ESP32 读取 ULP 协处理器中的 DHT22 传感器

Question

我正在尝试在 ulp 深度睡眠中读取 dht22 传感器，但它无法正常工作，也许有人可以告诉我我做错了什么吗？

我正在重新实现 arduino-DHT 库，因为它使用我的传感器在非 ulp 模式下工作，它看起来像这样：

 digitalWrite(pin, LOW); // Send start signal
 pinMode(pin, OUTPUT);
 delayMicroseconds(800);

 pinMode(pin, INPUT);
 digitalWrite(pin, HIGH); // Switch bus to receive data

  // We're going to read 83 edges:
  // - First a FALLING, RISING, and FALLING edge for the start bit
  // - Then 40 bits: RISING and then a FALLING edge per bit
  // To keep our code simple, we accept any HIGH or LOW reading if it's max 85 usecs long

  uint16_t rawHumidity = 0;
  uint16_t rawTemperature = 0;
  uint16_t data = 0;

  for ( int8_t i = -3 ; i < 2 * 40; i++ ) {
    byte age;
    startTime = micros();

    do {
      age = (unsigned long)(micros() - startTime);
      if ( age > 90 ) {
        error = ERROR_TIMEOUT;
        return;
      }
    }
    while ( digitalRead(pin) == (i & 1) ? HIGH : LOW );

    if ( i >= 0 && (i & 1) ) {
      // Now we are being fed our 40 bits
      data <<= 1;

      // A zero max 30 usecs, a one at least 68 usecs.
      if ( age > 30 ) {
        data |= 1; // we got a one
      }
    }

    switch ( i ) {
      case 31:
        rawHumidity = data;
        break;
      case 63:
        rawTemperature = data;
        data = 0;
        break;
    }
  }

看起来很简单：D，我用这段代码尝试了第一部分，但它不起作用：

rtc_gpio_init(15);
rtc_gpio_set_direction(15, RTC_GPIO_MODE_INPUT_OUTPUT);

在我的 ulp 脚本文件中：

.set temp_humidity_sensor_pin, 13 // gpio 15 (adc 13)

send_start_signal:

    /* disable hold on gpio 15 (data pin) */
    WRITE_RTC_REG(RTC_IO_TOUCH_PAD3_REG, RTC_IO_TOUCH_PAD3_HOLD_S, 1, 0)

    /* switch to output mode */
    WRITE_RTC_REG(RTC_GPIO_OUT_W1TS_REG, RTC_GPIO_OUT_DATA_W1TS_S + temp_humidity_sensor_pin, 1, 1)

    /* send start signal (LOW) */
    WRITE_RTC_REG(RTC_GPIO_OUT_REG, RTC_GPIO_OUT_DATA_S + temp_humidity_sensor_pin, 1, 0)

    /* pull low for 800 microseconds (8Mhz) */
    wait    6400

    /* switch to input mode */
    WRITE_RTC_REG(RTC_GPIO_OUT_W1TC_REG, RTC_GPIO_OUT_DATA_W1TC_S + temp_humidity_sensor_pin, 1, 1)

    /* switch bus to receive data (HIGH) */
    WRITE_RTC_REG(RTC_GPIO_OUT_REG, RTC_GPIO_OUT_DATA_S + temp_humidity_sensor_pin, 1, 1)

wait_for_sensor_preparation_low:

    READ_RTC_REG(RTC_GPIO_IN_REG, RTC_GPIO_IN_NEXT_S + temp_humidity_sensor_pin, 1)
    and r0, r0, 1
    jump wait_for_sensor_preparation_low, eq

wait_for_sensor_preparation_high:

    READ_RTC_REG(RTC_GPIO_IN_REG, RTC_GPIO_IN_NEXT_S + temp_humidity_sensor_pin, 1) 
    and r0, r0, 0
    jump wait_for_sensor_preparation_high, eq

    jump wake_up // <-- never called :(

有什么想法吗？

Answer 1

您的“and r0, r0, 0”指令（接近尾声）总是将 r0 设置为零（根据定义，x & 0 == 0），这意味着下面的跳转指令将永远循环。请记住，“eq”标志并不真正意味着“相等”。它的意思是“零”。我想你想要：

wait_for_sensor_preparation_low:

    READ_RTC_REG(RTC_GPIO_IN_REG, RTC_GPIO_IN_NEXT_S + temp_humidity_sensor_pin, 1)
    and r0, r0, 1
    jump wait_for_sensor_preparation_high, eq
    jump wait_for_sensor_preparation_low

wait_for_sensor_preparation_high:

    READ_RTC_REG(RTC_GPIO_IN_REG, RTC_GPIO_IN_NEXT_S + temp_humidity_sensor_pin, 1) 
    and r0, r0, 1
    jump wait_for_sensor_preparation_high, eq

顺便说一句，我为 ULP 编写了一个 C 编译器，它应该会让您的生活更轻松。它在https://github.com/jasonful/lcc