msp430 f5529外接DHT11代码

以下是 MSP430 F5529 外接 DHT11 的代码示例：

#include <msp430.h>
#include <stdint.h>

#define DHT11_PIN BIT0
#define DHT11_OUT P1OUT
#define DHT11_DIR P1DIR
#define DHT11_IN P1IN

void delay_ms(uint16_t ms) {
    while (ms--) {
        __delay_cycles(1000); // assuming 1 MHz clock
    }
}

void send_start_signal() {
    // pull down the data line for at least 18 ms
    DHT11_DIR |= DHT11_PIN;
    DHT11_OUT &= ~DHT11_PIN;
    delay_ms(20);

    // pull up the data line for 20-40 us
    DHT11_OUT |= DHT11_PIN;
    delay_ms(1);
    DHT11_DIR &= ~DHT11_PIN;
}

uint8_t read_byte() {
    uint8_t data = 0;
    for (int i = 0; i < 8; i++) {
        // wait for the data line to go high
        while ((DHT11_IN & DHT11_PIN) == 0);

        // wait for the data line to go low
        uint16_t count = 0;
        while ((DHT11_IN & DHT11_PIN) != 0) {
            if (++count > 1000) { // timeout after 1000 iterations
                return 0xFF; // error
            }
            __delay_cycles(2); // assuming 1 MHz clock
        }

        // if the data line was low for more than 30 us, set the bit to 1
        if (count > 15) {
            data |= (1 << (7 - i));
        }
    }
    return data;
}

uint8_t read_data(uint8_t* data) {
    // send start signal
    send_start_signal();

    // wait for the response from the DHT11
    uint16_t count = 0;
    while ((DHT11_IN & DHT11_PIN) != 0) {
        if (++count > 10000) { // timeout after 10000 iterations
            return 0xFF; // error
        }
        __delay_cycles(2); // assuming 1 MHz clock
    }

    // read the 5-byte data packet
    data[0] = read_byte();
    data[1] = read_byte();
    data[2] = read_byte();
    data[3] = read_byte();
    data[4] = read_byte();

    // verify the checksum
    if (data[0] + data[1] + data[2] + data[3] != data[4]) {
        return 0xFF; // error
    }

    return 0; // success
}

int main() {
    WDTCTL = WDTPW | WDTHOLD; // stop watchdog timer

    uint8_t data[5];
    uint8_t result = read_data(data);
    if (result == 0) {
        // data is valid, do something with it
        uint8_t humidity = data[0];
        uint8_t temperature = data[2];
        // ...
    } else {
        // data is invalid or there was a timeout
        // ...
    }

    while (1); // loop forever
}

注意：这是一个简单的示例代码，可能需要根据实际情况进行修改和优化。另外，DHT11 的通信协议比较特殊，需要精确控制时序和等待时间，否则会出现通信失败的情况。