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CC1352P: LAUNCHXLCC1352P-2 how to use PA and SubG, 2.4G outputs?

SmartEnrg
Expert 1165 points
Part Number: CC1352P
Other Parts Discussed in Thread: CC1352R, LAUNCHXL-CC1352R1

Hi,

I'm excited and a bit confused to see LAUNCHXLCC1352P-2 schematic. If someone can help clarify the following for me please: 

There are 4 outputs/ RF interface ports -- 2.4G (P11), SubG (P12), PA (P13) -- all three marked as "DNM" for optional assembly; 

and routed via RF mux/ switch (U32) out to a single SMA (J7). Given that, my questions are: 

1) Is PA (pins 5 & 6) wired inside CC1352P to 2.4G and/ or SubG TX path internally? if so,how does the selection work? Please
     point me to section/s explaining this in the Tech Ref Manual (I'm referring to swcu185a).

     Trying to understand say for SubG operation - am I supposed to use P12 for receive and P13 for transmit?

2) Purpose/ advantage of using mux/ switch and (2.4G, SubG, PA) combined output via J7 or A1 is to have a common antenna 
     and be able to select RF signal chain? I imagine this switching happens automatically controlled by the stack, vs. user code 
     (using DIO28-30)?

     If that's the case - I suppose U32, J7/A1 are optional if user plans to populate P11 and/ or P12 along with P13. Perhaps not 
     even populate P13 if no PA is needed (sort of like "CC1352R" mode of operation).

Please advise. Thanks for your timely attention and help.

  • 0
    TI__Guru** 106705 points
    Hi SmartEnrg,

    On the LaunchPads all the RF in-/outputs are connected to the same PCB antenna through the RF switch (U32). The RF connectors are for the possibility of tapping into the various RF paths for testing and evaluation. There are no internal connection between the RF ports.

    Cheers,
    Fredrik
  • 0 in reply to Fredrik K
    Expert 1165 points
    Thanks Fredrik,
    (changing subject a bit) Re.: LAUNCHXL-CC1352R1 - can I use P11, P12 for two separate antennas (since there's no PA involved) there?
    Or the same design principle apply there as well? In which -- I'm supposed to use U28, RX_SWITCH and the combined antenna J7/ A1?
    Please advise.
  • 0 in reply to SmartEnrg
    TI__Guru** 106705 points
    You can use P11 and P12 for separate antennas both on the CC1352R and the CC1352P. For the CC1352P you would need a switch also since the PA port will be TX only and the other port (2.4 GHz or sub-1 GHz depending on which frequency band you are using the PA for) will be RX only.
  • 0 in reply to Fredrik K
    Expert 1165 points
    Hi Fredrik,
    I'm trying to send you a PM with a followup question to this - but it's failing in error. Saying something to the effect "You do not have access to this server". Please advice how I can send you a PM. Thanks.
  • 0 in reply to Fredrik K
    Expert 1165 points
    With reference to LAUNCHXLCC1352P-2
    My typical use case being SubG and BLE are operational at the same time - something like 6lowpan packets being routed/ streamed between SubG and BLE channels from time to time.
    Curious to learn since RF switch is juggling (multiplexing) traffic between SubG, 2.4G and PA -- how is multiplexing/ switching logic works?
    I mean,assuming switching between channels must be happening very fast in order to prevent/minimize potential for dropped (reception
    of) packets. Is there any concern over deterioration of RF performance in general, adverse impact on network bandwidth? Is there any characterization data available on this?
    Essentially, as part of my evaluation process, I'm trying to compare CC1352P with EFR32MG12P433F1024GM48 - in particular how 1352P work and perform since PA is Not dedicated to each band/ radio.
    Please advise. Thanks.
  • 0 in reply to SmartEnrg
    Guru 735695 points
    I suppose you can refer to DMM guide at dev.ti.com/.../
  • 0 in reply to SmartEnrg
    TI__Guru** 106705 points
    Hi SmartEngr,

    The switching time of the RF switch is much faster than the required switch speed between RX, TX and different frequency band. As such, the switching itself will not impose any limitation on the RF performance.

    Of course, operating multiple protocols at the same time will require time multiplexing which has to be accounted for when setting up the various connections. This will the same for any similar radio, including the one you mention.

    As YK says, I would recommend looking at the DMM guide.

    Cheers,
    Fredrik