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Re: [Discuss-gnuradio] IPAQ, USRP, and USB 1.1

From: Clark Pope
Subject: Re: [Discuss-gnuradio] IPAQ, USRP, and USB 1.1
Date: Thu, 13 Apr 2006 17:11:34 -0400

From: address@hidden
To: address@hidden
Subject: Re: [Discuss-gnuradio] IPAQ, USRP, and USB 1.1
Date: Thu, 13 Apr 2006 16:12:27 -0400

On Thu, 13 Apr 2006, Lee Patton wrote:
> step 6 may be the hard part as I don't know if the IPAQ has usb2.0. You
> may need a plug in card or you may be happy with usb1.1 and can figure
> out how to modify the usrp firmware to run on 1.1"

The only USB 2 cards I've seen have been CardBus, which is essentially PCI
on a PCMCIA connector - and none of the PDAs I've seen have that,
unfortunately. I'd be happy to be proven wrong, and find a CompactFlash USB
2.0 card, but I would be very surprised if one existed.

> Also Nokia 770 has USB 2.0 connectivity
> http://www.infosyncworld.com/reviews/n/6534.html
> But requires some hacks to get host support
> http://thoughtfix.blogspot.com/2006/01/no-solder-usb-host-method.html

Unfortunately, I believe that the 770 is only a Full Speed (ie: 12Mbps, USB
1.1 speed) device. I know that, out of the box, mine doesn't connect to my
USB 2 Mac at High Speed (480Mbps).

It can be a host, with the power injector design that you've found, so you
can probably get most Linux code to run on it. There's obviously the issue
that there is no hardware FPU, so it's gonna be pretty slow to run most
interesting code.

> Also, as Clark pointed out, the 770 is probably a lot less power
> efficient than the IPAQ.

I'm not sure where that idea comes from, and based on my experience, I
believe that to likely be untrue. The 770's power management is very good -
it implements dyntick very well, letting the CPU sit and run for 7 to 10
days on the standard battery. It sleeps for a couple milliseconds at a time
when it runs through the system idle loop.

The iPaq devices I have used running Linux tend not to have very good power
management at all, often due to less than stellar support of the particular
peripherals on the iPaq in question.

Now, the 770 only has a 220 MHz OMAP processor, so it's not exactly a speed
demon, but it does have a DSP on board, so if you wanted to you could
probably take advantage of that.

Discuss-gnuradio mailing list

I assumed the 770 was a tablet PC, but I see now it's really just an IPAQ of a different name. It appears to burn 500 mA according to the battery life. This is much less than USRP so it shouldn't matter too much. Also, I don't think it would be sleeping in Lee's app so power management may not matter.

The reason I suggested Ipaq is I know there is a very active linux community around it. Here's one with about the same battery as the 770 but it doesn't say how long it runs. It does say usb 2.0 *client*.


The lack of fpu is important but I believe Lee's application is relatively narrowband so even emulated floating point on a 620 MHz processor should handle at least a couple hundred kilohertz. May also be able to just do some of the processing in fixed point by customizing some modules while remaining in the USRP framework.


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