5 单总线1-Wire里面的us级延时占用cpu时间太长

发布于 2021-09-30 17:28:10 浏览：1101 订阅该版

单总线1-Wire里面的us级延时占用cpu时间太长，还不能取消掉，有什么办法能把这段时间释放掉让cpu干其他的事情，我用的stm32H743，480M主频加了这个ds18b20明显降低了效率。
```c
static void ds18b20_reset(rt_base_t pin)
{
    rt_pin_mode(pin, PIN_MODE_OUTPUT);
    rt_pin_write(pin, PIN_LOW);
    rt_hw_us_delay(750);               /* 480us - 960us */
    rt_pin_write(pin, PIN_HIGH);
    rt_hw_us_delay(25);                /* 15us - 60us*/
}
static uint8_t ds18b20_read_bit(rt_base_t pin)
{
    uint8_t data;

rt_pin_mode(pin, PIN_MODE_OUTPUT);
    rt_pin_write(pin, PIN_LOW);
    rt_hw_us_delay(2);
    rt_pin_write(pin, PIN_HIGH);
    rt_pin_mode(pin, PIN_MODE_INPUT);
    /* maybe 12us, maybe 5us, whatever...I have no idea */
    rt_hw_us_delay(5);

if(rt_pin_read(pin))
        data = 1;
    else
        data = 0;

rt_hw_us_delay(50);

return data;
}
static void ds18b20_write_byte(rt_base_t pin, uint8_t dat)
{
    uint8_t j;
    uint8_t testb;
    rt_pin_mode(pin, PIN_MODE_OUTPUT);

for (j = 1; j <= 8; j++)
    {
        testb = dat & 0x01;
        dat = dat >> 1;

if(testb)
        {
            rt_pin_write(pin, PIN_LOW);
            rt_hw_us_delay(2);
            rt_pin_write(pin, PIN_HIGH);
            rt_hw_us_delay(60);
        }
        else
        {
            rt_pin_write(pin, PIN_LOW);
            rt_hw_us_delay(60);
            rt_pin_write(pin, PIN_HIGH);
            rt_hw_us_delay(2);
        }
    }
}
```