• State TI Thinks Resolved
  • Locked Locked
  • Replies 13 replies
  • Answers 1 answer
  • Subscribers 53 subscribers
  • Views 1382 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.

CC1312R: CC1312R Packet RX get CRC error

user5788052
Prodigy 95 points
Part Number: CC1312R

Hi Ti friend,

We use TI LAUNCHXL-CC1312R1 EVB board, control my device by JTAG in the shielding room.
see Attached environment setup

device02 TX setup

device01 RX setup

Why received packet's rssi is -93dBm, but CRC error ??

anothor test, device01 power on, Continuous RX RSSI -101dBm see Attached Screenshot.

  • 0
    TI__Guru**** 317180 points
    - If you place the LPs on the desk, do you get communication then?
    - Do you get a different result if you change the frequency?
    - When you measure the RSSI, is the TX device on then and is this inside the shielded box? If this is measured inside the shielded box and any known TX is off then you have a very high power noise source somewhere that impact your measurements.
  • 0 in reply to TER
    Prodigy 95 points

    - If you place the LPs ( mean LaunchPad ?? ) on the desk, do you get communication then?
    OK, can communication , but as the attenuator increases, packet error rate increases & show CRC error.

    RSSI: -86.4dBm RX OK.

    RSSI: under -89dBm CRC error

    - Do you get a different result if you change the frequency?
    Use 915M as same.

    - When you measure the RSSI, is the TX device on then and is this inside the shielded box?
    TX device no use shielded box.

    If this is measured inside the shielded box and any known TX is off then you have a very high power noise source somewhere that impact your measurements.

    RX device measured inside the shielded box and any known TX is off.

    So,Is it possible is in band noise on my device?

     

  • 0 in reply to user5788052
    TI__Guru**** 317180 points

    I measured background noise in the office with a CC1312 launchpad. Since we are in a open office with several apps engineers we normally have a fairly high RF traffic on some frequency band. So what you measure in a shielded room is an unexpected high background noise. 

    Is the launchpad unmodified? Is all components that should be there in place towards the antenna? (In some cases I have seen mechanical damage on boards).

    Do you get the same with the other launchpad you have?

  • 0 in reply to TER
    Prodigy 95 points

    Hi TER,

    I measured background noise in the shielded room with a CC1312 launchpad and my device 868M module.

    Difference is as follows:

    CC1312 launchpad noise floor

    My 868M module noise floor

  • 0 in reply to user5788052
    TI__Guru**** 317180 points
    Have you done conducted measurements (sensitivity/ output power) before starting radiated testing?

    Please refer to www.ti.com/.../swra603 for debugging.
  • 0 in reply to TER
    Prodigy 95 points

    Hi TER,

     My test environment, conducted measurements Device02 TX output power 9.95 dBm

    and Device01 Rx sensitivity, RSSI -104.9 dBm.

    Measurements RX sensitivity

    conducted : RSSI -104.9dBm no CRC error.

    Air : RSSI  under -89dBm CRC error

    Any suggestions? Thanks you.

  • 0 in reply to user5788052
    TI__Guru**** 317180 points
    Ok, this indicate the the conducted performance is close to expected.

    What antenna is device01 using and is this antenna tuned?
  • 0 in reply to TER
    Prodigy 95 points

    Hi TER,

    Device01 use PCB antenna.

    This antenna tuned S11 & circuit.

    Circuit, remove C36, look the antenna of S11

    S11, Marker2  -14.9dBm  at -14.9dB

    Thanks for your help.

  • 0 in reply to user5788052
    TI__Guru**** 317180 points
    What is the impedance and VSWR @868 MHz?

    Do you have a picture showing how/ where you soldered on the semirigid cable used for the tuning? Could something in the test setup detune the antenna?

    From the results it looks like the tuning is off.
  • 0 in reply to TER
    Prodigy 95 points

    Hi TER,

    What is the impedance and VSWR @868 MHz? 

    Marker2@868M, S11 and smith chart

    Do you have a picture showing how/ where you soldered on the semirigid cable used for the tuning?

    Could something in the test setup detune the antenna? 

    Can you give an example?

    Any suggestions?

    Thanks you.

  • 0 in reply to user5788052
    TI__Mastermind 33100 points
    The measurements show that the antenna is tuned at 868 MHz.

    Have you done the same measurements whilst the PCB is in the final casing/housing which possibly could de-tune the antenna.
  • 0 in reply to RGW
    Prodigy 95 points

    Hi RGW,

    YES, The measurements already in the final casing/housing.

  • 0 in reply to user5788052
    TI__Guru**** 317180 points
    We discussed this some and are wondering if the orientation of your antenna have an impact since the antenna is not omni directional. Could you try different rotation of your board?