ESP_NOW_Broadcast_Slave unable to handle more than 1 master

[faultylee]

Board

XIAO_ESP32C3

Device Description

Plain XIAO_ESP32C3

Hardware Configuration

WIFI
Serial
Built-in LED (GPIO 8)

Version

v3.0.7

IDE Name

Arduino IDE

Operating System

ArchLinux

Flash frequency

80

PSRAM enabled

yes

Upload speed

921600

Description

I adopted the example of libraries/ESP_NOW/examples/ESP_NOW_Broadcast_Slave/ESP_NOW_Broadcast_Slave.ino and proceed to setup 2 masters. It works fine with 1 master. Once the 2nd master started transmit and the slave registered it, it stop reacting to the first 1 master, as if nothing was received. I use the example as a push button remote control, and it's only transmitting one at a time when I was testing back and forth.

The master code is the same as the example except it transmit every 10ms continiously when the button is pressed.

I then found example online that uses the esp_now library directly instead of through ESP_NOW as per the example, and directly registering the callback using esp_now_register_recv_cb, then I was able to see messages from both the masters, while still using the same example code for master.

I couldn't figure out what went wrong in the slave example, but I suspect something within the vector or the peer registration that prevents the callback from working. Or that only 1 copy of ccallback is supported by esp_now?

Sketch

/*
    ESP-NOW Broadcast Slave
    Lucas Saavedra Vaz - 2024

    This sketch demonstrates how to receive broadcast messages from a master device using the ESP-NOW protocol.

    The master device will broadcast a message every 5 seconds to all devices within the network.

    The slave devices will receive the broadcasted messages. If they are not from a known master, they will be registered as a new master
    using a callback function.
*/

#include "ESP32_NOW.h"
#include "WiFi.h"

#include <esp_mac.h>  // For the MAC2STR and MACSTR macros

#include <vector>

/* Definitions */

#define ESPNOW_WIFI_CHANNEL 6
#define LED_BUILTIN 8

/* Global Variables */

bool is_triggered = false;

/* Classes */

// Creating a new class that inherits from the ESP_NOW_Peer class is required.

class ESP_NOW_Peer_Class : public ESP_NOW_Peer {
  public:
    // Constructor of the class
    ESP_NOW_Peer_Class(const uint8_t *mac_addr, uint8_t channel, wifi_interface_t iface, const uint8_t *lmk) : ESP_NOW_Peer(mac_addr, channel, iface, lmk) {}

    // Destructor of the class
    ~ESP_NOW_Peer_Class() {}

    // Function to register the master peer
    bool add_peer() {
      if (!add()) {
        log_e("Failed to register the broadcast peer");
        return false;
      }
      return true;
    }

    // Function to print the received messages from the master
    void onReceive(const uint8_t *data, size_t len, bool broadcast) {
      Serial.printf("Received a message from master " MACSTR " (%s)\n", MAC2STR(addr()), broadcast ? "broadcast" : "unicast");
      Serial.printf("  Message: %s\n", (char *)data);
      if (String((char *)data) == "Testing") {
        is_triggered = true;
      }
    }
};

// List of all the masters. It will be populated when a new master is registered
std::vector<ESP_NOW_Peer_Class> masters;


/* Callbacks */

// Callback called when an unknown peer sends a message
void register_new_master(const esp_now_recv_info_t *info, const uint8_t *data, int len, void *arg) {
  if (memcmp(info->des_addr, ESP_NOW.BROADCAST_ADDR, 6) == 0) {

    Serial.printf("Unknown peer " MACSTR " sent a broadcast message\n", MAC2STR(info->src_addr));
    Serial.println("Registering the peer as a master");

    ESP_NOW_Peer_Class new_master(info->src_addr, ESPNOW_WIFI_CHANNEL, WIFI_IF_STA, NULL);

    masters.push_back(new_master);
    if (!masters.back().add_peer()) {
      Serial.println("Failed to register the new master");
      return;
    }

  } else {
    // The slave will only receive broadcast messages
    log_v("Received a unicast message from " MACSTR, MAC2STR(info->src_addr));
    log_v("Igorning the message");
  }
}

/* Main */

void setup() {
  Serial.begin(115200);
  pinMode(LED_BUILTIN, OUTPUT);
  digitalWrite(LED_BUILTIN, HIGH);

  // Initialize the Wi-Fi module
  WiFi.mode(WIFI_STA);
  WiFi.setChannel(ESPNOW_WIFI_CHANNEL);
  while (!WiFi.STA.started()) {
    delay(100);
  }

  Serial.println("ESP-NOW Example - Broadcast Slave");
  Serial.println("Wi-Fi parameters:");
  Serial.println("  Mode: STA");
  Serial.println("  MAC Address: " + WiFi.macAddress());
  Serial.printf("  Channel: %d\n", ESPNOW_WIFI_CHANNEL);

  // Initialize the ESP-NOW protocol
  if (!ESP_NOW.begin()) {
    Serial.println("Failed to initialize ESP-NOW");
    Serial.println("Reeboting in 5 seconds...");
    delay(5000);
    ESP.restart();
  }

  // Register the new peer callback
  ESP_NOW.onNewPeer(register_new_master, NULL);

  Serial.println("Setup complete. Waiting for a master to broadcast a message...");
}

void loop() {
  if (is_triggered) {
    digitalWrite(LED_BUILTIN, LOW);
    is_triggered = false;
  } else {
    digitalWrite(LED_BUILTIN, HIGH);
  }
  delay(50);
}

Debug Message

09:09:43.042 -> ESP-NOW Example - Broadcast Slave

09:09:43.042 -> Wi-Fi parameters:

09:09:43.042 ->   Mode: STA

09:09:43.042 ->   MAC Address: 34:B7:DA:F8:14:50

09:09:43.042 ->   Channel: 6
09:09:43.042 -> Setup complete. Waiting for a master to broadcast a message...

09:09:48.415 -> Unknown peer f0:f5:bd:fd:96:a0 sent a broadcast message
09:09:48.415 -> Registering the peer as a master

09:09:48.415 -> Received a message from master f0:f5:bd:fd:96:a0 (broadcast)
09:09:48.415 ->   Message: Testing
09:09:48.415 -> Received a message from master f0:f5:bd:fd:96:a0 (broadcast)
09:09:48.415 ->   Message: Testing
09:09:48.448 -> Received a message from master f0:f5:bd:fd:96:a0 (broadcast)
09:09:48.448 ->   Message: Testing
09:09:48.448 -> Received a message from master f0:f5:bd:fd:96:a0 (broadcast)
09:09:48.448 ->   Message: Testing
09:09:48.448 -> Received a message from master f0:f5:bd:fd:96:a0 (broadcast)
09:09:48.448 ->   Message: Testing
09:09:48.482 -> Received a message from master f0:f5:bd:fd:96:a0 (broadcast)
09:09:48.482 ->   Message: Testing
09:09:50.605 -> Unknown peer 34:b7:da:f8:2c:f8 sent a broadcast message
09:09:50.605 -> Registering the peer as a master

09:09:50.605 -> Received a message from master 34:b7:da:f8:2c:f8 (broadcast)
09:09:50.605 ->   Message: Testing
09:09:50.638 -> Received a message from master 34:b7:da:f8:2c:f8 (broadcast)
09:09:50.638 ->   Message: Testing
09:09:50.638 -> Received a message from master 34:b7:da:f8:2c:f8 (broadcast)
09:09:50.638 ->   Message: Testing

NOTE: sending message from first master here and nothing show up

09:09:55.815 -> Received a message from master 34:b7:da:f8:2c:f8 (broadcast)
09:09:55.815 ->   Message: Testing
09:09:55.848 -> Received a message from master 34:b7:da:f8:2c:f8 (broadcast)
09:09:55.848 ->   Message: Testing
09:09:55.848 -> Received a message from master 34:b7:da:f8:2c:f8 (broadcast)
09:09:55.848 ->   Message: Testing
09:09:55.848 -> Received a message from master 34:b7:da:f8:2c:f8 (broadcast)
09:09:55.848 ->   Message: Testing

Other Steps to Reproduce

I have checked existing issues, online documentation and the Troubleshooting Guide

• I confirm I have checked existing issues, online documentation and Troubleshooting guide.