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CC113L: Keeloq receiver low range

Denis Mascarell
Prodigy 10 points
Part Number: CC113L
Other Parts Discussed in Thread: TEST2

Tool/software:

I'm using the CC113L with an own prototipe as a Keelog receiver for 868.35 MHz band. Following the design note DN022, a  post in the forum about receiver for keelog and the Applications, Implementation, and Layout section of the datasheet, I find myself with a receiver working for a range of less than 10 meters. 

I have tried to increase the range modifying the registers but nothing seems to work, increasing the sensibility only makes the signal disappear in noise. I have tried playing with the AGCCTRL registers, the Data Rate 

 and BW, but the range doesn't get any better.  What configuration/change should i make in orfer to improve the range?

IOCFG0           0x0D
FIFOTHR         0x47
SYNC1             0xD3
SYNC0             0x91
PKTLEN           0xFF
PKTCTRL1       0x04 
PKTCTRL0       0x32
ADDR               0x00
CHANNR          0x00  
FSCTRL1         0x06
FSCTRL0         0x00
FREQ2             0x21
FREQ1             0x65
FREQ0             0xE8
MDMCFG4       0x77
MDMCFG3       0x32
MDMCFG2       0x30
MDMCFG1       0x02
MDMCFG0       0xF8
DEVIATN          0x15
MCSM2            0x07
MCSM1            0x30
MCSM0            0x18
FOCCFG          0x14
BSCFG             0x6C
AGCCTRL2      0x03
AGCCTRL1      0x00
AGCCTRL0      0x92
FREND1           0xB6
FSCAL3            0xE9
FSCAL2            0x2A
FSCAL1            0x00
FSCAL0            0x1F
TEST2              0x81
TEST1              0x35
TEST0              0x09

  • 0
    TI__Mastermind 18065 points

    Hi,

    • What HW are you using?
    • If you test the range using a default PHY setting (e.g. GFSK) and SmartRF Studio 7, does the range issue persist or is it specific to these PHY settings?

    Regards,

    Zack

  • 0 in reply to ZC
    Mastermind 6470 points

    Please take a look at www.ti.com/.../swra603a.pdf

  • 0 in reply to ZC
    Prodigy 10 points

    Hi Zack,

    ZC said:
    What HW are you using?

    I'm using a custom HW, the radio desing nonetheless is as per recomended in the datasheet with the same component values. The antenna I'm using is a semi-rigid cable.

    ZC said:
    If you test the range using a default PHY setting (e.g. GFSK) and SmartRF Studio 7, does the range issue persist or is it specific to these PHY settings?

    The same HW for GFSK works fine with a range of 50 meter.

    Best regards,

    Denis

  • 0 in reply to TheGhostOf
    Prodigy 10 points

    The sensitivity measures are poor (wireless and wired). I'm using the recommended HW and the configuration of the SmartRF Studio 7. Since the same HW works for GFSK i guess that there is something with the configurations.

  • 0 in reply to Denis Mascarell
    TI__Mastermind 18065 points

    Hi Denis,

    Apologies for the delay on this. I have unlocked the thread and aim to reply early next week. I need feedback from the design team for how to progress this.

    From what you say (good performance with GFSK), it does sound like a configuration issue rather than a HW issue, but are you able to confirm this with conducted measurements as outlined in SWRA603? That makes it easier to quantify the performance in a way that is repeatable.

    Regards,

    Zack

  • 0 in reply to ZC
    Prodigy 10 points

    Hi Zack,

    Glad to know about you. The measures conducted are following the SWRA603 using a signal generator sending preamble data. The signal is visible at -32 dBm. Since the HW is the one recommended in the datasheet I also think that it is related to the configuration, but I don't find the register that make it work.

    Best regards,

    Denis

  • 0 in reply to Denis Mascarell
    TI__Mastermind 18065 points

    Hi Denis,

    Regarding the Keeloq protocol: is this OOK with a different bit time duration for logic 1s and 0s? The context for the question is that I am trying to find an engineer who may have previously worked on this. 

    Regards,

    Zack

  • 0 in reply to ZC
    Prodigy 10 points

    Hi Zack, 

    Is as you say OOK modulation with different bit time duration.

    Best regards, 

    Denis

  • 0 in reply to Denis Mascarell
    TI__Mastermind 18065 points

    I think I've found a colleague who has supported this before, but we're still trying to see if we have data we can share (as it was so long ago).

    From another colleague, the following information may help if you can provide it (but it's not guaranteed we're talking about the same PHY):

    What is the shortest bit duration? (200 us?) Seem to recall that logic 1 is 2x logic 0 (but could be wrong). The "trick" is to use a data (symbol) rate that matches the shortest bit duration. The other bit will then be two symbols long. The sync word also need to account for this. 

    Regards,

    Zack

  • 0 in reply to ZC
    Prodigy 10 points

    Hi Zack,

    The basic pulse element is about 260 us minimum. For my case the logic for 0 is 2x logic 1.

    If i'm not misstaken the configuration i use in MDMCFG4 (low) and MDMCFG3 for the data rate should be for a 3.8 kbaud, which translates to a 260 us. I also tried with other data rates and didn't seem to improve the range.

    Best regards,

    Denis Mascarell