使用異步定時器編寫一個數(shù)據(jù)采集的多線程程序

1、實(shí)驗七任務(wù)使用異步定時器編寫一個數(shù)據(jù)采集的多線程程序，和普通定時器比較二者運(yùn)行時的差異。實(shí)驗步驟步驟1：設(shè)計程序界面，生成程序框架。根據(jù)實(shí)驗要求，我們在面板上放置兩個帶狀圖控件，分別用于顯示異步定時器和普通定時器的采樣結(jié)果；放置一雙態(tài)按鈕來控制數(shù)據(jù)采集的開始和關(guān)閉。最終界面如圖9-1所示，其主要控件的基本屬性列表見表9-1。圖9-1 最終用戶界面表9-1 主要控件基本屬性列表控件類型constant name 屬性設(shè)置面板panelpanel命令按鈕command buttonquitbuttoncallback functionquitcallbacklable_quit雙態(tài)按鈕toggle

2、 buttontogglebuttoncallback functiondaqcontrolcbinitial stateofflable數(shù)據(jù)定時器控件timertimercallback functiondataaquirtimercbinterval (seconds)1.0帶狀圖控件strip chartstripchartlable普通定時器stripchart_2lable異步定時器步驟2：添加異步定時器。把異步定時器的儀器驅(qū)動程序添加到當(dāng)前工程，在工程窗口選擇editadd file to projectinstrument(*.fp)，路徑為cvitoolslibtoolboxa

3、synctmr.fp。步驟3：獲得異步定時器句柄，在main函數(shù)添加如下語句：static int asynctimerid;/*先聲明句柄變量*/int main (int argc, char *argv)if (initcvirte (0, argv, 0) = 0)return -1;/* out of memory */if (panelhandle = loadpanel (0, lesson9.uir, panel) 0)return -1;displaypanel (panelhandle); /*獲得異步定時器句柄*/asynctimerid=newasynctimer (1

4、.0, -1, 0, asynctimercb, 0);runuserinterface ();discardpanel (panelhandle);return 0;步驟4：聲明異步定時器回調(diào)函數(shù)。在main函數(shù)之前聲明。/*聲明asynctimercb*/int cvicallback asynctimercb (int reserved, int timerid, int event, void *callbackdata, int eventdata1, int eventdata2);步驟5：編寫回調(diào)函數(shù)。/*雙態(tài)按鈕回調(diào)函數(shù)daqcontrolcb*/int cvicallback

5、 daqcontrolcb (int panel, int control, int event,void *callbackdata, int eventdata1, int eventdata2)int i;switch (event)case event_commit:getctrlval (panelhandle, panel_togglebutton, &i);setctrlattribute (panelhandle, panel_timer, attr_enabled, i);setasynctimerattribute (asynctimerid, async_attr_ena

6、bled, i);break;return 0;/*普通定時器回調(diào)函數(shù)dataaquirtimercb*/int cvicallback dataaquirtimercb (int panel, int control, int event,void *callbackdata, int eventdata1, int eventdata2)double data;switch (event)case event_timer_tick:data=(double)rand ()/rand_max*100.0;plotstripchartpoint (panelhandle, panel_stripchart_2, data);break;return 0;/*異步定時器回調(diào)函數(shù)asynctimercb */int cvicallback asynctimercb (int reserved, int timerid, int event, void *callbackdata, int eventdata1, int eventdata2)double data;switch (event)case event_timer_tick:data=(double)rand ()/rand_max*100.0;plotstr