ESP32 + 2 CC1101 - send and receive simultaneously

[0x5c4r3]

Hey @jgromes ,
I am researching with your Library with the usual ESP32 and two CC1101.
I wrote a script to jam and receive at the same time with the two antennas, the configuration of the two CC1101 works perfectly and the jamming antenna too, the problem is the receiving one that outputs a code -6, ERR_RX_TIMEOUT.
Since the script is a bit long, maybe it is better if we quickly chat by email, I got some questions and I don't want to constantly write stuff in the github repo lol.

Also, what protocols does the library support? I am using a radio doorbell (433.92), trying to receive data from the CC1101 with the default script from your examples, but the signal is not detected and I keep receiving a code -6.

Thanks for your time!

[jgromes]

Feel free to ask here, that's what Discussions are about.

ERR_RX_TIMEOUT simply means there was nothing received during a call to the blocking CC1101::receive(). There's an interrupt-based version which is usually better, see CC1101_Receive_Interrupt.

Regarding the protocols that are supported, there's a couple ham radio protocols/digital modes, such as RTTY or AX.25. It's unlikely the doorbell uses using anything like that, my guess is it will be some simple FSK packet. You will have to record the signal with an SDR and examine it in order to determine the packet format and/or protocol.

[0x5c4r3]

I'll open an issue related to this discussion since seems ESP32 + CC1101 + RadioLib have some issues receiving the signal.
Thanks for the help for now!

[jgromes]

I got curious about this issue myself, and made a simple setup: Arduino Uno with CC1101 as the transmitter, and NodeMCU ESP32S with CC1101 as the receiver. I did indeed see some garbage packets, but not a lot of them, and they could always be easily distinguished by very high LQI and very low RSSI:

Valid packets: LQI < 8, RSSI > -50 dBm
Garbage packets: LQI >> 80, RSSI < -100 dBm

There might be some configuration issue that's making the receiver too sensitive, but that's most likely platform independent, so unrelated to ESP32 being used. Also I don't really have the time to search for this.

[0x5c4r3]

I see. What do you suggest to have it working? should I change board? and if so, which one do you suggest it's better to use two CC1101 at the same time?

[jgromes]

I'm not all that familiar with your project, was there a specific reason you decided to use CC1101? If not, SX1278 might be a better alternative.

[0x5c4r3]

Not really, I just need to send and receive from one device at the same time, the device and the antennas do not matter..
I see that the SX1278 manage only frequencies from 137.0 MHz to 525.0 MHz and I need to go a bit higher too..

Unfortunately, the only two boards I have here are the ESP32 and the Raspberry Pi Pico (not supported yet :/) so I will get an ESP8266s to double check if the problem is coming from the board or not.

[0x5c4r3]

So I kept digging, I found out that the working/not working of the antennas is quite random. Here's what's going on.
Code I run to set up the two CC1101:

...

CC1101 jammer = new Module(27, 17, RADIOLIB_NC, 26, SPI, SPISettings(2000000, MSBFIRST, SPI_MODE0));   
CC1101 control = new Module(13, 12, RADIOLIB_NC, 14, SPI, SPISettings(2000000, MSBFIRST, SPI_MODE0));

...


void begin() {
  int state1;
  int state2;
  while(1) {
    Serial.print("Configuring Jammer: ");
    SPI.begin();
    state1 = jammer.begin(frequency1, 32.0, 60.0, 250.0, 10, 32);
    if(state1 == ERR_NONE){
        Serial.print("DONE");Serial.println("");
        break;
    }
    else{
        Serial.print(state1);Serial.println(""); 
    }
  }
  while(state2 == ERR_NONE) {
    Serial.println("Configuring Control: ");
    SPI.begin();
    state2 = control.begin(frequency2, 32.0, 60.0, 250.0, 10, 32);
    if(state1 == ERR_NONE){
      Serial.println("DONE");Serial.println("");
      break;
    }
  }
  
}

I call the begin() in the setup().
When I run it, if I run it for the first time, it works immediately. If I reset the ESP32 (with the button), it starts outputting error -16 or -2 (randomly), sometimes it stops and works after a while, other times it just keeps going with the -16/-2 without stopping.
I notice that every time I change the GDO0 pin rewiring, it works the first time, no errors. If i start resetting, same thing described above happens (-16/-2).

Any idea why or how to stabilise the thing?

EDIT: Also I am noticing that if I let it run while it gives errors and I wait some minutes before resetting through the button, it then works. I am exploding here, help me lol

[jgromes]

Couple of thoughts:

1. Try enabling debug mode, it should give you some more insight into the -16 error codes (which is an SPI write fail).
2. You're continually initializing SPI in a loop, and I have no idea if ESP32 SPI driver is smart enough to handle this. The usual use-case is to initialize once on startup and then let it be.
3. Both error codes can also be related to hardware, which would explain the randomness. I just spent several weekends debugging an issue with Si4432, which turned out to be largely caused by a faulty breadboard, so I suggest thoroughly checking connections.

[0x5c4r3]

Other update: while I have the -2/-16 output going on, if I detach the 3V3 pin (power going from the ESP32 to the two antennas) from the board and reattach it back, errors stop and the setup finishes successfully.

(I'll keep the thread updated so if anyone else has the same problem he/she can follow my path.)

[jgromes]

What are you using as the power source? The 3.3V regulator on your ESP32 probably can't output enough current for the ESP32 as well as two CC1101 radios.

[0x5c4r3]

Yes, I disconnected the screen I was using and I think I solved the problem (I am a dumbass, I am powering the thing using a USB cable through a usb hub where I have my keyboard connected, prolly not enough power to handle all of that!)

I'll keep going, the antennas are now working quite well, thanks for the help for now, but I do know that I will find some other issue in the path I might need you for.

Thanks Jan, appreciate your work here.