microcontroller - Assembly - using more than 2 buttons for interrupts? -


i using stk200 board atmega8535 microcontroller. use int0 , int1 buttons external interrupts, in order initialize int0 have set bit 6 1 , intialize int1 have set bit 7 1, there no more space initialize other buttons.

i have been told lecturer possible use more buttons cause interrupts above knowledge required year studying (1st year software engineering).

without interrupts, have no idea how handle buttons. need either suggestions how handle buttons or how use more buttons interrupts.

there way handling buttons(different interrupts), of course interrupts best, if don't have external interrupt pins left, use this. method polling pin have connected button. i'll post code implementation in asm 8051, can understand better. hope helps:

;assume have connected button p1.1

org 00h  jb p1.1,$      ;wait hold button      jnb p1.1,$     ;wait button unhold  ;perform  end

as can see in second line of code check if button pressed(assuming button active low of course), if wasn't stay there, if pressed jump line 3 wait until button unholded. if don't wait until btn unholded microprocessor perform ehat want lots of times 1 press btn.the cause of simple:the frequency of mp(could 12mhz) faster frequency of finger pressing button,or,in other words: can press button fast can mp faster you:). note: interrupts better simple reason: don't have polling.

hope understand.


Comments

Post a Comment

Popular posts from this blog

ios - iPhone/iPad different view orientations in different views , and apple approval process -

i force app's home screen portrait , other views landscape. apple rejects app if this? if not , how force first screen launch in portrait mode? , force other screens launch in landscape. this not duplicate question search every possible answer in website. i force app's home screen portrait , other views landscape. apple rejects app if this? no apple not reject app this. have lot of apps doesn't support orientation. forcing on 1 screen won't cause app reject. if not , how force first screen launch in portrait mode? , force other screens launch in landscape. can on write : -(nsuinteger)supportedinterfaceorientations; function.
Read more

java Extracting Zip file -

i'm looking way extract zip file. far have tried java.util.zip , org.apache.commons.compress, both gave corrupted output. basically, input zip file contain 1 single .doc file. java.util.zip: output corrupted. org.apache.commons.compress: output blank file, 2 mb size. so far commercial software winrar work perfectly. there java library make use of this? this method using java.util library: public void extractzipnative(file filezip) { zipinputstream zis; stringbuilder sb; try { zis = new zipinputstream(new fileinputstream(filezip)); zipentry ze = zis.getnextentry(); byte[] buffer = new byte[(int) ze.getsize()]; fileoutputstream fos = new fileoutputstream(this.tempfolderpath+ze.getname()); int len; while ((len=zis.read(buffer))>0) { fos.write(buffer); } fos.flush(); fos.close(); } catch (filenotfoundexception e) { // todo auto-generated catch block ...
Read more

C# WinForm - loading screen -

i ask how make loading screen (just picture or something) appears while program being loaded, , disappears when program has finished loading. in fancier versions, have seen process bar (%) displayed. how can have that, , how calculate % show on it? i know there form_load() event, not see form_loaded() event, or % property / attribute anywhere. all need create 1 form splash screen , show before main start showing landing page , close splash once landing page loaded. class splashform { //delegate cross thread call close private delegate void closedelegate(); //the type of form displayed splash screen. private static splashform splashform; static public void showsplashscreen() { // make sure launched once. if (splashform != null) return; thread thread = new thread(new threadstart(splashform.showform)); thread.isbackground = true; thread.setapartmentstate(apartmentstate.sta); thread....
Read more