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CC1120 + TRXEB + Packet Sniffer

Bob
Prodigy 80 points
Other Parts Discussed in Thread: CC1120, CC1101, SIMPLICITI

Hi,

I've been having trouble with the packet sniffer and the CC1120...

 

I was using the SmartRF04EB with the CC1110 for packet sniffing from other devices that have the CC1101 and I'm now interested in using the CC1120 to observe the improvement in sensitivity.

My problem is I can't get the packet sniffer to pick up any packets that I am able to pick up with my old SRF04EB setup...

 

The basic settings for both theCC1110 and the CC1120 are as follows:

Carrier frequency: 868.19989 MHz (CC1110) | 868.199951 MHz (CC1120)

Channel no: 0 (CC1110) | Default (CC1120)

Channel spacing: 199.951172 kHz (CC1110) | Default (CC1120)

xtal freq: 26 MHz (CC1110) | 32 MHz (CC1120)

Data rate: 19.9852 kBaud (CC1110) | 19.9852 ksps (CC1120)

RX filer BW: 101.5625 kHz (CC1110) | 100 kHz (CC1120)

Manchester enable: NO (CC1110 & CC1120)

Modulation format: GFSK (CC1110) | 2GFSK (CC1120)

Deviation: 19.042969 kHz (CC1110) | 18.981934 kHz (CC1120)

Tx power: 0 dBm (CC1110 & CC1120)

PA ramping: Off (CC1110 & CC1120)

 

Obviously its impossible to get the exact same settings because of the difference in crystal frequencies but I would still expect the above settings to work.

 

I had a quick look over all the registers (a lot!!!) for the CC1120 and couldn't see anything obvious that might be preventing me from picking up any packets.

 

Anyone any suggestions??

 

Thanks in advance,

 

Bob

  • 0
    TI__Guru**** 317180 points

    To clearify:

    Do you have a CC1120 EM connected to a TRX EB controlled by SmartRF Studio as sender and the CC1110 on a SmartRF04 running the package sniffer?

  • 0 in reply to TER
    Prodigy 80 points

    Sorry I didn't make that clear...

     

    I have my own hardware (two seperate devices). One is an End Device and the other is an Access Point (SimpliciTI) communicating with each other back and forth.

    When I use the SmartRF04 with the TI SmartRF Packet Sniffer SimpliciTI software I can observe the communications taking place.

    When I try to use the TRX EB with the CC1120 and the SmartRF Packet Sniffer software I can't pick up any packets at all.

     

    I make sure that I only have either the RF04 or the TRXEB plugged in when I am testing either one with the packet sniffer to avoid conflicts.

    The strange this is, I just noticed, I that when I use the actual Smart RF Studio Control Panel in 'RX Sniff mode' it is able to pick up traffic. But this is not ideal as at least the dedicated packet sniffer software breaks down the SimpliciTI packets so that they are easy to follow.

    -This makes me suspect it is actually the Packet Sniffer software itself that is at fault. (Version 2.15.2.0)

  • 0 in reply to Bob
    TI__Expert 4870 points

    Hi Bob,

    Did you try to export the register settings that is working in SmartRF Studio to use with the packet sniffer?

    To configure the packet sniffer for CC1120, you should set SmartRF Studio in "Packet RX" mode and then export the register settings.

    Normally the software that is handling Packet RX mode in SmartRF Studio is the same as the one used for the packet sniffer.

    Regards,

    Øyvind

  • 0 in reply to Øyvind K
    Prodigy 80 points

    Hi Øyvind,


    Yes I export the register settings in Packet RX mode. I have also tried using the settings from the RX Sniff mode as well with no joy.

    I have verfied that the hardware on both the TRXEB and the CC1120EM is working properly as I have done a PER test between the pair of TRXEB's with no problems.

    It's a bit of a mystery!

     

    Regards,

    Bob

  • 0 in reply to Bob
    TI__Mastermind 36395 points

    Bob, 

    The CC1120 uses a 32bit capable Sync detector where the CC1101 is only a 16bit detector and the default sync words in SmartRF Studio are not compatible.

    You need to make sure the Sync words are the same. Its pretty easy to change the Sync word on the CC1120 to the default on the CC1101 (write 91, D3, 91, D3 into SYNC0..3)

    /TA

  • 0 in reply to TA12012
    Prodigy 80 points

    Hey TA,

    The sync word was actually already setup as 91, D3, 91, D3 anyway.

     

    Just wondering if there are any settings that by default may be different for the two devices? I notice there are quite a few test registers I presume none of these should have that much of an affect?

     

    Regards,

    Bob

  • 0 in reply to Bob
    Prodigy 80 points

    I just noticed something unusual with the Smart RF Studio...

    Ok so i still can't see any packets in the Packet Sniffer software, but when I am in Packet RX mode on the Smart RF Studio I can see the packets coming in but they all seem a lot bigger than they should be, and they all give a CRC error. (With a reasonable RSSI of ~ -45dBm)

    Does the CC1120 calculate the CRC differently to the CC1101? Even if the CRC is bad I would still expect the Packet Sniffer software to pick up the packets as well.

    I have now setup the 2nd TRXEB in Packet TX mode with these settings and the Packet Sniffer works fine on the other. So obviously there is a mismatch between settings on the CC1101 and the CC1120 but nothing obvious... I would have thought once the basic settings like carrier frequency, deviation and bit rate are the same that it should still pick up some data??

  • 0 in reply to Bob
    Prodigy 80 points

    Actual forget that bit about the packets being longer than they should be and with a bad CRC... I had incorrectly changed the sync word to 16bits instead of 32 bits...

     

    But they do show up in the packet rx mode along side the packets from the CC1120 but for some reason the Packet Sniffer will only display packets from the CC1120!!