我有一个应用程序，我需要在 Windows 7/32 位计算机上以 10 毫秒速率 (100hz) 运行（该计算机也将同时运行其他应用程序）。此中断可能有一些最小延迟 (100uSec) 响应，但不能长时间漂移。我有一个程序，我已加载并使用 NtSetTimerResolution 将计时器设置为 10 毫秒分辨率，然后使用 CreateTimerQueue/CreateTimereQueueTimer 函数创建一个计时器，该函数带有一个回调例程，用于切换 GPIO 引脚（暂时） - 这会产生预期的方波，只要我不对系统做任何其他事情。当我开始其他几个过程时，我的方波的准确性超出了窗口。有什么方法可以在定时器中断上获得更高的优先级（或者我可以使用另一个定时器）来产生更稳定的输出（也许是 SMI）？我的代码在下面，是使用 Windows DDK 的 x86 检查构建环境构建的，并从具有管理员权限的命令 shell 运行：
/*
Abstract:
Simple console test app for a 10mSec timer interrupt service
Enviroment:
Administrator Mode
*/
/* INCLUDES */
#include <windows.h>
#include <winioctl.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <conio.h>
#include <strsafe.h>
#include <stdlib.h>
#include <stdio.h>
#include <winsock2.h>
#include <mswsock.h>
#pragma warning(disable:4127) // condition expression is constant
FARPROC pNtQueryTimerResolution;
FARPROC pNtSetTimerResolution;
static HANDLE NTDLLModuleHandle;
static HINSTANCE hInpOutDll;
typedef void ( __stdcall *lpOut32 )( short , short );
typedef short ( __stdcall *lpInp32 )( short );
typedef BOOL ( __stdcall *lpIsInpOutDriverOpen )( void );
//Some global function pointers (messy but fine for an example)
lpOut32 gfpOut32;
lpInp32 gfpInp32;
lpIsInpOutDriverOpen gfpIsInpOutDriverOpen;
void CALLBACK TimerProc(void* lpParameter,
BOOLEAN TimerOrWaitFired);
// MAIN
VOID __cdecl main( void )
{
ULONG ulMinRes = 0;
ULONG ulMaxRes = 0;
ULONG ulCurRes = 0;
HANDLE phNewQueue;
HANDLE phNewTimer;
phNewQueue = CreateTimerQueue( );
NTDLLModuleHandle = LoadLibrary( "NTDLL.DLL" );
if( NULL == NTDLLModuleHandle )
{
return;
}
// Get the function pointers,
pNtQueryTimerResolution = GetProcAddress( NTDLLModuleHandle, "NtQueryTimerResolution" );
pNtSetTimerResolution = GetProcAddress( NTDLLModuleHandle, "NtSetTimerResolution" );
if( ( pNtQueryTimerResolution == NULL ) || ( pNtSetTimerResolution == NULL ) )
{
printf( "unable to link to ddl\n\n\n\n\n\n" );
return;
}
pNtQueryTimerResolution( &ulMinRes, &ulMaxRes, &ulCurRes );
printf( "MMR: %d %d %d\n", ulMinRes, ulMaxRes, ulCurRes );
ulMaxRes = 100000;
pNtSetTimerResolution( ulMaxRes, TRUE, &ulCurRes );
pNtQueryTimerResolution( &ulMinRes, &ulMaxRes, &ulCurRes );
printf( "MMR: %d %d %d\n", ulMinRes, ulMaxRes, ulCurRes );
//Dynamically load the DLL at runtime (not linked at compile time)
hInpOutDll = LoadLibrary( "InpOut32.DLL" );
if( hInpOutDll != NULL )
{
gfpOut32 = ( lpOut32 )GetProcAddress( hInpOutDll, "Out32" );
gfpInp32 = ( lpInp32 )GetProcAddress( hInpOutDll, "Inp32" );
gfpIsInpOutDriverOpen
= ( lpIsInpOutDriverOpen )GetProcAddress( hInpOutDll, "IsInpOutDriverOpen" );
if( gfpIsInpOutDriverOpen( ) )
{
gfpOut32( 0xA01, 0x00 );
}
else
{
printf( "unable to create timer system\n\n\n\n\n\n" );
return;
}
}
CreateTimerQueueTimer( &phNewTimer, phNewQueue, TimerProc, NULL, 0, 10,
WT_EXECUTEINTIMERTHREAD );
do
{
Sleep( 1 );
} while( TRUE );
}
void CALLBACK TimerProc(void* lpParameter,
BOOLEAN TimerOrWaitFired)
{
WORD wData;
UNREFERENCED_PARAMETER ( lpParameter );
UNREFERENCED_PARAMETER ( TimerOrWaitFired );
wData = gfpInp32( 0xA00 );
wData++;
gfpOut32( 0xA00, wData );
}