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Discussion Groups | AT91SAM ARM | AT91SAM7S USB device force host disconnect
For users of the Atmel AT91SAM7 and AT91SAM9 ARM CPU chips. Atmel has taken a new direction by combining on chip flash and ram with the ARM CPU on a single die. This provides low cost devices for small systems using the ARM CPU. This group is to exchange information to help users get started and learn how to use the devices.
AT91SAM7S USB device force host disconnect - Edward - Mar 4 2:04:49 2008
Hi,
We currently have DP pin connecting to 1.5K pull-up.
I am wondering if there is any way, without doing hardware change, we
can emulate a unplug then plug sequence that forces Windows re-
enumerate?
I've checked AT91SAM7S datasheet that UDP clock can be disabled. But it
doesn't mimic the unplug-plug sequence. Windows does not consider a
disconnect when UDP is gone.
thanks in advance.
Edward
(You need to be a member of AT91SAM -- send a blank email to AT91SAM-subscribe@yahoogroups.com )
We currently have DP pin connecting to 1.5K pull-up.
I am wondering if there is any way, without doing hardware change, we
can emulate a unplug then plug sequence that forces Windows re-
enumerate?
I've checked AT91SAM7S datasheet that UDP clock can be disabled. But it
doesn't mimic the unplug-plug sequence. Windows does not consider a
disconnect when UDP is gone.
thanks in advance.
Edward
(You need to be a member of AT91SAM -- send a blank email to AT91SAM-subscribe@yahoogroups.com )
Re: AT91SAM7S USB device force host disconnect - Foltos - Mar 4 2:31:09 2008
Hi,
the only safe way to do this is to disable the pull-up resistor. Maybe
you can screw up something and trigger a BUS reset, but that is not the
same as a disconnect. Windows ha two USB reset types inside. A soft
reset is just reset signaling on the bus. It resets communication pipes,
but drivers already loaded remain active. A hard reset will build up the
whole driver tree on top of the device. On the device side you cant see
any difference. So you can not know which reset type you triggered.
And if you get it working you can not make assumptions how it will work
with Linux, Vista, or even after the next update to XP.
Foltos
Edward wrote:
>
> Hi,
>
> We currently have DP pin connecting to 1.5K pull-up.
>
> I am wondering if there is any way, without doing hardware change, we
> can emulate a unplug then plug sequence that forces Windows re-
> enumerate?
>
> I've checked AT91SAM7S datasheet that UDP clock can be disabled. But it
> doesn't mimic the unplug-plug sequence. Windows does not consider a
> disconnect when UDP is gone.
>
> thanks in advance.
>
> Edward
>
>
(You need to be a member of AT91SAM -- send a blank email to AT91SAM-subscribe@yahoogroups.com )
the only safe way to do this is to disable the pull-up resistor. Maybe
you can screw up something and trigger a BUS reset, but that is not the
same as a disconnect. Windows ha two USB reset types inside. A soft
reset is just reset signaling on the bus. It resets communication pipes,
but drivers already loaded remain active. A hard reset will build up the
whole driver tree on top of the device. On the device side you cant see
any difference. So you can not know which reset type you triggered.
And if you get it working you can not make assumptions how it will work
with Linux, Vista, or even after the next update to XP.
Foltos
Edward wrote:
>
> Hi,
>
> We currently have DP pin connecting to 1.5K pull-up.
>
> I am wondering if there is any way, without doing hardware change, we
> can emulate a unplug then plug sequence that forces Windows re-
> enumerate?
>
> I've checked AT91SAM7S datasheet that UDP clock can be disabled. But it
> doesn't mimic the unplug-plug sequence. Windows does not consider a
> disconnect when UDP is gone.
>
> thanks in advance.
>
> Edward
>
>
(You need to be a member of AT91SAM -- send a blank email to AT91SAM-subscribe@yahoogroups.com )