• State Resolved
  • Locked Locked
  • Replies 3 replies
  • Subscribers 51 subscribers
  • Views 884 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Design with CC2540, consumption question

Thomas PINEAU
Prodigy 20 points

Other Parts Discussed in Thread: CC2540

Hi,

I am currently working on a project with a CC2540.

I would like to make sure I have no misunderstanding with the BLE protocole and/or the CC2540.

We will call the project: XX

What I want to do, is make a mobile phone (Master) exchanges data with my board XX (Slave).(of course when we will get some mobile phone BLE)

My board XX  will be power up by a cell coin, so my main preoccupation is the consumption.

What I  imagine to do is: to get my board in Power Mode 2 (sleep Timer ON) (0.9µA) all the time and every 10s my board do a "wake up" to check if the master (mobile) want to talk to XX. The mobile and XX has been coupled once before (1 time for ever)

è

 

If the BLE mobile is not active, XX goes back to Power Mode 2

If the mobile try to talk to XX,  a connection is establish and datas are exchanges.

Once the exchanges are done, XX is going back to Power Mode 2

 

Does my steps are realist?

By my understanding, with the excel sheet calcs consumption I found an average current of 3.5µA per hours which give me a battery life time of about 2000 days.

 

Does this make sense?

Thank you to give me your opinion on my case.

(I hope to have been clear enough)

 

  • 0
    TI__Expert 4060 points

    Hi Thomas,

    Your steps are correct when you are in connection. This is OK as long as your XX and the mobile phone remain within range of each other. If they go out of range, then the link will be dropped after a time out. Your device must then advertise (send packets on the 3 advertising channels) to try to re-connect (I'm assuming you want to automatically re-connect once you get back into range, if you have a manual connection, you can go to PM3). What period you will advertise at is up to you - the longer the period, the longer the re-connect will take, but the less power you use.

    Did you look at our application note on power calculation? If not, have a look at http://focus.ti.com/analog/docs/litabsmultiplefilelist.tsp?literatureNumber=swra347&docCategoryId=1&familyId=936, it should be useful to you.

    Best regards,

    Karl

  • 0 in reply to Karl T.
    Prodigy 20 points

    Hi Karl,

    Thank you very much for your reply.

    Our  divice XX will work with an application on the mobile. When this application is turn off, the BLE link will be disconnected.

    So for me, having the device out of range or the application in the mobile turn off, the status for XX must be the same =>polling every 10 sec to verify if the mobile is here and if it is trying to speak to XX.

    We consider that the application will be turn-ON only 10% of the time per day.

    I want to make sure I understand well the BLE Functioning.

    The mobile is the master and it decide if it wants to upload/download datas from XX.

     

    Thank you for you support

  • 0 in reply to Thomas PINEAU
    TI__Expert 4060 points

    Hi Thomas,

    This basically means you will be in advertising mode most of the time, and then only be in a connection when you are actually communicating with the phone. We are planning to put a calculation of advertising mode into our Excel sheet, but have not had time to do so yet.

    It is not so different from connected mode, but advertising requires you to hop on the three advertising channels.

    Best regards,

    Karl