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LAUNCHXL-CC1350-4: external LNA and PA control signals

Stevan Preradovic
Intellectual 905 points
Part Number: LAUNCHXL-CC1350-4
Other Parts Discussed in Thread: CC1190, CC1310

Hi,

I am working with the two 433 MHz 1350 Launchpads LAUNCHXL-cc1350-4. I modified them so that I use the SMA connector output for the 433 MHz link. Really great that SMA's are available on the Launchpad. I use a 433 MHz rubber ducky antenna.The system works well. Checked it all using SmartRF Studio. I managed to get the SimpleLink Academy Simple Tx and Simple Rx to work pretty much straight away.

The next thing I would like to do is to add some external components such as an RF switch, external PA and external LNA (in order to extend range). Please see the block diagram below.

This is where it got a bit hard for me. Im basically trying to understand how I can separate the Tx and Rx paths. From reading the technical documents it seems that external PA and LNA's can be controlled using IOs.

To do that I saw that in SmartRF studio I can go to "Configure Target..." and set that up. So i did.

I went back to my initial setup of having 2 launchpads communicating with each other. block diagram below of my experiment:

For the launchpad running Tx Packet (Launchpad 1) I setup the following:

For the launchpad running Rx Packet (launchpad 2) I setup the following:

If I understand this correctly when i press Start and run Packet Tx and Packet Rx on 2 different launchpads I should see some sort of transition from LOW to HIGH or HIGH to LOW on DIO30 when the PA is active on Launchpad1 and when the LNA is active on Lauchpad 2.

To observe that I connected an oscilloscope and had ch1 observe launchpad1 DIO30 and had ch2 observe launchpad2 DIO30. I got no transitions at all, it was constantly at logic '0', i couldnt see the control signals for the external PA and LNA toggled on either launchpads on DIO30. The system is working, the data is going through, plz see below (RSSI is high because the boards are 20 cm apart):

Could you please help me with this? What am i doing wrong here? Why cant i see any control signals for the external PA and LNAs on DIO30 on either launchpad? Thanks.

Stevan

  • 0
    TI__Mastermind 27145 points

    Hi,

    Your block diagram for LNA/PA with Switch looks OK to me.

    Yes, you are correct. You can configure the DIOs for controlling external LNA/PA operation.

    We used the following DIOs in CC1310+CC1190 Launchpad ( LAUNCHXL-CC1310-CC1190). Design files are available on our website. You can use the same DIOs for your control signals, so that you can use our tools without any changes.

    DIO30 for PA Enable

    DIO29 for LNA Enable

    DIO28 for HGM ( High Gain mode) - If you don't need this line, you can ignore it.

    Did you press Apply Button? If you don't press then it won't apply the settings.

    I tested those controls (DIO30) are I observed transitions.

    Please try again.

    You can test DIO settings ( High and Low levels) by selecting the Configuration as Input/output and set to appropriate states. But don't forget to Click on Apply Button.

    Thanks,

    PM

  • 0 in reply to PM
    Intellectual 905 points
    Hi PM,

    Ive definately pressed the Apply button in Configure Target window.

    1. Are you saying my Configure Target options should be set to Input/Output instead of Radio?
    2.Can you please explain a bit more the difference between Radio and Input/Output configuration?
    3. Do you have a link to the LAUNCHXL-CC1310-CC1190? Cant seem to find it.

    Thanks

    Stevan
  • 0 in reply to Stevan Preradovic
    TI__Guru**** 317180 points
    On the LAUNCHXL-cc1350-4 DIO1 and DIO30 are used to control the RF switch so you should select different IO(s) to control an external switch/ PA.

    You have to select "radio" as you have done to get the system to automatically control the PA/ LNA.

    The reference design for LAUNCHXL-CC1310-CC1190 is here: www.ti.com/.../swrc338
  • 0 in reply to TER
    Intellectual 905 points
    Hi TER,

    OK, Ive got this working now. Thank you to the both of you.

    Stevan