How to trigger the EXTI_Line18 event/USBWakeup IRQ

stephen · ‎2009-12-06

Posted on December 06, 2009 at 12:07

stephen · ‎2011-05-17

Posted on May 17, 2011 at 13:32

I'm trying to put my application into STOP mode and then use the EXTI_Line18 to trigger the USBWakeup IRQ.

Does anyone know what events will cause the EXTI_Line18 to create an interrupt that will then trigger USBWakeup?

I've seen mention that the USB cable being attached will do this, but because I am developing a bus-powered device this would be the same for me as a power off/power on.

Are there are any other events I can use?

My USB device is HID based and I have a test tool that I can use to send/receive commands at the application level.

However, once I enter STOP mode the USB device disappears from my Windows Device Manager (because the USB ISR is not being serviced?)

Any thoughts welcome,

SteveO.

tomas23 · ‎2011-05-17

Posted on May 17, 2011 at 13:32

The USB suspend/resume is described in USB specification and it is used if ie. PC goes to stand-by.

Then PC host stops giving periodic packets, after 3 ms all devices must enter low-power mode (avg. < 0.5 mA). When PC wakes up, it restarts the USB comm. and the devices restart with resume event.