• State Resolved
  • Locked Locked
  • Replies 5 replies
  • Subscribers 30 subscribers
  • Views 351 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.

CC8520 behavior during OFF mode

Vladimir Tetelbaum
Intellectual 280 points
Other Parts Discussed in Thread: CC8520

We are trying to implement low power mode.  We are running CC8520 in host controlled mode.  We have ADC3101 connected to the cc8520.  

When we want to go into low power mode we issue PM_SET_STATE(0) from the host.

Question 1:  Does the CC8520 cycle through all power states on its way to OFF?  I.e. does it go from ACTIVE to LOW-POWER to INACTIVE to OFF as it relates to the control of the ADC?  Or does it jump directly to OFF?

Question 2: What happens to CC8520 outputs, specifically I2S signals, in OFF state?  We observe that both MCLK and BCLK are high in OFF state.  Is that expected?

Question 3:  In OFF state, in the Wireless Configurator, we insert a custom command: "p Reset 0".  We configure GIO2 as the audio reset pin.  We expect the signal to stay low in the OFF state, but it is not the case.

Question 4:  Is there a definite way to confirm that cc8520 is in OFF state by measuring things externally?

 

Thanks,

Vlad

  • 0
    TI__Expert 7160 points

    Hi Vladimir,

    1: Yes, it cycles through all states on its way to OFF.

    2: I connected the TLV320ADC3101EVM onto the PPW Audio EB and I observe that MCLK and BCLK goes low in the OFF state.

    3: I don't have to insert it as a custom command, it's present by default in the INACTIVE to OFF sequence when choosing the ADC3101 codec (to make it pop up in the Audio Device Customization panel you should remember to press the Reset all button). I observe that this signal stays low in the OFF state.

    4: No, not today, but this is good input, and we will look at implementing it.

    I don't know why you are experiencing strange behaviour. What hardware are you testing with?

    -Kristoffer

  • 0 in reply to Kristoffer S
    Intellectual 280 points

    We are using custom designed hw.

     

    How were you going into the OFF state -- host controlled command or using a button in autonomous mode?

     

    Vlad

  • 0 in reply to Vladimir Tetelbaum
    TI__Expert 7160 points

    Vlad,

    I try both ways with the same result: the clocks and audio device reset goes low.

    To make sure you are in low power mode you can run in autonomous mode and use a button to toggle OFF and ON and watch the status LED. Do you have the possibility to do this?

    -Kristoffer

  • 0 in reply to Kristoffer S
    Intellectual 280 points

    The problem was in our device customization code. We had a bunch of I2C code to handle graceful shutdown of ADC3101.  One of the commands had a typo in the I2C address.  It appears that CC8520 freezes when it tries to communicate with an non-existing I2C slave.

     

    Thank you for your help.

     

    Vlad

  • 0 in reply to Vladimir Tetelbaum
    TI__Expert 7160 points

    Vlad,

    The CC85xx performs a system reset upon a I2C bus error detection (missing acknowledgment, timeout etc.).

    Glad it worked out well!

    -Kristoffer