AppWidget only updates once

I have a problem with an appwidget. It doesn't have a configura开发者_开发百科tion activity. When I set android:updatePeriodMillis="10000" ( know this shouldn't be done but it's just for testing) in the emulator the onUpdate(...) function is called every 10 seconds. But when i install my app on my real phone (motorola milestone) onUpdate(...) is only called when I add the widget to the home screen. And never again. Any ideas why this happens on the real device but not in the emulator?

What Sdk are u using?

since Android sdk 1.6 the widget update minimum period is 30 minutes.