LoRa initialization fails on two new Heltec WiFi LoRa 32 V3 (ESP32-S3) boards

[mtimos]

Hello,
I have two new Heltec WiFi LoRa 32 V3 (with ESP32-S3) boards. The LoRa radio fails to initialize (LoRa.begin() returns false) on both of them.

This happens even with the official library examples and with code using manual pin definitions for the V3 (SPI on GPIOs 9,10,11,8 and RST on 12, IRQ on 14). The board is correctly selected as "Heltec WiFi LoRa 32(V3)" in the Arduino IDE.

Is there a known issue with recent V3 board revisions or a required software update? Thank you.

UPDATE: I have confirmed the boards are the 433MHz version, as it is printed on the box. I tried to initialize the radio at 433E6 and LoRa.begin() still fails with the same error on both boards. This seems to be a fundamental incompatibility.

[UniquePete]

It looks to me like you are using the wrong LoRa library... A call to LoRa.begin() suggests that you are using the Sandeep Mistry library, or similar (LoRa.h). This library does not support the SX1262 LoRa chip on the WiFI LoRa 32 V3 and later boards. You need to be using something like the LoRaWan_APP or RadioLib libraries. You should check the Heltec forums for discussion on this subject.

If you are not sure whether you are dealing with a configuration issue or a genuine product failure, it's always a good idea to check the Heltec forums first.

[Ahmedchetoui]

Je trouve un probléme de Spi timeout pour une carte heltec lora wifi 32 v3.
Commment je resoudre ?
/* =====================================================
LORA SENSOR CARD - FIXED VERSION
Key fixes:
1. Added TxDone callback for proper TX->RX transition
2. Added state machine to prevent RX/TX conflicts
3. Synchronized sensor reading with data sending
4. Fixed display update timing
===================================================== */
#include "LoRaWan_APP.h"
#include "Arduino.h"
#include <DHT.h>
#include <Wire.h>
#include "HT_SSD1306Wire.h"
// ---- OLED ----
static SSD1306Wire display(0x3c, 500000, SDA_OLED, SCL_OLED,
GEOMETRY_128_64, RST_OLED);
// ---- DHT Configuration ----
#define DHTPIN 33
#define DHTTYPE DHT22
DHT dht(DHTPIN, DHTTYPE);
// ---- MQ-135 (Gaz) ----
#define MQ135_PIN 35
// ---- LED Control ----
#define LED_PIN 12
// ---- LORA CONFIG ----
#define RF_FREQUENCY 915000000
#define LORA_BW 0
#define LORA_SF 7
#define LORA_CR 1
#define LORA_PREAMBLE 8
char rxpacket[150];
int16_t rssi, rxSize;
static RadioEvents_t RadioEvents;
// ---- NEW: State machine ----
enum RadioState {
STATE_RX,
STATE_TX,
STATE_SWITCHING
};
RadioState radioState = STATE_RX;
unsigned long txStartTime = 0;
const unsigned long TX_TIMEOUT = 2000; // 2 second timeout for TX
// ---- Variables d'état ----
float temperature = 0;
float humidity = 0;
int gasLevel = 0;
String ledState = "OFF";
unsigned long lastDisplayUpdate = 0;
bool showingCommand = false;
// ---- Timers ----
unsigned long lastDataSent = 0;
const unsigned long SEND_INTERVAL = 10000; // Envoyer toutes les 10s
// ---- Fonction : Lire les capteurs ----
void readSensors() {
// Lire température et humidité
temperature = dht.readTemperature();
humidity = dht.readHumidity();

// Gérer les erreurs DHT
if (isnan(temperature) || isnan(humidity)) {
Serial.println("❌ Erreur lecture DHT22");
temperature = 0;
humidity = 0;
} else {
Serial.printf("✅ DHT22 : T=%.1f°C, H=%.1f%%\n", temperature, humidity);
}

// Lire niveau de gaz (MQ-135)
int rawGas = analogRead(MQ135_PIN);
gasLevel = map(rawGas, 0, 4095, 0, 200);
Serial.printf("✅ MQ-135 : Gas=%d (raw=%d)\n", gasLevel, rawGas);
}
// ---- Fonction : Afficher sur OLED ----
void updateDisplay() {
display.clear();
display.setFont(ArialMT_Plain_10);

display.drawString(0, 0, "Card 1 - Sensor");
display.drawString(0, 10, "--------------------");
display.drawString(0, 22, "T: " + String(temperature, 1) + " C");
display.drawString(0, 34, "H: " + String(humidity, 1) + " %");
display.drawString(0, 46, "G: " + String(gasLevel));
display.drawString(0, 56, "LED: " + ledState + (ledState == "ON" ? " 🔴" : " ⚫"));

display.display();
}
// ---- NEW: Fonction pour afficher message de commande ----
void showCommandMessage(String cmd) {
display.clear();
display.setFont(ArialMT_Plain_10);
display.drawString(0, 20, "Command Received:");
display.drawString(0, 35, cmd);
display.display();
showingCommand = true;
lastDisplayUpdate = millis();
}
// ---- Fonction : Envoyer les données via LoRa ----
void sendData() {
// Check if radio is stuck in TX mode for too long
if (radioState == STATE_TX && (millis() - txStartTime > TX_TIMEOUT)) {
Serial.println("⚠️ TX timeout! Forcing back to RX mode");
Radio.Rx(0);
radioState = STATE_RX;
}

if (radioState != STATE_RX) {
Serial.println("⚠️ Radio occupée, envoi ignoré");
return;
}

// Formater le message au format compact (plus efficace)
char buffer[150];
snprintf(buffer, sizeof(buffer),
"T=%.1f H=%.1f G=%d LED=%s",
temperature, humidity, gasLevel, ledState.c_str());

Serial.println("📤 Envoi LoRa:");
Serial.println(buffer);

radioState = STATE_TX;
txStartTime = millis(); // Record when TX started
Radio.Send((uint8_t*)buffer, strlen(buffer));
}
// ---- Setup ----
void setup() {
Serial.begin(115200);
Mcu.begin(HELTEC_BOARD, SLOW_CLK_TPYE);
// ---- Initialiser OLED ----
pinMode(Vext, OUTPUT);
digitalWrite(Vext, LOW);
delay(100);
display.init();
display.setTextAlignment(TEXT_ALIGN_LEFT);
display.clear();
display.setFont(ArialMT_Plain_10);
display.drawString(0, 0, "Card 1 Init...");
display.display();
// ---- Initialiser DHT22 ----
Serial.println("🌡 Initialisation DHT22...");
dht.begin();
// ---- Initialiser LED ----
pinMode(LED_PIN, OUTPUT);
digitalWrite(LED_PIN, LOW);
Serial.println("💡 LED initialisée (OFF)");
// ---- Initialiser LoRa ----
Serial.println("📡 Initialisation LoRa...");

// ===== CRITICAL: Hard reset LoRa radio (fixes V3 SPI timeout on re-upload) =====
pinMode(RST_LoRa, OUTPUT);
digitalWrite(RST_LoRa, LOW);
delay(10);
digitalWrite(RST_LoRa, HIGH);
delay(100);
Serial.println("🔄 LoRa radio reset");
// ===== RX Done - Réception de commandes =====
RadioEvents.RxDone = [](uint8_t *payload, uint16_t size, int16_t rssi_val, int8_t snr) {
rssi = rssi_val;
rxSize = size;
memcpy(rxpacket, payload, size);
rxpacket[size] = '\0';

Serial.println("\n📥 LoRa REÇU:");
Serial.println(rxpacket);
Serial.printf("RSSI: %d dBm\n", rssi);

// Vérifier si c'est une COMMANDE LED
String cmd = String(rxpacket);

if (cmd.indexOf("CMD:LED") >= 0) {
  // Afficher le message reçu
  showCommandMessage(cmd);
  
  // Traiter la commande
  String cmdUpper = cmd;
  cmdUpper.toUpperCase();
  
  if (cmdUpper.indexOf("ON") >= 0 && cmdUpper.indexOf("OFF") < 0) {
    ledState = "ON";
    digitalWrite(LED_PIN, HIGH);
    Serial.println("🔴 LED ALLUMÉE (commande ON reçue)");
  } else if (cmdUpper.indexOf("OFF") >= 0) {
    ledState = "OFF";
    digitalWrite(LED_PIN, LOW);
    Serial.println("⚫ LED ÉTEINTE (commande OFF reçue)");
  }
} else {
  // Message de données d'un autre device - ignorer
  Serial.println("ℹ Message de données reçu, ignoré");
}

// Rester en mode RX
radioState = STATE_RX;

};
// ===== NEW: TX Done - Transmission terminée =====
RadioEvents.TxDone = {
Serial.println("✅ Transmission LoRa terminée");
radioState = STATE_SWITCHING;

// Retourner en mode réception
delay(200);
Radio.Rx(0);
radioState = STATE_RX;
Serial.println("📶 Retour en mode réception");

};
// ===== NEW: TX Timeout =====
RadioEvents.TxTimeout = {
Serial.println("❌ Timeout transmission LoRa");
radioState = STATE_SWITCHING;
Radio.Rx(0);
radioState = STATE_RX;
};
Radio.Init(&RadioEvents);
Radio.SetChannel(RF_FREQUENCY);
// Configuration RÉCEPTION
Radio.SetRxConfig(
MODEM_LORA, LORA_BW, LORA_SF, LORA_CR,
0, LORA_PREAMBLE, 0, false, 0, true, 0, 0, false, true
);
// ===== NEW: Configuration TRANSMISSION =====
Radio.SetTxConfig(
MODEM_LORA, 14, 0, LORA_BW, LORA_SF, LORA_CR,
LORA_PREAMBLE, false, true, 0, 0, false, 3000
);
// Démarrer la réception
Radio.Rx(0);
radioState = STATE_RX;

Serial.println("✅ Capteur prêt - En attente de commandes LoRa...\n");

// Lire les capteurs au démarrage
readSensors();
updateDisplay();
}
// ---- Loop ----
void loop() {
Radio.IrqProcess();
// ---- Watchdog: Check if radio is stuck in TX mode ----
if (radioState == STATE_TX && (millis() - txStartTime > TX_TIMEOUT)) {
Serial.println("🔧 Watchdog: TX stuck! Forcing RX mode");
Radio.Rx(0);
radioState = STATE_RX;
}
// ---- Envoyer les données toutes les 10s ----
if (millis() - lastDataSent > SEND_INTERVAL) {
lastDataSent = millis();

// Lire les capteurs AVANT d'envoyer (données fraîches)
readSensors();

// Envoyer les données
sendData();

}
// ---- Mettre à jour l'affichage OLED ----
// Si on affiche un message de commande, attendre 2s avant de revenir à l'affichage normal
if (showingCommand && (millis() - lastDisplayUpdate > 2000)) {
showingCommand = false;
updateDisplay();
} else if (!showingCommand && (millis() - lastDisplayUpdate > 1000)) {
// Mettre à jour l'affichage normal toutes les 1s
lastDisplayUpdate = millis();
updateDisplay();
}
delay(10);
}