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Generic 433 / 868 MHz transceiver

Johan Gustafsson1
Prodigy 35 points
Other Parts Discussed in Thread: CC1101, CC1310

Hi,

I would like to develop a generic 433 and 868 MHz receiver using only 2 ICs and 2 antennas. The receiver needs to be able to receive radio signals on a broad band (all of 433MHz and 868MHz band) with different modulations (FSK/OOK). This seems to have been accomplished before by Athom, ref below, by using just two CC1101 and one uC.

However, I cannot find anything about this in the datasheet of the CC1101. Could someone here please explain how this is accomplished?

Ref: blog.athom.com/.../

Kind regards

Johan

  • 0
    TI__Guru**** 317180 points
    Or you can do it with one IC using CC1310 single ended...

    Not sure exactly what you ask about. The blog you refer to seems to cover the how to fairly detailed.

    The CC1101 can operate both on the 433 MHz and 868 MHz band. If you look under www.ti.com/.../toolssoftware you will find reference designs for both frequency bands.

    The MCU has to have two SPI interfaces (or at least two lines that could act like CSn) to set up the two radios individually.
  • 0 in reply to TER
    Prodigy 35 points
    I know the specifications on CC1101, the different freqencies and the different modulations. It can communicate on 433 MHz, 868 MHz using FSK or OSK. My understanding is that one CC1101 can only communicate on one frequency using only one type of modulation.

    In this blog they detail how they merely use the CC1101 to receive the radio signals and intepret the bits on the uC. More often the CC1101 would handle the bits and radio packages on only one frequency (with different channels?). How would I use only one CC1101 to communicate with both 433.92 _and_ 433.42 MHz (without having to reprogram the CC1101 inbetween) as they describe in the blog?
  • 0 in reply to Johan Gustafsson1
    TI__Guru**** 317180 points
    It depends on how wide band your signals are I think.

    Maximum RX BW for CC1101 is 812.5 kHz. If you set the carrier frequency equal to 433.67 MHz you will be able to receive signals both on 433.92 MHz and 433.42 MHz. The penalty for making it very configurable is sensitivity.
  • 0 in reply to TER
    Prodigy 35 points

    Hi,

    Thanks for your time and answers! Ok, so with carrier frequency and wide BW it would be possible to receive on both channels. How would they proceed to receive both ASK and FSK (without changing the configuration of the transceiver)?

    They way I interpret the blog is that they receive the encoding on a interrupt-pin in the uC, and not decoding anything on the transceiver. Would it be possible to receive both ASK and FSK at the same time on CC1101?

    Johan