CC1101: RSSI Not changing when I transmit from my other device

Tony Pitman

Part Number: CC1101

Tool/software:

I am trying to detect a 433mhz signal from a tpms sensor.

I am setting the cc1101 to direct mode because I want to process all of the raw signals in software on my MCU.

I can see a ton of pulses coming via the gpo0 pin on the cc1101 to my MCU. I am sure most of it is noise, so I need to use the RSSI to detect when my signal is being sent.

I can see on my log output the RSSI value and it is always about 0xA5.

This doesn't change when I know I am sending a signal from the tpms sensor. I have another app running on my PC that shows the tpms sensor data so I know it is actually sending something.

The device is withint 12 inches of the cc1101 antenna.

Can I get RSSI in raw direct mode or do I have to set up some kind of packet settings on the cc1101?

5 months ago

0 TheGhostOf 5 months ago

Mastermind 6470 points

You should get the RSSI with the way you have implemented it. But even if you only receive noise, the RSII level should have at least 10 dB variation.

You should check if the CC1101 is in saturation: www.ti.com/.../swra147b.pdf

You should check if you have a frequency offset between your RX and RX device.

0 Alex Fager 5 months ago

TI__Genius 12441 points

Hello,

Currently the sub-1 experts are out of office. Once they return, they will respond to your question.

Thanks,
Alex F

0 Tony Pitman 5 months ago in reply to Alex Fager

Prodigy 50 points

Thank you for the reply. I look forward to their response.

0 Arthur R☑️ 5 months ago in reply to Tony Pitman

TI__Mastermind 25315 points

Hi Tony,

As TheGhostOf stated, have you checked that the CC1101 is saturating? According to the same application that was linked.

Regards,

Arthur

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CC1101: RSSI Not changing when I transmit from my other device