首先说声对不起,在网上已经出现类似的帖子,
但因为我弄了两天都没有点响,所以在发帖;
c++代码可以点响;
DeviceIoControl(hPWM,2,&m_pwmvalue,sizeof(m_pwmvalue),NULL,NULL,NULL,NULL);// m_pwmvalue 是PWM的值 当PWM不为零时可以响;
我的c#代码是
using System;
using System.Linq;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Runtime.InteropServices;
using System.Threading;
namespace wincedida
{
unsafe public partial class Form2 : Form
{
public Form2()
{
InitializeComponent();
}
//控制蜂鸣器的步骤是1、打开流驱动接口2、操作硬件3、关闭流驱动接口
public class Beep
{
const UInt32 OPEN_EXISTING = 3;
const UInt32 GENERIC_READ = 0x80000000;
const UInt32 GENERIC_WRITE = 0x40000000;
const Int32 INVALID_HANDLE_VALUE = -1;
private IntPtr hPort;
// PWM的控制字,来源TQ2440/Src/Drivers/PWMDriver/PWMDriver.h文件
const UInt32 IOCTL_PWM_SET_PRESCALER = 1;
const UInt32 IOCTL_PWM_SET_DIVIDER = 2;
const UInt32 IOCTL_PWM_START = 2;
const UInt32 IOCTL_PWM_GET_FREQUENCY = 4;
//首先找到函数在dll库中的原型
//然后将该函数原型中的参数类型和C#中的数据类型进行比较得出C#的该函数原型如下
[DllImport("coredll.dll")]
public static extern IntPtr CreateFile(
String lpFileName,
UInt32 dwDesiredAccess,
UInt32 dwShareMode,
IntPtr lpSecurityAttributes,
UInt32 dwCreationDisposition,
UInt32 dwFlagsAndAttributes,
IntPtr hTemplateFile
);
[DllImport("coredll.dll")]
public static extern bool DeviceIoControl(
IntPtr hDevice,
UInt32 dwIoControlCode,
UInt32[] lpInBuffer,
UInt32 nInBufferSize,
Byte[] lpOutBuffer,
UInt32 nOutBufferSize,
UInt32 lpBytesReturned,
IntPtr lpOverlapped
);
[DllImport("coredll.dll")]
public static extern bool CloseHandle(IntPtr hDevice);
UInt32[] prescale = new UInt32[2] { 0, 15 };//15
UInt32[] divider = new UInt32[2] { 0, 8 };//8
UInt32[] buff = new UInt32[3] { 0, 488, 244 };//488,244来源
/*int freq = 800; // 工作频率初值
#define S3C2440_PCLK 50000000 // PCLK是50MHz
#define Prescaler0 15 // 预分频
#define MUX0 8 // 定时器分频值
#define TCNTB0 (S3C2440_PCLK/128/freq) // 工作频率
#define TCMPB0 (TCNTB0>>1) // 占空比,默认是50%
BYTE prescale[2] = {0, Prescaler0};
BYTE divider[2] = {0, MUX0};
DWORD buff[3] = {0, TCNTB0, TCMPB0};*/
public void BeepLoad()
{
hPort = CreateFile("PWM1:", GENERIC_READ | GENERIC_WRITE, 0, IntPtr.Zero, OPEN_EXISTING, 0, IntPtr.Zero);
if (hPort == (IntPtr)INVALID_HANDLE_VALUE)
{
MessageBox.Show("Open PWM Driver Fail");
}
DeviceIoControl(hPort, IOCTL_PWM_SET_PRESCALER, prescale, 2, null, 0, 0, IntPtr.Zero);
DeviceIoControl(hPort, IOCTL_PWM_SET_DIVIDER, divider, 2, null, 0, 0, IntPtr.Zero);
DeviceIoControl(hPort, IOCTL_PWM_START, buff, 3, null, 0, 0, IntPtr.Zero);
//Thread.Sleep(30);
//CloseHandle(hPort);
}
}
//定时器是每秒执行一次
private void timer1_Tick_1(object sender, EventArgs e)
{
new Beep().BeepLoad();
}
}
}
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