# Install esptool
pip install esptool

# Find your port
# Linux:   ls /dev/ttyUSB*
# Mac:     ls /dev/cu.*
# Windows: Device Manager -> Ports

# 1. Erase the flash completely
esptool.py --port /dev/ttyUSB0 erase_flash

# 2. Download firmware for your chip:
#    https://micropython.org/download/
#    Choose ESP32 / ESP32-S3 / ESP32-C3 as appropriate

# 3. Flash (original ESP32 -- offset 0x1000)
esptool.py --chip esp32 --port /dev/ttyUSB0 --baud 460800 \
  write_flash -z 0x1000 esp32-vX.X.X.bin

# 4. Flash (S2, S3, C3 -- offset 0x0)
esptool.py --chip esp32s3 --port /dev/ttyUSB0 --baud 460800 \
  write_flash -z 0x0 ESP32_GENERIC_S3-vX.X.X.bin

# 5. Connect: Thonny auto-detects, or serial at 115200 baud

import network, time

SSID     = 'YourSSID'
PASSWORD = 'YourPassword'

def connect_wifi():
    wlan = network.WLAN(network.STA_IF)
    wlan.active(True)
    if wlan.isconnected():
        return wlan.ifconfig()[0]
    wlan.connect(SSID, PASSWORD)
    timeout = 15
    while not wlan.isconnected() and timeout > 0:
        print('.', end='')
        time.sleep(1)
        timeout -= 1
    if wlan.isconnected():
        ip = wlan.ifconfig()[0]
        print(f'\nConnected: {ip}')
        return ip
    print('\nFailed to connect')
    return None

# Access Point mode (create your own network)
def start_ap(ssid='ESP32-AP', pwd='12345678'):
    ap = network.WLAN(network.AP_IF)
    ap.active(True)
    ap.config(essid=ssid, password=pwd, authmode=3)
    print('AP IP:', ap.ifconfig()[0])

1. File -> Preferences -> Additional Boards Manager URLs:
   https://raw.githubusercontent.com/espressif/arduino-esp32/gh-pages/package_esp32_index.json

2. Tools -> Board -> Boards Manager -> search 'esp32'
   Install: esp32 by Espressif Systems (v3.x recommended)

3. Select your board:
   Tools -> Board -> ESP32 Arduino -> [your board]
   Common: ESP32 Dev Module, LOLIN D32, ESP32-S3 Dev Module

4. Upload settings:
   Tools -> Upload Speed -> 921600
   Tools -> Port -> your port

5. Hold BOOT button during upload if upload fails

6. Monitor: Tools -> Serial Monitor -> 115200 baud

// Basic I/O
const int LED = 2;   // On-board LED on most ESP32 DevKit boards
const int BTN = 0;   // BOOT button

void setup() {
  Serial.begin(115200);
  pinMode(LED, OUTPUT);
  pinMode(BTN, INPUT_PULLUP);
}
void loop() {
  digitalWrite(LED, !digitalRead(BTN));
}

// Analogue read (12-bit: 0-4095)
int val   = analogRead(34);         // ADC1 pin -- safe with WiFi
float v   = val * 3.3f / 4095.0f;

// PWM using LEDC (replaces analogWrite on ESP32)
const int FREQ    = 5000;
const int CHAN    = 0;
const int RES     = 8;   // 8-bit: 0-255
ledcSetup(CHAN, FREQ, RES);
ledcAttachPin(LED, CHAN);
ledcWrite(CHAN, 128);    // 50% duty cycle

// Interrupt on falling edge
void IRAM_ATTR handleIRQ() { /* keep very short */ }
attachInterrupt(BTN, handleIRQ, FALLING);