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Mode Transition time for CC2541 from Active to PM3

praba karan
Prodigy 120 points
Other Parts Discussed in Thread: CC2541

Hello

I have few questions. can you please help me to get the solution.

1.How much time does CC2541 takes to switch form Active Mode to PM3 or PM2. The CC2541 data sheet contains wakeup time, and leakage current values in PM modes and Active modes.

If i want to put my CC2541 from active mode to PM3, then how much time it takes to switch the mode.

2. CC2541 has 8051 and BLE on a single chip. can i enable both 8051 and BLE Tx/Rx separately, That means while data acquisition from sensors connected to CC2541 i need to put the BLE in low power mode , once the sensor reading is completed i wanted to wake up the BLE section and want to transmit the data.

Work                                                 Active Mode                      PM2 or PM3

Data acquisition                            8051 of CC2541                BLE Modules ( Tx/Rx)

Transmission/ Reception             BLE Modules ( Tx/Rx)       8051 of CC2541

Is that above scenario is possible..

Thanks in advance

E.Prabakaran

  • 0
    Expert 2500 points

    Hi,

    1.  you need to enable power saving into your firmware. Once OSAL determines that there is no event pending then it'll put device into sleep mode immediately, might take around 5-10 seconds. 

    2. I think that's not possible manually, because you need to maintain connection even during data acquisition. During connection if there is nothing to set, OSAL automatically  reduces clock frequency to reduce power.

    you need to allow OSAL to do that. Put following in your initialization code:

      HCI_EXT_ClkDivOnHaltCmd( HCI_EXT_ENABLE_CLK_DIVIDE_ON_HALT );

    ----------------------------------------------------------------------------------------------

    Click "Verify" once your question is answered.

  • 0
    TI__Expert 6995 points

    Hi Praba,

    1. It takes around 20 us for the CC2541 to enter PM3 from active mode

    2. BLE is a synchronous protocol, so you have to obey the connection event timing. It would be best to schedule your data aquisition just after a connection event and use slave latency if you need extra time. 

    Peder