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CC110L: CCA implementation in CC110L

Part Number: CC110L
Other Parts Discussed in Thread: TEST2


   I am trying to understand the CCA mode of CC110L. I Have few Queries related to implementation of CC110L CCA mode.

    First i will state my register setting related to CCA implementation

    my register setting related to this mode

    MCSM1 = 0x3F

    AGCCTRL2 = 0x43 [33 dB]

    AGCCTRL1 = 0x40 

    IOCFG2 = 0x09 

So basically i have set the threshold value to 33 dB and i am observing status of GDO2 on oscilloscope to check whether my current channel is clear on not.

HIGH :- Channel Clear

LOW :- Channel Busy


My Queries

1> I have a customized CC110L Board and i have set it on Channel 0, Rx mode, with above CCA mode setting. when i observe the GDO2 pin of this module i see some random HIGH to Low transition

but no RF communication is going on near by on channel 0.


2> Now with TI CC110L module i send some random data on channel 0 at 10 ms interval. when i observe GDO2 of my custom Board it shows high to low transition (indicating some communication is going on on channel 0) at 10 ms rate which is correct but i also see some random High to Low on GDO2 also which should not be there.


3>Now even if i switch the channel on which TI's CC110L module is sending data to 0,1,2,3,4 still the GDO2 pin of my custom Board which is on Channel 0 shows Channel 0 is busy exactly same as when TI's CC110L module was sending data on channel 0.


Any help ?


Thanks in advance. 


 NOTE :-----------------------------------------------------------------------------------------------------------------------------------

My complete settings are as below

const u8 uc_CC110L_Config[48]=
0x09, // IOCFG2 GDO2 Output Pin Configuration
0x2F, // IOCFG1 GDO1 Output Pin Configuration
0x07, // IOCFG0 GDO0 Output Pin Configuration 
0x4F, // FIFOTHR RX FIFO and TX FIFO Thresholds
'G', // SYNC1 Sync Word, High Byte
'N', // SYNC0 Sync Word, Low Byte
61, // PKTLEN Packet Length
0x0D, // PKTCTRL1 Packet Automation Control
0x05, // PKTCTRL0 Packet Automation Control
0x00, // ADDR Device Address
0x00, // CHANNR Channel number
0x06, // FSCTRL1 Frequency Synthesizer Control
0x00, // FSCTRL0 Frequency Synthesizer Control
0x10, // FREQ2 Frequency Control Word, High Byte
0xA7, // FREQ1 Frequency Control Word, Middle Byte
0x62, // FREQ0 Frequency Control Word, Low Byte
0xCA, // MDMCFG4 Modem Configuration
0x83, // MDMCFG3 Modem Configuration
0x12, // MDMCFG2 Modem Configuration
0x22, // MDMCFG1 Modem Configuration
0xF8, // MDMCFG0 Modem Configuration
0x35, // DEVIATN Modem Deviation Setting
0x07, // MCSM2 Main Radio Control State Machine Configuration
0x3F, // MCSM1 Main Radio Control State Machine Configuration
0x18, // MCSM0 Main Radio Control State Machine Configuration
0x16, // FOCCFG Frequency Offset Compensation Configuration
0x6C, // BSCFG Bit Synchronization Configuration
0x43, // AGCCTRL2 AGC Control
0x40, // AGCCTRL1 AGC Control
0x91, // AGCCTRL0 AGC Control
0, // not used
0, // not used
0xFB, // RESERVED_0X20 Use setting from SmartRF Studio
0x56, // FREND1 Front End RX Configuration
0x10, // FREND0 Front End TX Configuration
0xE9, // FSCAL3 Frequency Synthesizer Calibration
0x2A, // FSCAL2 Frequency Synthesizer Calibration
0x00, // FSCAL1 Frequency Synthesizer Calibration
0x1F, // FSCAL0 Frequency Synthesizer Calibration
0, // not used
0, // not used
0x59, // RESERVED_0X29 Use setting from SmartRF Studio
0x7F, // RESERVED_0X2A Use setting from SmartRF Studio
0x3F, // RESERVED_0X2B Use setting from SmartRF Studio
0x81, // TEST2 Various Test Settings
0x35, // TEST1 Various Test Settings
0x09, // TEST0 Various Test Settings
0xC0 // PATABLE +10dbm



  • Hi Sasuke,

    The unexpected transitions on GDO2 can easily be caused by other radio devices operating in the vicinity. Have you tried connecting an antenna directly to a spectrum analyzer and see if it picks up anything?

    Even though you change the channel of your transmitter, some power will still leak into the adjacent channels.


  • Hi Fredrik K

                       Thanks for your response sir.

    1>Yes i have assured using spectrum analyzer and i don't see any radio signal near in vicinty. [when i change the AGCCTRL0 value from 91 to B0 unexpected transitions get reduced very much can u please explain why?]

    2> If it is going to leak some power in adjacent channels then how to find whether my channel is clear or not and how to implement CCA?

    Is there something wrong with my register settings related to CCA implementation can you please provide some working setting? 

    Thanks :)