On 5 May 2008, at 11:54, THORNTON Simon wrote: > Hi, > > Just a thought but you could cut the 5V track connected to pin 1 of > the USB plug > and insert a 5V normally closed (NC) relay between the USB connector > and the cut > track. Drive the relay using one of the GPIO pins with a transistor > across the 5V > power rail of the soekris, make sure you put a diode across the > relay contacts.
Surely s/contacts/coil/ to protect the driver transistor from the back EMF when de-energising the coil? > There are various simple relay driver circuits around that will do > this safely > without damaging the GPIO chip. To reset the USB device you turn on > the relay > for 1 sec (cuts the power) then turn it off, the NC means that the > device will be > powered on unless you energise the relay. > > Rgds, > > Simon > > > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Randall > Nortman > Sent: Sunday, May 04, 2008 22:09 > To: [email protected] > Subject: [Soekris] USB power switching? (net4801/Linux) > > I have a remote system with a USB device that apparently is prone to > locking up such that it needs to be power cycled (or unplugged and > plugged back in). A reboot of the system is not adequate to bring it > back to life, because the device (apparently) retains power during the > reboot. Does the USB controller in the net4801 permit power to the > devices to be switched off under software control? And if so, do the > Linux drivers support this? I fear the answer is no to at least one > of those questions, because lsusb -v shows this under the hub > descriptor: > _______________________________________________ > Soekris-tech mailing list > [email protected] > http://lists.soekris.com/mailman/listinfo/soekris-tech -- Bob Bishop +44 (0)118 940 1243 [EMAIL PROTECTED] fax +44 (0)118 940 1295 _______________________________________________ Soekris-tech mailing list [email protected] http://lists.soekris.com/mailman/listinfo/soekris-tech
