[Serial] [Starlight Lightning STM32F407 Development Board] Chapter 5 Buzzer Experiment

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[Serial] [Starlight Lightning STM32F407 Development Board] Chapter 5 Buzzer Experiment [Copy link]

ChapterFiveChapter Buzzer Experiment 5.1 Purpose of the experiment The purpose of this experiment is to learn how to control the buzzer to make a buzzing sound through the IO port of STM32 and master the conventional control circuit of the buzzer. 5.2 Introduction to the experiment The buzzer is an electronic sound device with an integrated structure. It is powered by DC voltage and is widely used as a sound-generating device in electronic products such as computers, printers, copiers, alarms, electronic toys, automotive electronic equipment, telephones, timers, etc., as shown in the figure below.

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Figure5.2.1

Buzzers can be divided into passive buzzers and active buzzers. In simple terms, active buzzers will sound when DC is applied, while passive buzzers will sound when a square wave with a frequency of 2K--5K is used to drive them. Otherwise, they will not sound when DC is applied directly.

In this experiment, the IO port outputs a high level, the transistor Q1 is turned on, the collector is at a low level, and the buzzer sounds. 5.3 Circuit Design The buzzer control pin is connected to the PC13 pin of STM32, as shown in Figure 5.3.1, where R18 is a current limiting resistor and R19 is a pull-down resistor. When the control pin outputs a high level, the transistor is turned on and the buzzer sounds; when the output is a low level, the transistor is turned off and the buzzer stops sounding. When configuring the pin, PC13 can be configured as a push-pull output.

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Figure 5.3.1

5.4 Software Design

Open 3, program source code->1, basic experiment->experiment2buzzer experiment project in the CD directory, open the Beep.cfile under the BSP directory tree on the left, which is the driver file of the buzzer. The project directory is shown in the figure below,

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Figure 5.4.1

OpenBeep.c file, the code is as follows:

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Figure5.4.2

Openmain.c file, initialize the system clock and buzzer output pin configuration, and finally turn on or off the buzzer every1S in thewhileloop. The code is as follows

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Figure5.4.3

5.5 Download Verification

Use a MINI USB cable to connect the computer and the development board through the USB port of CN3, turn on the power switch to power on the development board, the D3 power indicator lights up, connect the JLINK/ST-LINK download debugger, and open "Experiment 2 "Buzzer Experiment"Project code, compile and download, the buzzer will sound for 1 second and stop for 1 second, and so on.

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