2024-07-11 18:14:13 +08:00
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#include "hcsr04.h"
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#include "tim.h"
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// time 的单位是 μs
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2024-07-12 14:16:50 +08:00
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static uint64_t time; // 声明变量,用来计时
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static uint64_t time_end; // 声明变量,存储回波信号时间
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static uint8_t state = 1;
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2024-07-11 18:14:13 +08:00
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// HACK 临时的 delay 解决方法
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void delay_us(uint16_t us);
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int16_t sonar_mm(void) // 测距并返回单位为毫米的距离结果
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{
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uint32_t distance, distance_mm = 0;
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HAL_GPIO_WritePin(SCL_C_GPIO_Port, SCL_C_Pin, GPIO_PIN_SET); // 输出高电平
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delay_us(15); // 延时15微秒
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HAL_GPIO_WritePin(SCL_C_GPIO_Port, SCL_C_Pin, GPIO_PIN_RESET); // 输出低电平
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while (state)
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;
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state = 1;
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// BUG 现在 time 的单位是 1μs
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if (time_end / 100 < 38) // 判断是否小于38毫秒,大于38毫秒的就是超时,直接调到下面返回0
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{
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distance = (time_end * 346) / 2; // 计算距离,25°C空气中的音速为346m/s
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distance_mm = distance / 100; // 因为上面的time_end的单位是10微秒,所以要得出单位为毫米的距离结果,还得除以100
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}
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return distance_mm; // 返回测距结果
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}
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float sonar(void) // 测距并返回单位为米的距离结果
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{
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uint32_t distance, distance_mm = 0;
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float distance_m = 0;
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HAL_GPIO_WritePin(SCL_C_GPIO_Port, SCL_C_Pin, GPIO_PIN_SET); // 输出高电平
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delay_us(15); // 延时15微秒
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HAL_GPIO_WritePin(SCL_C_GPIO_Port, SCL_C_Pin, GPIO_PIN_RESET); // 输出低电平
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while (state)
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;
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state = 1;
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// BUG 现在 time 的单位是 1μs
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if (time_end / 100 < 38)
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{
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distance = (time_end * 346) / 2;
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distance_mm = distance / 100;
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distance_m = distance_mm / 1000;
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}
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return distance_m;
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}
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void delay_us(uint16_t us)
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{
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HAL_TIM_Base_Start_IT(&htim2);
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time = 0;
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while (time < us)
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;
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HAL_TIM_Base_Stop_IT(&htim2);
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}
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void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *htim)
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{
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if (htim == &htim2)
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++time;
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}
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void HAL_GPIO_EXTI_Callback(uint16_t GPIO_Pin)
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{
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if (GPIO_Pin == SDA_C_EXTI12_Pin)
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{
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if (HAL_GPIO_ReadPin(SDA_C_EXTI12_GPIO_Port, SDA_C_EXTI12_Pin))
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{
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HAL_TIM_Base_Start_IT(&htim2);
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time = 0;
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}
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else
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{
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time_end = time;
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HAL_TIM_Base_Stop_IT(&htim2);
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state = 0;
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}
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}
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}
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