USB Remote wakeup

Started by Sandeeptssmg December 7, 2009
Hi,
 I have a query on USB remote wakeup. While the device performs resume
signalling for ~1-15msec which wakes up the hub and inturn the host. 

What if there are multiple resume signalling's initiated from the device
when the hub/host is already up ?  

Will those consecutive resume signalling be ignored from host ?

Kindly let me know your valuable inputs.

Regards,
Sandeep	   
					
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This message was sent using the comp.arch.embedded web interface on
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On Sun, 06 Dec 2009 23:32:16 -0600, Sandeeptssmg wrote:

> Hi, > I have a query on USB remote wakeup. While the device performs resume > signalling for ~1-15msec which wakes up the hub and inturn the host. > > What if there are multiple resume signalling's initiated from the device > when the hub/host is already up ? > > Will those consecutive resume signalling be ignored from host ?
According to USB 2.0, section 7.1.7.7 Resume: A device with remote wakeup capability may not generate resume signaling unless the bus has been continuously in the Idle state for 5 ms (TWTRSM). This allows the hubs to get into their Suspend state and prepare for propagating resume signaling. The remote wakeup device must hold the resume signaling for at least 1 ms but for no more than 15 ms (TDRSMUP). At the end of this period, the device stops driving the bus (puts its drivers into the high-impedance state and does not drive the bus to the J state). So, multiple resume signaling is not allowed. The resume 'K' signaling from the device may interfere with data coming from the hubs/host, and lead to errors.
On Sun, 06 Dec 2009 23:32:16 -0600, Sandeeptssmg wrote:

> Hi, > I have a query on USB remote wakeup. While the device performs resume > signalling for ~1-15msec which wakes up the hub and inturn the host. > > What if there are multiple resume signalling's initiated from the device > when the hub/host is already up ? > > Will those consecutive resume signalling be ignored from host ?
According to USB 2.0, section 7.1.7.7 Resume: A device with remote wakeup capability may not generate resume signaling unless the bus has been continuously in the Idle state for 5 ms (TWTRSM). This allows the hubs to get into their Suspend state and prepare for propagating resume signaling. The remote wakeup device must hold the resume signaling for at least 1 ms but for no more than 15 ms (TDRSMUP). At the end of this period, the device stops driving the bus (puts its drivers into the high-impedance state and does not drive the bus to the J state). So, multiple resume signaling is not allowed. The resume 'K' signaling from the device may interfere with data coming from the hubs/host, and lead to errors.
Hi,
 I have a query on USB remote wakeup. While the device performs resume
signalling for ~1-15msec which wakes up the hub and inturn the host. 

What if there are multiple resume signalling's initiated from the device
when the hub/host is already up ?  

Will those consecutive resume signalling be ignored from host ?

Kindly let me know your valuable inputs.

Regards,
Sandeep	   
					
---------------------------------------		
This message was sent using the comp.arch.embedded web interface on
http://www.EmbeddedRelated.com