I am currently working on upgrading my car pc system and need some help related to USB Hubs and USB Devices. My current setup which includes an Intel MacMini and a 4port USB Hub that has been modified to only draw power from my Carnetix 5v regulator (not from the USB port) works great. I am running Vista and have set the computer to sleep when ignition off. When i resume, all of the devices are still connected and do not need to re-initiate.
On my new setup (not installed yet) I am running a D945GCLF2 with a 7port USB Hub modified the same as above. It only draws power from the ac cable connected to a relay that is triggered by the hard drive (the same thing happens on my mac setup above), HOWEVER, this time when I resume from sleep/standby, all my devices connected to the USB hub re-initiate. I can hear them all unplug and replug themselves in (Windows unplug and replug sounds).
NOW, if i choose Hibernate instead of sleep/standby, upon resuming from hibernate all devices work fine even after powering everything down and back up.
On both setups I am disconnecting power to the USB Hub by using a relay attached to the Hard drive power source. This essentially drops power at the same time the hard drive loses power and then regains power at the same instance the hard drive gains power. Both hubs have been modified to cut the 5v lead from the USB but the new 7port hub sometimes still draws some power from the USB (does not do it all the time). I think it could be ground feedback as it is only 2.5v and not the full 5v when fully on. My 4port Hub does not do this. On both setups I am running Centrafuse.
My questions -
Do some USB hubs initiate faster than others?
Is there a major difference between 4port and 7ports Hubs?
For the guys using standby/sleep, is this common and how are you running your setup?
Is there a specific brand of 7port USB Hub that is "better"?
Thanks in advance guys
From my experience, some hubs are complete crap. I went though a couple.
I use Hibernate, so I can't speak to the Sleep/Suspend stuff.
And I'm using just a Molex to power the hub. No relay involved. I think the relay sounds like a potentially unnecessary complication. I would try without the relay.
I am using a carnetix p1900 with 5v attachment. I cannot power my USB Hub from the molex and I am also using a PicoPSU120 for the Mobo and it does not have enough amperage on the 5v to power everything i need.
I am using the relay to kill power the usb hub at the exact same time as the hard drive loses power. It also resumes power to the hub at the exact same time as the hard drive.
My conclusion is that the MacMini deals with USB devices differently than a regular Mobo when going to sleep.
I have decided that I am going to simply use Hibernate instead of sleep. Sure it does take longer to resume but I will eliminate the worry of by battery slowly draining to death and all my devices will not need to be re initiated upon resume.
The new Mobo takes about 40 seconds from the time I press the power button till I hear the music in centrafuse.
I also have remote start so by the time I get to the car it will have already been up and running.
Thanks Crinos and ClockWork for your assistance.