CC1120EM-169-RD: get LQI value from CC1120

Nguyen Thanh Binh50

Part Number: CC1120EM-169-RD
Other Parts Discussed in Thread: CC1120

Support Path: /Tools & software/Help me with an issue/Design Kits / Evaluation Modules / Boards/Software issue/

Hello everyone, I am building a positioning system using CC1120 Evaluation Module Kit 169 Mhz. I want to get correct LQI values from CC1120's register, but it always return 0. If anybody who know how to fix this problem please help me, a sample code would be nice, thank you.

over 7 years ago

0 TER over 7 years ago

TI__Guru**** 317180 points

See e2e.ti.com/.../328402.

You should see other values than 0 when you are just above the sensitivity limit.

0 Nguyen Thanh Binh50 over 7 years ago in reply to TER

Prodigy 40 points

I have changed the distance between transmitter and receiver, then I received some other LQI values such as 1, 2, 3, 4... but I do not know how to verify whether it is a correct value

0 TER over 7 years ago in reply to Nguyen Thanh Binh50

TI__Guru**** 317180 points

Like I said in the thread I linked to: LQI is the distance to the ideal placement in the constellation diagram. A low number means close to a perfect link, when the LQI increases it starts to be difficult to receive the signal.

0 Nguyen Thanh Binh50 over 7 years ago in reply to TER

Prodigy 40 points

There is an error appears when I click on your link, so I can not see the thread which you mentioned

0 TER over 7 years ago in reply to Nguyen Thanh Binh50

TI__Guru**** 317180 points

e2e.ti.com/.../328402

Sometimes an extra character gets added to the URL when the link is generated making it invalid.

0 Nguyen Thanh Binh50 over 7 years ago in reply to Nguyen Thanh Binh50

Prodigy 40 points

I have read this thread, it's really helpful but I till face some other questions:
1. Could you let me know what the range of LQI values is? According to TI's document, 7 bits are used to represent a LQI value. In other words, LQI values change from 0 to 127, but when I increased the distance between transmitter and receiver from 0 meter to the position that the signal disappeared, I just received about 4 or 5 different LQI values.

2. I don't know whether LQI values of CC1120 and LQI values of other tranceivers have the same meaning?

0 TER over 7 years ago in reply to Nguyen Thanh Binh50

TI__Guru**** 317180 points

The meaning/ definition of LQI would most likely be different in different transceivers since the LQI will be dependent on the modem implementation.

You see the same as I have seen when I have checked the LQI on our measurement, the reported range is low.

Sub-1 GHz

Sub-1 GHz forum

CC1120EM-169-RD: get LQI value from CC1120