CC113L: Unstable reception issue

user5901162

Prodigy 65 points

Part Number: CC113L
Other Parts Discussed in Thread: CC115L,

Hello.

Base Frequency : 433.92MHz,

Xtal Freq. : 26MHz

Data rate : 8.4KBaud

RX filter BW : 135HHz,

Modulation : OOK

phenomenon : RSSI(dBm) / PER(%)

@CC113LDK_EM_433 @My board

-83.2 / 0 -83.8 / 0

-84.9 / 0 -84.9 / 0

-87.0 / 0 -86.9 / 0

-88.4 / 0 -87.9 / 1

-90.5 / 0 -90.1 / 11

-92.6 / 0 -92.6 / 31

-93.8 / 0 -93.8 / 42

-96.0 / 0 -95.8 / 38

-97.7 / 0 -97.7 / 35

-99.2 / 0 -99.4 / 54

-101.0 / 8 -100.7 / 33

-102.1 / 85 -102.0 / 98

-103.x / 100 -103.x / 100

How can I improve this unstability?

Thank you in advance.

over 6 years ago

0 TER over 6 years ago

TI__Guru**** 317180 points

It looks like your board has > 10 dB porrer sensitivity that the EM.

Are the measurements done equally on both boards and are these conducted measurements? If the measurements are done equal and with the same settings, I suspect a hardware issue.

I can do a quick review or your schematic and layout if you like (send me a friend request with the files, pdf, gerber)

0 user5901162 over 6 years ago in reply to TER

Prodigy 65 points

Hello,

Thank you for your kind reply.

Both boards are tested in almost same condition and exactly same register setting.
Tested in shield box through air.

0 TER over 6 years ago in reply to user5901162

TI__Guru**** 317180 points

I have accepted you friend request request

0 user5901162 over 6 years ago in reply to TER

Prodigy 65 points

Thank you.
The schematic is the same as the datasheet's recommended circuit schematic and uses a helical antenna.

0 TER over 6 years ago in reply to user5901162

TI__Guru**** 317180 points

Please send me the schematic and layout as private message since it's clearly a difference between the boards based on the sensitivity measurements.

0 TER over 6 years ago in reply to TER

TI__Guru**** 317180 points

Your grounding is not ideal since the decoupling gets a longer way back to chip ground.

I also not that you use a fairly large load caps for the xtal, what is the Cload spec for this xtal?

A poor layout will normally just shift the threshold you see on the EM to a higher value. A transition from 0 % PER to 100 % PER will normally be just a 2- 3 dB wide as on the EM. A longer transition will normally be caused by poor settings. A second reason could be frequency offset. Have you checked which frequency you exactly you send on?

0 user5901162 over 6 years ago in reply to TER

Prodigy 65 points

Thank you for your opinion.
I will some photo of my test circumstance and register settings by private message.
Tx by CC115L (Evaluation board with CC115L (433MHz) EM module)
Rx CC113L (My board controlled by Evaluation board)

0 TER over 6 years ago in reply to user5901162

TI__Guru**** 317180 points

The extra information I received don't give me any real new information.

I assume both the EM and your custom board uses the same settings?

- Have you checked the frequency offset for your board
- Test conducted

0 user5901162 over 6 years ago in reply to TER

Prodigy 65 points

Yes, both boards are tested at same settings.
How do I check the frequency offset?
- Test conducted? <- I can not understand what this means?
Thank you.

0 user5901162 over 6 years ago in reply to TER

Prodigy 65 points

Thank you so much.

I solved the problem by enhance the ground path as your opinion.

I once again confirmed the importance of ground.

Thank you again. :)

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CC113L: Unstable reception issue