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CC2650STK: Battery monitor and HDC1000

A K
Intellectual 895 points
Part Number: CC2650STK
Other Parts Discussed in Thread: HDC1000, , OPT3001, HDC2010

Using SensorTag Rev 1.3.0, stack 2.1.1, project SensorTag.

I modified the firmware to transmit at 5 dBm and 1.5s ADV interval. I have enabled the humidity sensor task and the 1s periodic clock in all GAP states. AONBatMonBatteryVoltageGet() is called on expiration of the periodic timer. I am reading a voltage 200 mV lower than the actual 3V on the Panasonic CR2032 cell. The difference is greater than 300mV when the cell voltage is 2.85V and the humidity sensor fails. I can attribute that to a 2.3V drop in battery voltage when battery and humidity sensor is being read and ADV events. I also set up the ADV event notice and read the battery after receiving it but it made it worse.  

This significantly reduces the usable range of CC2650STK (in addition to the HDC1000 min voltage of 2.7V) . Is there a way to read the battery in the idle task? Any other suggestions appreciated.

Thanks!

  • 0
    TI__Guru** 105180 points
    You can read the battery in any RTOS task, however, reading it in the app task is not going to change the state of the system since it's the lowest priority task that performs any processing. The batt voltage will drop after a load and take some unloaded time to return to the "relaxed" state.

    I'm not sure what you mean by "significantly reduces the usable range of CC2650STK". You are transmitting at the max 5 dBm output power.

    Best wishes
  • 0 in reply to JXS
    Intellectual 895 points

    CC26xx and OPT3001 work down to 1.8V, motion sensor 2.4V and HDC1000 2.7V. With a 2.8V battery voltage and the dip caused due to load, the effective operational battery range is >2.8V to 3V vs. 2.4V to 3V. The life is significantly reduced for a customer who needs humidity. 

    Does TI plan to use the HDC2010 sensor for future builds so all sensors are functional down to 2.4V?