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Short range problem on using a set of EXP4618 EVM + CC1101EMK-433.

Seon-Woo Lee
Prodigy 30 points
Other Parts Discussed in Thread: CC1101, SIMPLICITI, CC1100E

Hi,

I am developing a kind of AP using a EXP4618 evaluation board + CC1101EMK-433 board.

For the task, now I am testing the modules. I have built and downloaded the example programs "Simple_Peer_to_Peer" of the SimpliciTI-CCS-1.1.1 package. (The sources are in the directory of /SimpliciT_root/Projects/Examples/EXP461X/Simple_Peer_to_Peer). One board was programmed with LinkTo sources, and the other was with LinkListen sources without any changes.

From several experiments with several CC1101 modules and EVMs, I found the range for normal operation (LED blinking) is around 30 cm (not meters but centi meters..).  If the distance between two systems is over 30~40 cm then both do not operate normally (not blinking red LED of Listener and green LED of Talker).

From several post, I found the normal range of CC110x transceiver is over 50 meters in LOS condition.. 

What should I do on hardware and/or software to fix this problem?

Thanks in advance..

senu

  • 0
    TI__Guru**** 317180 points

    Normally you need more than 1m between two CC1101 boards to be able to communicate (given max output power) because the receiver goes into saturation. When you have to have less than that to achieve link something is off. Check in the code:

    - Which output power the radio is programmed to

    - Which frequency the radios are programmed to.

    - Is it possible for you to use SmartRF Studio to control the EMs?

    - Check the RSSI values.

  • 0 in reply to TER
    Prodigy 30 points

    Dear TER:

    Thanks for your quick reply.

    First of all, I tried to test several times with the distance of over 1 meter..for this case both systems could not Link to each other..(we can find it from the state of LED blinking..) Anyway I think it is not saturation problem..

    For your first question about the output power:

    As I told i did not change anything from the given example code except ED address.. From the source I could find the power setting routine in the file " mrfi_f1f2.c: as:

     MRFI_WRITE_REGISTER( PA_TABLE0, mrfiRFPowerTable[idx] ); 

    From this, I might expect the the default power setting is maximum...(because idx=2, so PA_TABLE0 <= 0x60).

    And about the second question: How can I set the frequency of the CC1101 module? Does it means the logical channel? If so, the source told me it is zero in MRFI_Init() routine..

    Finally, unfortunately I do not have CC1101DK-433 hardware, so I think I could not use SmartRF Studio program to control the EMs..

    Could you please tell me another solutions for the problem?

    senu

  • 0 in reply to Seon-Woo Lee
    TI__Guru**** 317180 points

    I would assume that Simplicity out of the box uses 868MHz. If so you would get poor performance with 433MHz modules. Please check that you use the correct frequency.

  • 0 in reply to TER
    Prodigy 30 points

    Hi, TER:

    Could you please tell me which part of the sources in the SimpliciTI packages should I check for frequency setting for 433 MHz?

    I have tried to find the differences between two build  configurations of Eclipse for CC1101 and CC1100E_950, but I could not find something special..

    Also I have tried to search with the keyword "433" on the work space, I could not anything..

    Senu 

  • 0 in reply to Seon-Woo Lee
    TI__Guru**** 317180 points

    Sorry, I'm not familiar with Simplicity so I don't know. Please check the documentation and/ or the simplicity forum for more information.

  • 0 in reply to Seon-Woo Lee
    Genius 3370 points

    The file you need to look at is in the "SimpliciTI root"\Components\mrfi\smartrf\'radio-type' directory where 'radio_type' is CC1101 for instance. The specific file is the smartrf_'radio_type'.h file (like smartrf_CC1101.h) which contains register setting created by using the SmartRF Studio program. SmartRF studio has a register view which shows all of the register settings as well as a register export function. The register export function has a SimpliciTI settings template that is used to create the smartrf_'radio_type'.h file based on the radio settings in the Device Control Panel. One thing I have found is that the default SimpliciTI template may not have all of the registers exported that need to be. So I compared default template with the original SimpliciTI smartrf_'radio_type'.h file registers and added the registers that were missing.