ESP32黄屏 万能IIC测试仪
资料（CN1一键扫描测试）

// ESP32-2432S028 / CYD 2.8 inch ST7789 internal LCD pins.
#define PIN_SCK  14
#define PIN_SDA  13
#define PIN_CS   15
#define PIN_RST  -1
#define PIN_DC   2
#define PIN_BLK  21

// CN1 sensor header: GND - IO22 - IO27 - 3V3. Any I2C device can go here.
#define I2C_SDA 27
#define I2C_SCL 22

// ESP32-2432S028R resistive touch controller, usually XPT2046.
#define TOUCH_CS   33
#define TOUCH_IRQ  36
#define TOUCH_MOSI 32
#define TOUCH_MISO 39
#define TOUCH_SCLK 25

// Standard I2C bus recovery: a device that got interrupted mid-byte can
// hold SDA low forever and jam the whole bus for every other device on it.
// Clocking SCL up to 9 times lets a stuck slave finish/release SDA, then a
// manual STOP condition puts the bus back to idle. Cheap to call any time
// (returns almost instantly) since it exits immediately once SDA is high.
static void recoverBus() {
  Wire.end();
  pinMode(I2C_SDA, INPUT_PULLUP);
  pinMode(I2C_SCL, OUTPUT);
  digitalWrite(I2C_SCL, HIGH);
  delayMicroseconds(5);
  for (uint8_t i = 0; i < 9 && !digitalRead(I2C_SDA); i++) {
    digitalWrite(I2C_SCL, LOW);
    delayMicroseconds(5);
    digitalWrite(I2C_SCL, HIGH);
    delayMicroseconds(5);
  }
  pinMode(I2C_SDA, OUTPUT);
  digitalWrite(I2C_SDA, LOW);
  delayMicroseconds(5);
  digitalWrite(I2C_SCL, LOW);
  delayMicroseconds(5);
  digitalWrite(I2C_SCL, HIGH);
  delayMicroseconds(5);
  digitalWrite(I2C_SDA, HIGH);
  delayMicroseconds(5);
  Wire.begin(I2C_SDA, I2C_SCL);
  Wire.setClock(100000);
  Wire.setTimeOut(8);
  delay(5);
}

// A freshly-mated connector can bounce, and a module mid power-on can
// glitch-ACK the wrong address for a few ms. Don't latch on the first
// hit alone: let it settle, then re-scan and only commit if the same
// address confirms. This is what "first read shows the wrong address,
// retesting fixes it" was — nothing wrong with the module, we were just
// reading before the bus/power had settled.
delay(30);
for (uint8_t addr = 1; addr < 127; addr++) {
  if (probeAddress(addr) == 0) {
    if (addr == candidate) {
      activeAddr = addr;
      return true;
    }
    return false;
  }
}
return false;

drawTextBg(12, 66, "TOF INIT", YELLOW, BLACK, 3);
// begin() uploads ~80KB of firmware into the sensor over I2C and can
// legitimately take several seconds — pull the loop task off the
// watchdog for just this one call so that doesn't look like a hang.
esp_task_wdt_delete(NULL);
bool tofOk = vl53l5cx.begin(VL53L5CX_ADDR, &Wire, 400000) &&
             vl53l5cx.setResolution(64) &&
             vl53l5cx.setRangingFrequency(15) &&
             vl53l5cx.startRanging();
esp_task_wdt_add(NULL);