Hello,
I have code that puts my device to VLPS when the SLEEP bit is set (due to a suspend) on the USB bus. I'm using the Freescale USB Stack v4.1.1. I monitor USB_USBTRC0_USBRESMEN_MASK to see if I can enter VLPS and then I do.
This works in most cases, but I'm finding on some platforms with some corner cases it does not. I've more or less
proven that I get stuck in the VLPS state instead of asynchronously resuming.
When I get stuck I'm seeing that my Clear Feature Remote Wakeup is getting Stalled as Well.
Is there any known issues with this or known limitations with certain systems?
Is there a suggested approach for power management with the USB stack?
Thanks.
I think the Remote Wakeup is just an indication that the device is not responding (it is still in VLPS).
Can you confirm what the recommended way to put the device in VLPS in regards to USB Suspend is? I think I am missing an asynchronous resume and I get stuck in VLPS.
Update: Looks like it may be a bug with the other interrupts I'm using to come out of VLPS.
Hi Chunks,
Hope it helps.
Have a great day,
Ping
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Hi Chunks,
After had a look through the statement, I'm still a little bit confused with your issue.
So I was wondering if you can clarify the USB remote wakeup event.
I'm looking forward to your reply.
Have a great day,
Ping
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