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CC2650MODA: LaunchXL-CC26X2R1 measuring current on external custom board with CC2650MODA using EnergyTrace

Part Number: CC2650MODA
Other Parts Discussed in Thread: LAUNCHXL-CC26X2R1, ENERGYTRACE

Hi,

I'm trying to use the LaunchXL-CC26X2R1 board to measure the current consumption of a custom board which uses the CC2650MODA.  I can successfully use the LaunchXL to program the custom board (using the RF Flash programmer) and debug the sensor controller (using the SensorController Studio).  I have the LaunchXL connected to the custom board using the 10pin ribbon cable.

When I remove the 3V3 and RXD jumpers, the currents are zero.

When I remove the "XDS110 Power" jumper, the currents are implausibly high.

With the 3V3, RXD and "XDS110 Power" jumpers in, I see pulses of current every 100ms.  I do have a task running on my custom board with a period of 100ms. When I change that period to 200ms, I can see by LED toggles that it has changed, but my current waveforms do not change.

My questions:

1) should it be possible to use the LaunchXL and EnergyTrace to measure the current on an external board connected by ribbon cable?

2) what should the jumper settings be?  The SWRA478 says to take them all out but that makes my current readings zero.

3) what configuration option or jumper tells the LaunchXL to measure the external current and not the current of the on-board CC26X2R1?

Thanks,

Jim

  • Hi Jim,

    Here is the CC26x2R LaunchPad Getting Started Guide and SWRA478.

    1) Yes, please confirm that you are connecting the ribbon cable to XDS110 Out and that the Power Jumper has XDS110 Power selected.

    2) All XDS Jumpers should be removed.

    3) If the jumpers are removed then the on-board CC26X2R1 will not be drawing any current.  By having 3V2 & RXD connected, the on-board CC26X2R1 will be active and thus causing interference with measurements.  If the Power Jumper is set to XDS110 Power and the XDS110 Out ribbon cable is properly connected to the custom board, then the custom board can be programmed.  However, current measurements will only be accurate if free-running the target inside the debugger or removing debugger pins (i.e. only having VCC/GND connected).  Otherwise you will see approximately 1.2 mA due to an active debug connection.  It is possible to start an EnergyTrace Stand-alone Measurement Mode so that the debugger is not involved.

    Regards,
    Ryan

  • Hi Ryan,

    This resolved my issue.  I connected just the 3V3 and GND to my target (not the full 10 pin ribbon cable) and put the "XDS110 Power" jumper in and now am getting sensible readings. 

    Thanks!