Solved

Real-time timer

Posted on 2001-08-06
7
634 Views
Last Modified: 2010-04-06
I need a better timer than the TTimer component. I know there is no perfect timer under Windows 95, but what the TTimer does is quite unacceptable. (The TTimer gives on a 100 MHz Pentium, with the timer interval set to 1,  about 24 timer events per sec -- instead of 1000! Note that the test application was 'honest', doing nothing else in the OnTimer event handler than incrementing a counter.)

I have had the followings ideas.

1. Modifying the priority of the main thread, with the following code in the OnCreate method of the main form:

  mythread:=GetCurrentThread;
  SetThreadPriority(mythread,THREAD_PRIORITY_TIME_CRITICAL);

It makes ABSOLUTELY no difference.


2. Using the SetTimer API function with callback function instead of message posting. I haven't tried it, because the Win32 help says the following:

"When you specify a TimerProc callback function, the DispatchMessage function simply calls the callback function instead of the window procedure. Therefore, you need to dispatch messages in the calling thread, even when you use TimerProc instead of processing WM_TIMER."

So I have the feeling that it won't help me either.


3. Using a driver-level IRQ callback function.

I'm able to handle the IRQ interrupts under Delphi, using an external VxD which can call my Delphi code as callback function when an interrupt arrives, but I don't know whether the timer works with IRQ, and if so, what IRQ should I handle; I'm also not sure that the Windows 95 will share this IRQ with my VxD.


Waiting for ideas and comments,
Adam
0
Comment
Question by:biroadam
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
7 Comments
 
LVL 3

Accepted Solution

by:
tongalite earned 200 total points
ID: 6354998
Hi,
There are some timer comps about, I have a couple which I downloaded... a multimedia timer and a threaded timer (supposed to be very accurate to within 1 millisecond) that's supposed to do what you require. Untested yet though by me... Can't remember where I downloaded them but if you leave a temp e_mail address I will send them to you if you want.
have fun!
T.
0
 

Author Comment

by:biroadam
ID: 6355106
Hi tongalite!

Sounds pretty good!
My e-mail address is biroadam@softhome.net, I'm waiting for the components.

Best regards,
Adam
0
 
LVL 27

Expert Comment

by:kretzschmar
ID: 6355168
get this sample from simonet

entitled

How To Create High Precision Timers (Multimedia timers)
This project is aimed towards those that think Delphi's TTimer is not precise enought. The solution for that is to create a much more precise and reliable timer, a multimedia timer. This how-to project will teach you how to work with them and discuss when to use a multimedia timer and when to use a system timer (TTimer).  


http://www.bhnet.com.br/~simonet/archive/mmtimer.zip
0
Industry Leaders: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

 
LVL 22

Expert Comment

by:Mohammed Nasman
ID: 6355428
Hello

  you can find alot types of timers at torry site, and most of them free

http://www.torry.net/timers.htm

0
 

Author Comment

by:biroadam
ID: 6355586
Hi everybody!

The problem is actually very simple, there are two Windows API functions designed especially for realtime (multimedia) applications, called TimeSetEvent and a TimeKillEvent.

These functions work with a callback function rather than windows messages, and so they are quite accurate.

Actually I realised this reading the sample sent by kretzschmar, however the question is locked by tongalite.
Since I guess tongalite's answer is also correct (but I haven't received the components yet), I'll wait for it.

Thanks to everybody,
Adam
0
 
LVL 3

Expert Comment

by:tongalite
ID: 6356687
Sorry guys.... (and gals) Must have hit the proposed answer button when all I intended was to make a comment. I'll try not to let that happen again.

Adam,
The comps have been mailed.... Hope they are of use to you.
T.
0
 

Author Comment

by:biroadam
ID: 6356834
Hi tongalite,

As I was sure, your answer was as well as the others. There was only a TIMING problem...

Thank you again,
Adam
0

Featured Post

Technology Partners: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
Intraweb download file link ? 1 184
Delphi Form ownership 4 160
Strange behavior when a form is closed 6 79
Multi-layered image in FireMonkey 9 93
Introduction The parallel port is a very commonly known port, it was widely used to connect a printer to the PC, if you look at the back of your computer, for those who don't have newer computers, there will be a port with 25 pins and a small print…
In my programming career I have only very rarely run into situations where operator overloading would be of any use in my work.  Normally those situations involved math with either overly large numbers (hundreds of thousands of digits or accuracy re…
With Secure Portal Encryption, the recipient is sent a link to their email address directing them to the email laundry delivery page. From there, the recipient will be required to enter a user name and password to enter the page. Once the recipient …
This video shows how to use Hyena, from SystemTools Software, to update 100 user accounts from an external text file. View in 1080p for best video quality.

738 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question