esp32

name	esp32
description	ESP32 programming: Wi-Fi/BLE integration, GPIO muxing, FreeRTOS tasks, and power management.

esp32

Goal: Develop embedded applications on ESP32 MCUs, utilizing its dual-core CPU, Wi-Fi/BLE radios, and advanced peripheral matrix.

1. Hardware Overview

• Voltage: 3.3V Logic.
• ADC: Dual 12-bit ADCs, but ADC2 cannot be used while Wi-Fi is active.
• Strapping Pins: Pins 0, 2, 5, 12, 15 must be at specific logic levels during boot. Avoid using them for inputs if possible.
• Muxing: Almost any GPIO can be assigned to hardware I2C, SPI, or UART using the ESP32 matrix.

2. Radio & Network (Arduino Core)

#include <WiFi.h>

void setup() {
  WiFi.mode(WIFI_STA);
  WiFi.begin("SSID", "PASSWORD");
  while (WiFi.status() != WL_CONNECTED) { delay(500); }
}

3. FreeRTOS Tasks

ESP32 runs FreeRTOS by default. Avoid blocking loop(); instead, spawn isolated tasks (especially to pin 0 vs pin 1).

void myTask(void * parameter) {
  for(;;) {
    // Task logic
    vTaskDelay(100 / portTICK_PERIOD_MS); 
  }
}

void setup() {
  xTaskCreatePinnedToCore(
    myTask,   /* Function to implement the task */
    "Task1",  /* Name of the task */
    10000,    /* Stack size in words */
    NULL,     /* Task input parameter */
    1,        /* Priority of the task */
    NULL,     /* Task handle */
    0);       /* Core where the task should run */
}

4. OPSEC & Deployments

• Avoid writing raw credentials to flash without NVS encryption if physical extraction is a threat.
• Deep Sleep reduces draw to ~10µA. Wake via RTC GPIO or Timer.