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MSP430F5308: Monitoring battery voltage without addtional /external components

Part Number: MSP430F5308

Hi,

I am making a new design with CR2032 battery(about 3V) that uses MSP430F5308 which has ADC (and much more) and I would like to understand what is requied in terms of hardware and Firmware in order to check if battery level is lower then 2.5V (or better 2.7V)

I understand from several posts that it is possible to measure battery level (VCC) by comparing some internal reference (2.5v or 1.5V), my questions are:

1) Is there some reference code that I can use for this?

2) Does the hardware need to take this into account? or this is all internal firmware code only ?

Thanks

  • Hi Yaniv,

    thanks for your question!

    1) We provide example which you can use to start with your implementation. You might need to adapt certain things to fit your application needs but those are a very good starting point.

    You can find those in the TI Resource Explorer, either online or within CCS, just browse for the device and select one of multiple ADC examples. There are some that show how to convert and analog value and compare the value against an internal reference.

    2) Can you elaborate on this? You need to of course connect the voltage you want to measure properly to the ADC input and make sure it's in the input scale of the ADC. Still, the code we provide is handling firmware only and assumes the correct connections (those are indicated in the code, even though you can of course use different channels as well).

    Please let me know in case you'll need anything else.

    Best regards,

    Britta

  • Hi Britta,

    Thanks for the answers.

    This is a coincell battery device in the  range of  2V - 3.1V, my intrest is just to know when the battery goes belllow 2.5V.

    So if I understand correctly your answer in section 2, the host can't measure using internal muxing the VCC level, I will require to connect VCC to ADC input. 

    somthing like this?

    Regards,

    Yaniv

  • Hi Yaniv,

    according to the specification of MSP430F5308 it is able to measure AVCC at channel 11. Look for VMID:

    I think your additional hardware is not mandatory.

    Regards

    Christoph

  • Hi Yaniv,

    if you'd really only need to detect if your supply voltage falls below a certain level you could check if using a comparator input might not already be sufficient for your application.
    In case you're concerned about resets due to low Vcc you could of course also use the integrated voltage supervisor and voltage monitors . You'll find details in the device family User's Guide.

    Best regards,
    Britta
  • Hi Yaniv,

    note that I am closing this thread due to inactivity.
    Please respond back in case your question hasn't been answered yet. Any reply to this thread will reopen it for further discussions.
    Also, verifying the answers which helped you can be of benefit for other users researching the same issue. Please mark the according posts so that others can benefit from it.

    Thanks and best regards,
    Britta

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