• State
  • Locked Locked
  • Replies 5 replies
  • Subscribers 18 subscribers
  • Views 532 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.

Inquiry on CC1101 calibration

z mz
Prodigy 60 points
Other Parts Discussed in Thread: CC1101

My CC1101 chips are required to sleep and wakeup every 2 seconds. The chip is required to Rx several packets and Tx several packets (250kbps) every wakeup (several milliseconds).

The chip performs a manual calibration each time after the Rxs and Txs and just before the chip goes sleep. This means that when a chip wakes up, it goes to Rx or Tx directly without manual calibration.

These chips are installed in a location where there are large metal objects moving around.

Through some observations (I am not too confident about this observation, but my CC1101 tranceivers do get blackout for some time constantly), I find that when there're some environmental changes involved (the metal objects moves away, or moves close), there's a very small probability that the chip is blackout for some time (several seconds, up to 10+ seconds, this is also roughly the time that the metal objects moves away or moves close), even when the RSSI is around -60dB (before and after the blackout). 

Is that possibly due to the fact that I calibrate them after Rx and Tx? If I move the calibration right after wakeup and before the Rxs and Txs, will this possibly help?

Thanks for the help. All I want to know is whether I did something wrong with calibration. If calibration is fine, then I probably need to find other causes.

 

  • 0
    Expert 2840 points

    Hi,

     

    I guess the only thing you could do is try after you wake up from sleep, however since you do mention poor reception when large metal objects are in the vicinity, this could also be a very good reason for it as they may absorb enough of the RF to cause reception problems.

    M

  • 0
    TI__Expert 4435 points

    The attached file should help you set up and calculate your WOR for the CC1101.

    TI Low Power Wireless Group

    CC11xx_WOR_Calculator.xls
  • 0 in reply to citizen
    Prodigy 60 points

    M MARIN said:

    Hi,

     

    I guess the only thing you could do is try after you wake up from sleep, however since you do mention poor reception when large metal objects are in the vicinity, this could also be a very good reason for it as they may absorb enough of the RF to cause reception problems.

    M

    Hi thanks for the reply.

    However, my problem shouldn't be the object blocking. It is because from my observation, the blackout is sometimes correlated to the MOVING of objects but not the object itself. I.e., when the objects stopped moving, we can still receive packets & the RSSI is quite ok to receive.

    Since the blackout is quite random and takes long time to observe, each testing takes days and even weeks to see the results. That's why I am asking here and I'll try and hope to get things right first.

     

     

  • 0 in reply to RRS
    Prodigy 60 points

    RRS said:

    The attached file should help you set up and calculate your WOR for the CC1101.

    TI Low Power Wireless Group

    Hi, thanks for the reply.

    My problem isn't related to WOR though. We have a quite accurate synchronization scheme for waking up / sleeping.

    From other TI posts I can guess that the calibration of CC1101 isn't necessary if the temp & voltage don't change much. So does it mean calibration doesn't matter too much in my situation (provided that those metal objects don't alter the environment temp)?

  • 0 in reply to z mz
    TI__Genius 12480 points

    Did you ever solve this problem?

    -Jonas