds into the first time playing with the sensortag and the android app. Good to know it's not physically broken.

 

Sent from my SM-N9005 using Tapatalk

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