Usb 1.1, 2.0, Otg. What's The Diff?

[Kyo]

No, it was powered before (really cheap, there's no regulator, but you can power it). I just made it smaller.

I'll also make a 4x AA battery pack for it, once I get my hands on a plug that fits in there that I am willing to sacrifice, probably next month

I tested it with 4.5V and it worked fine, so 4.8 should do great as well. I'd really hate having to use a regulator as that would require me to use 6 batteries

 

[Grench]

Just a thought...

One port has the communications protocols that we're after...
One port has the voltage that we're after...

Why not build one unit that plugs into both and yields one or more 'normal' USB 2.0/1.1 ports?

Or am I missing something in this?

 

[Tom`]

Just a thought...

One port has the communications protocols that we're after...
One port has the voltage that we're after...

Why not build one unit that plugs into both and yields one or more 'normal' USB 2.0/1.1 ports?

Or am I missing something in this?

The only thing you're missing is that if you're going to be plugging something into your handheld, you might as well just get a small USB 2.0 hub and use that.

Although it might be interesting to have an accessory that creates multiple ports from both the OTG and the main USB port - you might be able to get better speed that way (since USB 2.0 is 480 Mbit/s, each port is presumably capable of that, but multiple devices connected to one port wouldn't be as fast as one connected to each port).

 

[javaJake]

Why not build one unit that plugs into both and yields one or more 'normal' USB 2.0/1.1 ports?

Or am I missing something in this?

You can just use a super-cheap, easy-to-find adapter on the OTG port to get yourself the "normal" port you want.

 

[Grench]

The only thing you're missing is that if you're going to be plugging something into your handheld, you might as well just get a small USB 2.0 hub and use that.

At that point you're tied to a wall wart for the hub. It defeats the purpose of the device. I.e mobility.

You can just use a super-cheap, easy-to-find adapter on the OTG port to get yourself the "normal" port you want.

That is limited to power levels that won't drive anything interesting. 100mA isn't it?


So, what would be wrong with what is essentially a custom Y cable using the power lead from the main USB port and the signal leads from the OTG port to yield a single USB 2.0/1.1 500mA female port that could run anything and remain portable? Or is it not that simple?

 

[pelrun]

Actually, 100mA is sufficient for the vast majority of things you might want to plug into your pandora.

The things that would need more power (like a hard drive, etc) are almost certainly going to be USB2.0 and work directly in the main port.

Note: I mean actual usb devices and not those silly usb-powered decorations

 

[DAP]

The only thing you're missing is that if you're going to be plugging something into your handheld, you might as well just get a small USB 2.0 hub and use that.

At that point you're tied to a wall wart for the hub. It defeats the purpose of the device. I.e mobility.

You can just use a super-cheap, easy-to-find adapter on the OTG port to get yourself the "normal" port you want.

That is limited to power levels that won't drive anything interesting. 100mA isn't it?


So, what would be wrong with what is essentially a custom Y cable using the power lead from the main USB port and the signal leads from the OTG port to yield a single USB 2.0/1.1 500mA female port that could run anything and remain portable? Or is it not that simple?


It is not that simple. USB devices negotiate with the master for how much power they can draw. If they ask for too much, the master shuts them down. The OTG port only knows about the 100 mA that it has, it won't know that you bypassed its supply and gave the device a 500 mA source. So when the device asks for 500 mA, the master will shut it down even though you connected the alternate 500 mA source.

 

[Prometheus]

Note: I mean actual usb devices and not those silly usb-powered decorations

But I want a USB Disco Ball and USB Dancing Robot to work with my Pandora at the same time!





:lol:

 

[pelrun]

It is not that simple. USB devices negotiate with the master for how much power they can draw. If they ask for too much, the master shuts them down. The OTG port only knows about the 100 mA that it has, it won't know that you bypassed its supply and gave the device a 500 mA source. So when the device asks for 500 mA, the master will shut it down even though you connected the alternate 500 mA source.

That restriction isn't necessarily fixed - the kernel will not autoconfigure a device which has been plugged in to a port that doesn't support it's request for power, but it can be forced on using udev. Of course, you want to make sure there is sufficient alternate power available before doing that.

However, you'll probably be surprised at just how many things will work directly in the main port, and there are plenty of cheap and tiny unpowered hubs which will get those less cooperative devices going without too much inconvenience.