stm32F1 uses us-100 ultrasonic ranging

As always, use CubeMX for peripheral configuration.

Using the level mode requires two captures, and sending a 10us trigger pulse requires a delay. 103VBT6 does not have many timers, so the UART port is more convenient.

Hardware Configuration:

1) Set the UART baud rate to 9600

2) Enable NVIC interrupt

software:

I use US-100 to measure the consumption of pellets in the hopper. The project uses FreeRTOS system.

1)

Enable UART2 port monitoring in the main function

1. HAL_UART_Receive_IT(&huart2, rx_data_sonic, 2);  

After triggering the module, it will return 2 bytes of data, and we will read 2 bytes directly here.

2)

In the Task, it is triggered every 10 seconds and a byte 0x55 is sent. The task runs every 20ms and uses a count.

1. check_interval++;  

2. if (check_interval >= 499) {  

3.   HAL_UART_Transmit(&huart2, &command_sonic, 1, 1);  

4.   check_interval = 0;  

5. }  

3)

Do calculations in the interrupt callback function.

The hopper height is 50 cm, so the returned value is limited. For example, if the hopper cover is opened, the data of several meters measured will be thrown away. There is no need to consider the case where the hopper is opened.

1. //Ultrasonic data  

2. if (huart->Instance == USART2) {  

3.   uint16_t distance = rx_data_sonic[0]*256 + rx_data_sonic[1];  

4.     

5.   if (Q_SonicDataHandle != NULL) {  

6.     if (distance < 500) {  

7.       osMessagePut(Q_SonicDataHandle, (uint32_t)distance, 0);  

8.     }  

9.   }  

10.   HAL_UART_Receive_IT(&huart2, rx_data_sonic, 2);   

11.     

12. }  

At the end of the statement, you need to start the serial port interrupt monitoring again.