CC1310: Range Extender mode/ RSSI reading

Akshay Mishra

Part Number: CC1310
Other Parts Discussed in Thread: CC1190

Hello,

I have designed a board with an external RF Front End (Skyworks) with a typical gain of 16dB. I used it with SmartRF in two modes -- Configuring it as a regular CC1310 board and still enabling the GPIO for the Front End. With a transmitter kept within 1m range and transmitting at 14dBm (Launchpad) the RSSI in continuous RX is -15dBm.

However, if I change the module definition to a LaunchXL with Range Extender and then do the GPIO settings identical to above, the RSSI in continuous RX is -20dBm.

Is there an internal LNA which is turned-off when an external LNA is defined. What is the reason for the above behaviour.

Thanks,

Akshay

over 6 years ago

0 TER over 6 years ago

TI__Guru**** 317180 points

If you select "LaunchXL with Range Extender" the RSSI offset is adjusted compared to if you are using the default CC1310 settings. (See 2.3 in www.ti.com/.../swra542.pdf )

Since your design uses a different LNA than CC1190 you need to find the RSSI offset for your design by applying a signal you know the amplitude of and read out the RSSI. This has to be a conducted measurement.

0 Akshay Mishra over 6 years ago in reply to TER

Prodigy 160 points

Thanks,
We are using the SE2435L -- How do I change the offset value for this Front end. There is no reference available on calculating the offset value for the overrides.

0 TER over 6 years ago in reply to Akshay Mishra

TI__Guru**** 317180 points

Please see 2.3 in the app note I linked to in my last mail to see how you change RSSI offset. What you should change it to is a matter of testing with your frontend.

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CC1310: Range Extender mode/ RSSI reading