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Don't know about doing it from within a device driver, but it's "easy" from user mode.
Have a look at the DCB[^] structure, BuildCmmDCB, GetCommState and SetCommState.
Enjoy,
Iain.
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Hi, I'm using laptop Sony VGN-TZ398U[^] which is just purchase last month. The problem is when I fully charge the battery and turn it off and take it to use again 3 days later without touching it, i found that the battery reduce 30%. I don't know why this cause the problem. Could any one give me any idea about the cause of the problem? Thank in advance
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I can think of two possible reasons for that.
0. The battery is having a really high leak current and is emptying itself really quickly. Check if it's down to <50% after a week without touching it. If that is the case I would contact Sony for a replacement. Just keep in mind that leak currents go up quickly with temperature. So bad storage of the laptop might also be the reason.
1. The battery capacity is usually measured by its voltage. The problem is that the battery is reaching its max voltage already when it's 70 - 90% full (while charging) and that the rest of the charging takes pretty long time. The charging and discharging curves are also not identical and the battery meter is adjusted for the discharge curve.
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Jörgen Andersson wrote: The problem is that the battery is reaching its max voltage already when it's 70 - 90% full (while charging) and that the rest of the charging takes pretty long time
Thank you very much for your comment, But why does the battery already reach it ma voltage? Thank in advance
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It's a safety measure. You can learn more on the charging of Li-Ion batteries here[^], check page ten in the pdf.
Battery University[^] is also good reading.
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Lithium batteries may not fully charge at ambient high temperatures due to over temp protection.
Also all batteries have a self discharge rate: i.e. they start losing charge as soon as you disconnect the charger even if they are not being used. At 20deg C, a car battery will lose ~5% per month, Nickel Metal Hydride ~30% per month, Lithium ~3% per month. The discharge rates will increase significantly at higher temperatures.
Is it possible that there is still a drain on the batteries? For example do you hibernate the laptop instead of shutting it off? Do you have wake on lan or other settings turned on which will keep the computer running at low power?
If possible, charge the batteries fully, take them out of the laptop and put them in the refrigerator (NOT the freezer) for a few days. See what the charge is when you put them back into the laptop. If they are down more than a few percent they probably have an internal short, in which case you should definately stop using them and have them replaced.
Let us know what happens.
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Member 4723455 wrote: At 20deg C, a car battery will lose ~5% per month, Nickel Metal Hydride ~30% per month, Lithium ~3% per month. The discharge rates will increase significantly at higher temperatures.
This battery laptop lose 30% from 100% to 70% within 3 days without touching it. So it lose 10% for one day. I think that is the problem.
Member 4723455 wrote: Is it possible that there is still a drain on the batteries? For example do you hibernate the laptop instead of shutting it off? Do you have wake on lan or other settings turned on which will keep the computer running at low power?
I'm sure that I'm shutting down the computer, now hibernate. For the other option such as wake on LAN, I didn't configure anything yet. I just using this laptop after it came out of the box.
Member 4723455 wrote: If possible, charge the batteries fully, take them out of the laptop and put them in the refrigerator (NOT the freezer) for a few days. See what the charge is when you put them back into the laptop. If they are down more than a few percent they probably have an internal short, in which case you should definately stop using them and have them replaced.
Oh, I don't dare to do it.
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If it's brand new, out of the box, the battery meter has to "learn" the recharge and consumption curves. This takes time and it gets more acurate the more the power is drained from the battery and recharged.
Now, if the laptop stays powered off for a week and dies, then you've got a hardware issue with either the motherboard in the laptop or the battery.
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Dave Kreskowiak wrote: If it's brand new, out of the box, the battery meter has to "learn" the recharge and consumption curves. This takes time and it gets more acurate the more the power is drained from the battery and recharged.
I used it as a brand new out of the box nearly 2 months. So I think the battery meter already the recharged and consumption curves.
Dave Kreskowiak wrote: Now, if the laptop stays powered off for a week and dies, then you've got a hardware issue with either the motherboard in the laptop or the battery.
Is there any method that I could isolate and identified whether the problem come from battery, mother board or any hardware related issue? Thank for your comment!!!
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Yeah, replace one piece of hardware, like the battery, and watch what happens.
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charge the battery, remove it from the laptop for a few days, put it back in. That'll see if the battery is bad or something in the laptop is draining power.
Today's lesson is brought to you by the word "niggardly". Remember kids, don't attribute to racism what can be explained by Scandinavian language roots.
-- Robert Royall
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Mekong River wrote: For the other option such as wake on LAN, I didn't configure anything yet. I just using this laptop after it came out of the box.
How did it come configured out of the box? It is possible that Sony has enabled wake on lan, bluetooth, etc, so these features are using battery power even though the laptop is "off".
<blockquote class="FQ"><div class="FQA">Mekong River wrote:</div>Oh, I don't dare to do it.</blockquote>
The battery should just slide/snap in. You may need to release the lock(s), these will be slides as well. The laptop should run fine from the charger w/o the battery installed. If fact that is the recommended way to use if it is going to be powered from the charger all the time.
This would be the definitive test. If it loses 30% after 3 days in the frig, you definately have an internal short in the battery & should not continue to use it.
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are you sure that it`s not a operating system eror?!!
i`ve seen it on some vista based laptops too 
it`s Bcuz in vista the red botten that has the logo of shutdown just takes takes it on sleep mode !!!
if you have vista operating system ... might the same problem 
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Yes, I'm sure that I'm shutdown, not sleep mode. Because I already properly choose shutdown from the drop down menu.
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Mekong River wrote: Yes, I'm sure that I'm shutdown, not sleep mode. Because I already properly choose shutdown from the drop down menu.
On my XP Desktop system and too lazy to go to the car andd get my laptop so my instructions maybe out of sorts. But to shutdown Vista, click the Start Button then look to the bottom right of the menu, you will see an arrow head pointing to the right, click it and select shutdown from the fly out menu. Any other method from the menu I believe just puts in in sleep/suspend.
Michael Martin
Australia
"I controlled my laughter and simple said "No,I am very busy,so I can't write any code for you". The moment they heard this all the smiling face turned into a sad looking face and one of them farted. So I had to leave the place as soon as possible."
- Mr.Prakash One Fine Saturday. 24/04/2004
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Just set up a laptop to dual boot XP/Linux. Everything went well after the third or fourth try. (I am not an M$ fan, but Linux still has a few things to learn about documentation/ease of use).
Linux side works fine, good connectivity with wireless card to any available access point. So back to the XP side & oops – no wireless connection.
Go to View networks and no networks found. Hmmm…
Fire up netstumbler and it finds 6 available networks and the card connects to the last used AP.
Back to View Networks & still no networks found.
I am thinking perhaps the Linux drivers have put the card in a mode that is not recognized by Windows.
Re-booted - no change. Powered down – no change.
Reinstalled windows network drivers, turned off Zero Config. Turned zero config back on.
Still no available networks viewed and card will not connect (until Netstumbler is run).
This lappie has XP SR3 and an internal Intel 2200 wireless card.
Can anyone offer an idea what is going on?
Thanks!
Update: Cured by reinstalling Windows. But still curious if anyone else has seen this, a web search did not turn up a solution.
modified on Wednesday, November 19, 2008 2:58 PM
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Reported as spam. No advertising in the forums. Buy the ad space like everyone else...
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I am sorry for the spam,I find the people come here are mostly the specialist on software,my company want to develop a Java SDK for our product,seems not so many software designers understand our products,so maybe any one can give me a reference about what the cost will be to develop a Java SDK for our UHF RFID Reader?
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it mostly seems like a spam ! 
isn it?
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oh,I am sorry,no second times, 
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hi
i am new for the usb device driver coding. i dont know how to start writing the usb device driver coding.
we developed the embedded device(POS). we have to retrive the data from POS device to PC through USB. to communicate with the PC i have to develop the driver.
i am going to develop the driver in VB.net or C#.i am expecting some sample codings regarding usb device driver.
please help me out. thanking you
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Oh you're expecting sample code, are you? Have you tried a Google search, or looking at books at all?
Regards,
--Perspx
"A refund for defective software might be nice, except it would bankrupt the entire software industry in the first year."
-Andrew Tanenbaum
"Einstein argued that there must be simplified explanations of nature, because God is not capricious or arbitrary. No such faith comforts the software engineer."
-Fred Brooks
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You're not going to find any examples of writing a device driver in VB.NET or C#. You'll find tons of them in C++ though.
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Dave Kreskowiak wrote: You'll find tons of them in C++ though.
Not really. You might find a few in C++ but since Microsoft dont support C++ in the kernel you will find almost all driver code in C.
Morality is indistinguishable from social proscription
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Drivers are c/c++, with the former preferred due to its stricter controls over memory layout.
Today's lesson is brought to you by the word "niggardly". Remember kids, don't attribute to racism what can be explained by Scandinavian language roots.
-- Robert Royall
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