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Nothing on this page is a scripted animation: the firmware is compiled and executed, and the circuit around it is solved.
arduino-cli compiles it, an AVR8 core executes it instruction by instruction, and the LCD shows what the ATmega328P actually put on the bus. Uno, Nano, Mega and ATtiny85, no board on your desk.

arduino-cli or ESP-IDF compiles the sketch, then AVR8, RP2040, RISC-V, Xtensa or ARM executes it instruction by instruction. What the OLED draws and what the serial monitor prints is what the chip actually did.

ngspice compiled to WebAssembly runs a full nodal analysis about 60 times a second. GPIO pins drive real nets, ADC inputs read solved node voltages, and probes report RMS, DC and current wherever you drop them.

Adders, comparators, decoders, flip-flops and a 1-bit ALU slice: no microcontroller anywhere, just gates, switches and LEDs solved as a real net. The classroom half of electronics, without the breadboard.

The M5Stack Cardputer with its keyboard, Seeed's round display keeping time, Pimoroni's Badger 2350 driving e-paper, and DFRobot's UNIHIKER M10 in the catalogue alongside them. Their makers sent the hardware so the emulation could be checked against the real thing.




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An interactive Xiao Esp32S3 Sense circuit simulation you can run free in your browser on Velxio, by buduojun.
/**
* XIAO ESP32S3 Sense — SSD1306 128×64 OLED (I2C, 4-pin)
*
* 接线 (4-pin OLED → XIAO ESP32S3 Sense):
* OLED VCC → 3V3 (3.3V)
* OLED GND → GND
* OLED SCL → D5 (GPIO7)
* OLED SDA → D4 (GPIO6)
*
* 依赖库 (通过 Arduino Library Manager 安装):
* - Adafruit GFX Library
* - Adafruit SSD1306
*
* 注意:
* - XIAO ESP32S3 的默认 I2C 引脚不是 21/22,必须显式指定
* - 如果使用其他引脚,修改 Wire.begin(sda, scl) 的参数即可
*/
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
// ─── 显示屏参数 ───
#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
#define OLED_RESET -1 // 无复位引脚(4-pin OLED)
// ─── I2C 引脚定义(XIAO ESP32S3 Sense) ───
#define PIN_SDA 6 // D4
#define PIN_SCL 7 // D5
// ─── I2C 地址 ───
#define OLED_ADDR 0x3C // SSD1306 默认 I2C 地址
// ─── 创建显示对象 ───
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);
// ─── 计数器 ───
static int counter = 0;
// ============================================================
// setup()
// ============================================================
void setup() {
Serial.begin(115200);
delay(500); // 等待串口就绪
Serial.println("=== XIAO ESP32S3 Sense + SSD1306 OLED ===");
// ── 初始化 I2C(必须显式指定引脚) ──
Wire.begin(PIN_SDA, PIN_SCL);
// ── 初始化 SSD1306 ──
// SSD1306_SWITCHCAPVCC : 内部 3.3V 升压(仅需 3.3V 供电,最常用)
// SSD1306_EXTERNALVCC : 外部供电(需额外 7~9V 电源)
if (!display.begin(SSD1306_SWITCHCAPVCC, OLED_ADDR)) {
Serial.println("[ERROR] SSD1306 未找到!请检查接线和 I2C 地址。");
while (true) delay(10); // 卡住,等待复位
}
Serial.println("[OK] SSD1306 初始化成功");
// ── 初始显示 ──
display.clearDisplay();
display.setTextSize(2);
display.setTextColor(SSD1306_WHITE);
display.setCursor(8, 8);
display.println("Hello");
display.setCursor(8, 28);
display.println("XIAO!");
display.display();
delay(1500);
Serial.println("[READY] OLED 就绪,开始运行");
}
// ============================================================
// loop()
// ============================================================
void loop() {
counter++;
// ── 清屏并显示静态文本 ──
display.clearDisplay();
display.setTextSize(2);
display.setTextColor(SSD1306_WHITE);
display.setCursor(8, 4);
display.println("Hello");
display.setCursor(8, 24);
display.println("XIAO!");
// ── 显示计数器 ──
display.setTextSize(1);
display.setCursor(8, 50);
display.print("Count: ");
display.print(counter);
// ── 刷新显示 ──
display.display();
// ── 串口输出 ──
Serial.print("Frame: ");
Serial.println(counter);
delay(1000);
}