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CC1310: CC1310 Re-shape RF ramp up for higher data rates

David Wells58
Prodigy 150 points
Part Number: CC1310

Hi,

 

I am using a pair of RF-06 development boards and using software based on the rfPacketErrorRate example. I am transferring data from one board to the other with the following parameters:

Freq = 868MHz,

Bit rate = 500Kbps,

Prescale = 15,

Symbol rate word = 327680,

Modulation deviation = 250 KHz

 

The problem I’m seeing is that the power ramp-up is relatively slow at this rate and is consuming a large part of the preamble resulting in occasional missed packets. I have tried using SmartRF Studio v7 but the code output for smartrf_settings_predefined.c is essentially the same as I already have.

I have tried manually tweaking this register (in pOverrides[]):

// override_phy_gfsk_pa_ramp_agc_reflevel_0x1a.xml
// Tx: Enable PA ramping (0x41). Rx: Set AGC reference level to 0x1A.
HW_REG_OVERRIDE(0x6088,0x411A),

(second parameter to 0x431A and 0x441A) and it makes a huge improvement, but I can’t use that in a solution as I don’t know what I’m doing with it. I don’t see anything regarding this in the Technical Reference Manual. Can you give me any information on how to re-shape the ramp-up profile please?

 

  • 0
    TI__Genius 9705 points

    Hello David,

    PA ramping is configured in bits 15:8 of the value written at address 0x6088 (configured by the override). Bits 15:13 configure the PA trim time increment in steps of (8+4*2^PaTrimTime)/12 [us]. Bits 12:8 configure the the PA trim step size (zero is illegal, lower this value longer is the ramp time).

    In addition, ramp time can also be setup by changing the value for bits 15:8 at address 0x608C (default is HW_REG_OVERRIDE(0x608C,0x8213)). Bits 15:13 configure the PA ramp IB  time increment in steps of (8+4*2^PA ramp IB  time )/12 [us]. Bits 12:8 configure the the PA ramp IB step size (zero is illegal, lower this value, longer is the ramp time).

    Please refer to the following wiki for ramp settings used at higher data rates.

    http://processors.wiki.ti.com/index.php/Settings_for_Different_PHY%27s

    Regards,