CE supports a Multimedia timer, though it's not in CF 1.0 or 2.0.  We've rectified that in SDF 2.0 (though your platform must support the Multimedia timer to use it - meaning WM and PPC are out).

So what do high-performance timers buy you?  Well if you look at how a regular timer works, they run at a really low priority and are horrible if you want anything that resembles deterministic behavior.  If you set the interval to say 1000ms, it's guaranteed to not fire in less than 1000ms, but there's actually no upper bound at all.  Jitter of 50ms (5%) would not be exceptional and in fact I've seen substantially worse on systems with a high load.

Our Timer2 class (name is still not finalized, so don't finalize on it) is based on the desktop's Timer class and provides things like a one-shot capability (timer fires once and never again without you having to disable it) and if you derive from it you can have it run a callback instead of raising an event.

Here's a quick example of usage:

void StartMyOneshotTimer
{
  // create a timer
  Timer2 oneShot = new Timer2();

  // make it a one-shot timer
  oneShot.AutoReset = false;

  // fire 3 seconds from enabling
  oneShot.Interval = 3000;

  // allow 10ms latitude for when it fires
  // so it will fire between now + 2995 and now + 3005
  oneShot.Resolution = 10;

  oneShot.Elapsed += new ElapsedEventHandler(oneShot_Elapsed);

  oneShot.Start();
}

void oneShot_Elapsed(object sender, ElapsedEventArgs e)
{
  // do something here
}

You might have noticed that SDF 2.0 no longer has serial or GPS classes.  This is intentional.  CF 2.0 now has serial classes and the Windows Mobile AKU includes GPS support.  We realize that there are some of you out there that are using GPSes on non-WM 5.0 devices and that you'd like to be able to use our stuff under Studio 2005.  For those people, we've spun the Serial and GPS classes into a stand-alone assembly: OpenNETCF.IO.Serial.  There are no plans for an installer for this assembly, and unless we get strong feedback it probably won't make it into the SDF either.

If you're a Windows CE device developer and you've got a device with a persistent registry, you're probably already aware that the CF Registry class doesn't help much for saving the registry, restoring branches from a file or creating volatile keys.  Once again the SDF is here to help with CreateVolatileSubkey, RestoreHiveBasedKey, RestoreRamBasedRegistry, SaveHiveBasedKey and SaveRamBasedRegistry.

One note - the doc says they're in the Registry2 class - that's already been changed to RegistryHelper.

Making apps power aware, especially through the device Power Manager works, but the code is kind of ugly and a pain to implement.  Once again SDF 2.0 simplifies things:

using System;
using System.Windows.Forms;
using OpenNETCF.WindowsCE;

namespace WindowsCETest
{
  public partial class MyPowerAwareClass
  {
    public MyPowerAwareClass()
    {
      DeviceManagement.DeviceWake +=
       new DeviceNotification(DeviceManagement_DeviceWake);

      PowerManagement.PowerUp += new DeviceNotification(PowerManagement_PowerUp);
    }

    void PowerManagement_PowerUp()
    {
      MessageBox.Show("The Power Manager says I'm awake!");
    }

    void DeviceManagement_DeviceWake()
    {
      MessageBox.Show("Device notifications say I'm awake!");
    }
  }
}

The Windows CE operating system supports several notifications for common device events liek changes in AC power, network status changes and time changes.  They are exposed by using the CeRunAppAtEvent or CeSetUserNotification APIs.  While the Windows Mobile Notification Broker provides an interface for some of these, it doesn't provide access to all of them, nor is it available for general Windows CE developers.

SDF 1.4 provided a set of Notification classes that could be used to get these (and those classes are still there in SDF 2.0) but we felt that a simple object model around these would really be a nice thing to have.  So we created the OpenNETCF.WindowsCE.DeviceManagement class.  Now subscribing to the notifications is as simple as this example of detecting when the device time has been modified:

using System;
using System.Windows.Forms;
using OpenNETCF.WindowsCE;

namespace WindowsCETest
{

public class MyClass
{

public MyClass()
{

    DeviceManagement.TimeChanged +=
        new DeviceNotification(DeviceManagement_TimeChanged);
}

void DeviceManagement_TimeChanged()
{
    MessageBox.Show("The time was just changed.");
}

}