CC2640R2F: central get RSSI of advertising data,RSSI value is very unstable

weimin ren

Part Number: CC2640R2F

Hi,

I get RSSI periodly with 2640R2F based on simple central example. The distance between central and advertising device is fixed.

Rssi changes very frequently,range could be larger than 15dB.

At the same time, Rssi monitored on mobilephone is stable.

What may be the.root cause? Thanks

over 6 years ago

0 J Lindh over 6 years ago

TI__Guru 57865 points

Hi,
Are you testing in a very noisy environment?

0 Eirik V over 6 years ago

TI__Guru 56590 points

Hello Weimin,
The RSSI value on the smartphone might be averaged/filtered. You could add some basic averaging or filtering to get a more stable result. Or find an large open area with low interference (e.g. large open field).

Are they connected or are you scanning advertisements?

In a connection The RSSI value will be based on the last connection event transfer which means the effective connection interval will be equivalent to the internal RSSI value update.

0 weimin ren over 6 years ago in reply to Eirik V

Intellectual 270 points

i'm scanning advertisement. scan interval is 200ms.

is there any receive gain setting that improves stability? thanks

0 weimin ren over 6 years ago in reply to J Lindh

Intellectual 270 points

i tested in office, maybe some pepole walk around. but the value changes very quickly.

0 Eirik V over 6 years ago in reply to weimin ren

TI__Guru 56590 points

What is the advertisement interval?
If you set scan window equal to scan interval the scanner will only scan on a single channel for every interval before changing to the next advertisement channel 37->38->39.
Have you gone through the Bluetooth Low Energy Scanning and Advertising training lab? I can highly recommend learn more about it:
dev.ti.com/.../