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  • Resolved

-Using a debugger with CC2540F256 increases the current draw on the board

Prodigy 20 points

Replies: 2

Views: 43

Hello,

I have a PCB that uses the CC2540 BLE chip from TI, using just this board has the current draw hovering around 20 microAmperes,
but when plugging in the CC Debugger from TI, this spikes the current draw up by almost 25milliAmperes.

Needed to know if this is an expected behavior or if this is a problem on our end.

For side details, only pins 1,2,3,4 and 7 are interfacing with the board.

pins 8, 9, and 10 have pull ups externally

pin 7 is pulled up externally.

  • Guru 240310 points

    - Connecting a debugger will always impact the current consumption.

    - Are you in debug mode when you measure current? 

    - Why the pull-up on pin 8-10 (I assume these are referring to the debug connector)

    - Which software are you running? 

     OOO until September 30th. If your thread is not answered by someone after 2-3 days after your last post, please repost with a link referring to your original post. 

  • In reply to TER:

    Found the issue was with the debugger. Tested with 5 samples.
    4 manufactured from China and 1 from US. (The conditions of the ones from China are unknown, but have stickers from Digikey)
    The US manufactured part were also purchased from Digikey and shows no current draw in idle
    The ones from China show massive deviations from each other, so I'm guessing there are damages internally, varying currents from 15mA to 90mA

    The pull ups are not on the debugger lines but on the PCB lines
    The debugger was in initial state, just booted and no mode set
    Current is measured by the power supply and not an IDE/software
    No software is being run, only a firmware

    tl;dr The debugger was most likely damaged.

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