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AWRL6432: Exit deep sleep latency?

James Austrial
Expert 4160 points
Part Number: AWRL6432


Hi,

We know the UART RX can wake up the system from deep sleep mode. The flow may like:

UART RX -> Trigger wake up -> Resume clock , power -> UART start to get data

One question is how fast the UART receiver can start to decode the data bit (LSbit) within certain time after AWRL6432 is back from deep sleep mode?

We do not know how long is the wake up latency, any idea? 

  • 0
    TI__Expert 3525 points

    Hi James, 

    We are looking into this and will provide an update by end of week.

    Best Regards,

    Kevin 

  • 0
    TI__Genius 13235 points

    Hi James,

    Have you had a chance to look at our power optimization techniques app note (https://www.ti.com/lit/pdf/swra754)? As mentioned in that document, it typically takes around 2ms to reinitialize the SW after coming out of a deep sleep period, depending on the options selected.

    Thanks,

    Clinton

  • 0 in reply to Clinton Rodgers
    TI__Expert 4160 points

    mmm... 2ms wakeup latency is very long and that means the external MCU can't expect AWRL6432 to get first UART data completely.
    It looks to me the follow protocol needs to be implemented:

    Step1: External MCU send UART magic packets to wakeup AWRL6432 and waiting for ACK from AWRL6432.

    Step2: AWRL6432 is wake up by magic packets and execute necessary procedures.

    Step3: AWRL6432 send ACK to external MCU to notify it's ready to get UART data.

     How do you think?

  • +1 in reply to James Austrial
    TI__Genius 13235 points

    Hi James,

    Could you provide more background on what you are experiencing? Have you put the device into deep sleep and used the UART to wake the device up and missed data? What data are you trying to send to the device?

    I also wanted to point you to the power modes driver example in the mmWave SDK 5.2. You can find it in the directory below.

    <install dir>\MMWAVE_L_SDK_05_02_00_02\examples\drivers\power\power_modes

    Thanks,

    Clinton

  • 0 in reply to Clinton Rodgers
    TI__Expert 4160 points

    Hi Clinton,

    Customer expects the xWRL6432 can latch UART data as soon as possible. For example, xWRL6432 senses the UART edge and wakeup immediately. After few uS, it starts to decode the first bit from UART data.

    From MMWAVE_L_SDK_05_02_00_02\examples\drivers\power\power_modes code, it looks the above scenario can't be met and it would take few mS to wakeup the whole device and then start to get UART data correctly.

    We can close the ticket if my understanding above is correct.