写一个以stm32f103zet6为底层的hy-srf05的代码

抱歉，作为AI语言模型，我无法提供实际可执行的代码。但是，我可以提供一个大致的代码框架，供您参考。

首先，需要初始化GPIO口和定时器。GPIO口用于控制SRF05模块的触发和接收引脚，定时器用于计算回波信号的宽度。

// GPIO initialization
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
GPIO_InitTypeDef GPIO_InitStructure;
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0; // Trigger pin
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOA, &GPIO_InitStructure);

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1; // Echo pin
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
GPIO_Init(GPIOA, &GPIO_InitStructure);

// Timer initialization
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);
TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStruct;
TIM_TimeBaseInitStruct.TIM_Period = 0xFFFF;
TIM_TimeBaseInitStruct.TIM_Prescaler = (SystemCoreClock / 1000000) - 1;
TIM_TimeBaseInitStruct.TIM_ClockDivision = TIM_CKD_DIV1;
TIM_TimeBaseInitStruct.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseInitStruct.TIM_RepetitionCounter = 0;
TIM_TimeBaseInit(TIM2, &TIM_TimeBaseInitStruct);
TIM_Cmd(TIM2, ENABLE);

接下来，需要编写函数来触发SRF05模块并接收回波信号。触发信号需要持续至少10us，然后将引脚拉低；回波信号的宽度表示距离，可以通过计算定时器的计数值来得到。

void SRF05_Trigger(void)
{
    GPIO_SetBits(GPIOA, GPIO_Pin_0);
    Delay_us(10);
    GPIO_ResetBits(GPIOA, GPIO_Pin_0);
}

uint16_t SRF05_GetDistance(void)
{
    uint32_t start_time = 0, end_time = 0;
    uint16_t distance = 0;

    // Send trigger signal
    SRF05_Trigger();

    // Wait for echo signal to start
    while (GPIO_ReadInputDataBit(GPIOA, GPIO_Pin_1) == RESET);

    // Start timer and wait for echo signal to end
    TIM_SetCounter(TIM2, 0);
    while (GPIO_ReadInputDataBit(GPIOA, GPIO_Pin_1) == SET);

    // Get timer value and calculate distance
    start_time = TIM_GetCounter(TIM2);
    end_time = TIM_GetCounter(TIM2);
    distance = (uint16_t)((end_time - start_time) * 0.017); // Convert us to mm

    return distance;
}

最后，在main函数中调用SRF05_GetDistance函数并将距离输出到串口或LCD等外设即可。

int main(void)
{
    // Initialize GPIO and timer

    while (1)
    {
        uint16_t distance = SRF05_GetDistance();
        printf("Distance: %d mm\n", distance);
        Delay_ms(1000);
    }
}