Open
Description
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.