如何使用S/PDIF功能？

如果你使用HDMI显示器，可以将HOTPLUG_DET引脚拉高，激活S/PDIF功能。如果没有使用HDMI显示器，需要通过以下代码来激活：

// MixerSetOutputDevice.cpp : Defines the entry point for the console application.
 
#include <windows.h>
#include <winioctl.h>
 
//=============================================================================
// definitions for the MIX_MESSAGE IoControl
#define IOCTL_MIX_MESSAGE \ CTL_CODE((ULONG)0x8000, 0x0040, METHOD_BUFFERED, FILE_ANY_ACCESS)
 
 
// Definitions for the Nvidia SET_OUTPUT_DEVICE feature
#define MXDM_SET_OUTPUT_DEVICE (112)
#define WaveOutDevice_HDMI (4)
 
typedef struct {
    UINT uDeviceId;
    UINT uMsg;          // set to MXDM_SET_OUTPUT_DEVICE
    DWORD dwUser;
    DWORD dwParam1;     // set to WaveOutDevice_HDMI
    DWORD dwParam2;
} MMDRV_MESSAGE_PARAMS;
 
//=============================================================================
 
int _tmain(int argc, _TCHAR* argv[])
{
    HANDLE                  hWAV        = INVALID_HANDLE_VALUE; 
    DWORD                   ret; 
    MMDRV_MESSAGE_PARAMS    mixerParams = {0, MXDM_SET_OUTPUT_DEVICE, 0, WaveOutDevice_HDMI, 0};
    DWORD                   outBuf;
    DWORD                   outSize;
 
    hWAV = CreateFile(L"WAV1:", GENERIC_READ | GENERIC_WRITE, 0, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
 
    ret = DeviceIoControl(hWAV, IOCTL_MIX_MESSAGE, &mixerParams, sizeof(mixerParams), &outBuf , sizeof(outBuf), &outSize, NULL );
    if (!ret)
        printf("error in DeviceIoControl: %d, LastError=%d\r\n", ret, GetLastError());
 
    CloseHandle(hWAV);
    return 0;
}

如何配置SPDIF_OUT引脚?