I use HM-10 board (CC2541 inside) with HM-Soft V540 firmware to make IBeacon devices.
But I have a big problem: I configure the HM10 as a beacon, with auto-sleep etc etc, after reset, the HM-10 is sleeping and advertising (2µA when sleep) but after a random time (a few seconds or a few minutes), the HM10 wake up and consume between 15 and 20mA... all the time !! Until I send "AT+RESET" for re-apply the sleeping. (and again, wake up after some seconds...)
This is the commands that I used to set the HM10:
AT+RENEW
AT+RESET
AT
AT+MARJ0x1234
AT+MINO0xFA01
AT+ADVI9
AT+NAMEFAB1
AT+ADTY3
AT+IBEA1
AT+DELO2
AT+PWRM0
AT+RESET
Do you know where is this issue ??
Thanks a lot for your help.
You should change your PWRM0 to PWRM1 worked for me
Guess the problem might be solved for you but as I just run into the same "issue" with the HM-10 (firmware version v549) I wanted to share my solution/finding:
In my case I have figured out that some logger within my code is sending a string of characters via serial extending 80 char. This is actually also the rule that forces the HM-10 to wake up from sleep. So you might use AT+PWRM0 (which enables autosleep) but also make sure that when sending data over serial the string length might not wake up the HM-10 accidentally. Hope this helps a bit.
I'm planning on making a clock. An actual clock, not something for Windows. However, I would like to be able to write most of the code now. I'll be using a PIC16F628A to drive the clock, and it has a timer I can access (actually, it has 3, in addition to the clock it has built in). Windows, however, does not appear to have this function. Which makes making a clock a bit hard, since I need to know how long it's been so I can update the current time. So I need to know how I can get a pulse (1Hz, 1KHz, doesn't really matter as long as I know how fast it is) in Windows.
There are many timer objects available in Windows. Probably the easiest to use for your purposes would be the Multimedia Timer, but that's been deprecated. It would still work, but Microsoft recommends using one of the new timer types.
I'd recommend using a threadpool timer if you know your application will be running under Windows Vista, Server 2008, or later. If you have to support Windows XP, use a Timer Queue timer.
There's a lot to those APIs, but general use is pretty simple. I showed how to use them (in C#) in my article Using the Windows Timer Queue API. The code is mostly API calls, so I figure you won't have trouble understanding and converting it.
The LARGE_INTEGER is just an 8-byte block of memory that's split into a high part and a low part. In assembly, you can define it as:
MyLargeInt equ $
MyLargeIntLow dd 0
MyLargeIntHigh dd 0
If you're looking to learn ASM, just do a Google search for [x86 assembly language tutorial]. That'll get you a whole lot of good information.
You could use a waitable timer object. Since Windows is not a real-time OS, you'll need to make sure you set the period long enough that you won't miss pulses. A tenth of a second should be safe most of the time.
Additional:
The const LARGE_INTEGER you need to pass to SetWaitableTimer is easy to implement in NASM, it's just an eight byte constant:
period: dq 100 ; 100ms = ten times a second
Pass the address of period as the second argument to SetWaitableTimer.
I am working on a Windows NDIS driver using the latest WDK that is in need of a millisecond resolution kernel time counter that is monotonically non-decreasing. I looked through MSDN as well as WDK's documentation but found nothing useful except something called TsTime, which I am not sure whether is just a made-up name for an example or an actual variable. I am aware of NDISGetCurrentSystemTime, but would like to have something that is lower-overhead like ticks or jiffies, unless NDISGetCurrentSystemTime itself is low-overhead.
It seems that there ought to be a low-overhead global variable that stores some sort of kernel time counter. Anyone has insight on what this may be?
Use KeQueryTickCount. And perhaps use KeQueryTimeIncrement once to be able to convert the tick count into a more meaningful time unit.
How about GetTickCount / GetTickCount64 (Check the reqs on the latter)
I'm creating a game engine using wxWidgets and OpenGL. I'm trying to set up a timer so the game can be updated regularly. I don't want to use wxTimer, because it's probably not accurate enough for what I need. I'm using a while (true) and a wxStopWatch:
while (true) {
stopWatch.Start();
<handle events> // I need a function for this
game->OnUpdate();
game->Refresh();
if (stopWatch.Time() < 1000 / 60)
wxMilliSleep(1000 / 60 - stopWatch.Time());
}
What I need is a function that will handle all the wxWidgets events, because right now my app just freezes.
UPDATE: It doesn't. It's slightly jerky on Windows, and when tested on a Mac, it was extremely jerky. Apparently EVT_IDLE doesn't get called consistently on Windows, and even less on a Mac.
UPDATE2: It actually mostly does. It's fine on a Mac; I misunderstood my Mac tester's reply.
Instead of using a while (true) loop, I'm using EVT_IDLE, and it works perfectly.
UPDATE: It doesn't. It's slightly jerky on Windows, and when tested on a Mac, it was extremely jerky. Apparently EVT_IDLE doesn't get called consistently on Windows, and even less on a Mac.
UPDATE2: It actually mostly does. It's fine on a Mac; I misunderstood my Mac tester's reply.
"ave you requested idle events to be generated at the maximum rate? You have to call RequestMore() on the event, if you don't you will get the next idle event only after some other event has been processed. Note that constant idle processing will cause 100% CPU load on one core."
This works, I have the following code in a graphical window:-
BEGIN_EVENT_TABLE(MyCanvas, wxScrolledWindow)
EVT_PAINT (MyCanvas::OnPaint)
EVT_IDLE(MyCanvas::OnIdle)
EVT_MOTION (MyCanvas::OnMouseMove)
END_EVENT_TABLE()
The canvas needs to be updated when my_canvas->Refresh(bClearBackground) is called and not otherwise. To do this I needed to make a modification as the program was eating up half of the cpu time (or 100% of 1 cpu on a duel core).
void MyCanvas::OnIdle(wxIdleEvent &event)
{
wxPaintEvent unused;
OnPaint(unused);
event.RequestMore(false);
}
Setting the parameter of RequestMore() to false makes the app only ask for more when its needed, i.e. only when Refresh() has been called.
Have you requested idle events to be generated at the maximum rate? You have to call RequestMore() on the event, if you don't you will get the next idle event only after some other event has been processed. Note that constant idle processing will cause 100% CPU load on one core.
Even if you request more idle events you can't be sure how long it will take for the next one to arrive. Therefore to get smooth animation you will need to calculate the elapsed time since the last event, and update the display accordingly.
I've developed a Windows service which tracks business events. It uses the Windows clock to timestamp events. However, the underlying clock can drift quite dramatically (e.g. losing a few seconds per minute), particularly when the CPUs are working hard. Our servers use the Windows Time Service to stay in sync with domain controllers, which uses NTP under the hood, but the sync frequency is controlled by domain policy, and in any case even syncing every minute would still allow significant drift. Are there any techniques we can use to keep the clock more stable, other than using hardware clocks?
Clock ticks should be predictable, but on most PC hardware - because they're not designed for real-time systems - other I/O device interrupts have priority over the clock tick interrupt, and some drivers do extensive processing in the interrupt service routine rather than defer it to a deferred procedure call (DPC), which means the system may not be able to serve the clock tick interrupt until (sometimes) long after it was signalled.
Other factors include bus-mastering I/O controllers which steal many memory bus cycles from the CPU, causing it to be starved of memory bus bandwidth for significant periods.
As others have said, the clock-generation hardware may also vary its frequency as component values change with temperature.
Windows does allow the amount of ticks added to the real-time clock on every interrupt to be adjusted: see SetSystemTimeAdjustment. This would only work if you had a predictable clock skew, however. If the clock is only slightly off, the SNTP client ("Windows Time" service) will adjust this skew to make the clock tick slightly faster or slower to trend towards the correct time.
I don't know if this applies, but ...
There's an issue with Windows that if you change the timer resolution with timeBeginPeriod() a lot, the clock will drift.
Actually, there is a bug in Java's Thread wait() (and the os::sleep()) function's Windows implementation that causes this behaviour. It always sets the timer resolution to 1 ms before wait in order to be accurate (regardless of sleep length), and restores it immediately upon completion, unless any other threads are still sleeping. This set/reset will then confuse the Windows clock, which expects the windows time quantum to be fairly constant.
Sun has actually known about this since 2006, and hasn't fixed it, AFAICT!
We actually had the clock going twice as fast because of this! A simple Java program that sleeps 1 millisec in a loop shows this behaviour.
The solution is to set the time resolution yourself, to something low, and keep it there as long as possible. Use timeBeginPeriod() to control that. (We set it to 1 ms without any adverse effects.)
For those coding in Java, the easier way to fix this is by creating a thread that sleeps as long as the app lives.
Note that this will fix this issue on the machine globally, regardless of which application is the actual culprit.
You could run "w32tm /resync" in a scheduled task .bat file. This works on Windows Server 2003.
Other than resynching the clock more frequently, I don't think there is much you can do, other than to get a new motherboard, as your clock signal doesn't seem to be at the right frequency.
http://www.codinghorror.com/blog/2007/01/keeping-time-on-the-pc.html
PC clocks should typically be accurate to within a few seconds per day. If you're experiencing massive clock drift-- on the order of minutes per day-- the first thing to check is your source of AC power. I've personally observed systems with a UPS plugged into another UPS (this is a no-no, by the way) that gained minutes per day. Removing the unnecessary UPS from the chain fixed the time problem. I am no hardware engineer, but I'm guessing that some timing signal in the power is used by the real-time clock chip on the motherboard.
As already mentioned, Java programs can cause this issue.
Another solution that does not require code modification is adding the VM argument -XX:+ForceTimeHighResolution (found on the NTP support page).
9.2.3. Windows and Sun's Java Virtual Machine
Sun's Java Virtual Machine needs to be started with the >-XX:+ForceTimeHighResolution parameter to avoid losing interrupts.
See http://www.macromedia.com/support/coldfusion/ts/documents/createuuid_clock_speed.htm for more information.
From the referenced link (via the Wayback machine - original link is gone):
ColdFusion MX: CreateUUID Increases the Windows System Clock Speed
Calling the createUUID function multiple times under load in
Macromedia ColdFusion MX and higher can cause the Windows system clock
to accelerate. This is an issue with the Java Virtual Machine (JVM) in
which Thread.sleep calls less than 10 milliseconds (ms) causes the
Windows system clock to run faster. This behavior was originally filed
as Sun Java Bug 4500388
(developer.java.sun.com/developer/bugParade/bugs/4500388.html) and has
been confirmed for the 1.3.x and 1.4.x JVMs.
In ColdFusion MX, the createUUID function has an internal Thread.sleep
call of 1 millisecond. When createUUID is heavily utilized, the
Windows system clock will gain several seconds per minute. The rate of
acceleration is proportional to the number of createUUID calls and the
load on the ColdFusion MX server. Macromedia has observed this
behavior in ColdFusion MX and higher on Windows XP, 2000, and 2003
systems.
Increase the frequency of the re-sync.
If the syncs are with your own main server on your own network there's no reason not to sync every minute.
Sync more often. Look at the Registry entries for the W32Time service, especially "Period". "SpecialSkew" sounds like it would help you.
Clock drift may be a consequence of the temperature; maybe you could try to get temperature more constant - using better cooling perhaps? You're never going to loose drift totally, though.
Using an external clock (GPS receiver etc...), and a statistical method to relate CPU time to Absolute Time is what we use here to synch events in distributed systems.
Since it sounds like you have a big business:
Take an old laptop or something which isn't good for much, but seems to have a more or less reliable clock, and call it the Timekeeper. The Timekeeper's only job is to, once every (say) 2 minutes, send a message to the servers telling the time. Instead of using the Windows clock for their timestamps, the servers will put down the time from the Timekeeper's last signal, plus the elapsed time since the signal. Check the Timekeeper's clock by your wristwatch once or twice a week. This should suffice.
What servers are you running? In desktops the times I've come across this are with Spread Spectrum FSB enabled, causes some issues with the interrupt timing which is what makes that clock tick. May want to see if this is an option in BIOS on one of those servers and turn it off if enabled.
Another option you have is to edit the time polling interval and make it much shorter using the following registry key, most likely you'll have to add it (note this is a DWORD value and the value is in seconds, e.g. 600 for 10min):
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\TimeProviders\NtpClient\SpecialPollInterval
Here's a full workup on it: KB816042
I once wrote a Delphi class to handle time resynchs. It is pasted below. Now that I see the "w32tm" command mentioned by Larry Silverman, I suspect I wasted my time.
unit TimeHandler;
interface
type
TTimeHandler = class
private
FServerName : widestring;
public
constructor Create(servername : widestring);
function RemoteSystemTime : TDateTime;
procedure SetLocalSystemTime(settotime : TDateTime);
end;
implementation
uses
Windows, SysUtils, Messages;
function NetRemoteTOD(ServerName :PWideChar; var buffer :pointer) : integer; stdcall; external 'netapi32.dll';
function NetApiBufferFree(buffer : Pointer) : integer; stdcall; external 'netapi32.dll';
type
//See MSDN documentation on the TIME_OF_DAY_INFO structure.
PTime_Of_Day_Info = ^TTime_Of_Day_Info;
TTime_Of_Day_Info = record
ElapsedDate : integer;
Milliseconds : integer;
Hours : integer;
Minutes : integer;
Seconds : integer;
HundredthsOfSeconds : integer;
TimeZone : LongInt;
TimeInterval : integer;
Day : integer;
Month : integer;
Year : integer;
DayOfWeek : integer;
end;
constructor TTimeHandler.Create(servername: widestring);
begin
inherited Create;
FServerName := servername;
end;
function TTimeHandler.RemoteSystemTime: TDateTime;
var
Buffer : pointer;
Rek : PTime_Of_Day_Info;
DateOnly, TimeOnly : TDateTime;
timezone : integer;
begin
//if the call is successful...
if 0 = NetRemoteTOD(PWideChar(FServerName),Buffer) then begin
//store the time of day info in our special buffer structure
Rek := PTime_Of_Day_Info(Buffer);
//windows time is in GMT, so we adjust for our current time zone
if Rek.TimeZone <> -1 then
timezone := Rek.TimeZone div 60
else
timezone := 0;
//decode the date from integers into TDateTimes
//assume zero milliseconds
try
DateOnly := EncodeDate(Rek.Year,Rek.Month,Rek.Day);
TimeOnly := EncodeTime(Rek.Hours,Rek.Minutes,Rek.Seconds,0);
except on e : exception do
raise Exception.Create(
'Date retrieved from server, but it was invalid!' +
#13#10 +
e.Message
);
end;
//translate the time into a TDateTime
//apply any time zone adjustment and return the result
Result := DateOnly + TimeOnly - (timezone / 24);
end //if call was successful
else begin
raise Exception.Create('Time retrieval failed from "'+FServerName+'"');
end;
//free the data structure we created
NetApiBufferFree(Buffer);
end;
procedure TTimeHandler.SetLocalSystemTime(settotime: TDateTime);
var
SystemTime : TSystemTime;
begin
DateTimeToSystemTime(settotime,SystemTime);
SetLocalTime(SystemTime);
//tell windows that the time changed
PostMessage(HWND_BROADCAST,WM_TIMECHANGE,0,0);
end;
end.
I believe Windows Time Service only implements SNTP, which is a simplified version of NTP. A full NTP implementation takes into account the stability of your clock in deciding how often to sync.
You can get the full NTP server for Windows here.