[coreboot] USB debug cables and emulation

Joseph Smith joe at settoplinux.org
Thu Jul 3 21:42:05 CEST 2008

> -----Original Message-----
> From: coreboot-bounces at coreboot.org [mailto:coreboot-bounces at coreboot.org]
> On Behalf Of Peter Stuge
> Sent: Thursday, July 03, 2008 1:19 PM
> To: coreboot at coreboot.org
> Subject: Re: [coreboot] USB debug cables and emulation
> On Thu, Jul 03, 2008 at 08:45:15AM -0400, Joseph Smith wrote:
> > I'm thinking a Serial->USB debugger is the way to go
> Ok. Keep in mind that the serial port will probably not be able to
> handle full speed data from the debugged target. I'm not sure what
> the transfer overhead is, but I expect the debug device to be able
> to shuffle quite a bit of data even though each transfer is only 8
> bytes max.
> > to keep the costs down
> As Tom pointed out, this is not a good argument. Serial will only be
> simpler to implement, not lower cost to any degree that matters.
> > Any suggestions, questions, comments?
> You might want to look into the speed thing. I believe the best way
> to do so is to run tests on the NET20DC.
> On Thu, Jul 03, 2008 at 12:28:47PM -0400, Joseph Smith wrote:
> > $20 Dollars for a PCB??? I am going to use a generic PCB you can
> > pick up at radio shack for 2 dollars.
> That will not work. There are no standalone USB 2 high-speed
> function controllers that are usable with those PCBs. You will
> have to design a PCB, or buy a devkit.
> > This is more for educational, learning, and teaching purposes.
> > Everything is not about money you know (or not) :-(
> Manufacturing electronics is VERY expensive, and I think the concern
> is that you will either be spending ridiculous $$ or be forced to
> shut down the project before finish, and that either would be a high
> price for whatever knowledge has been gained.
> USB Debug Devices aren't the best target for learning USB in general
> because the devices need to do some tricks here and there, and thus
> require high end function controllers that can perform.

So everyone is just telling me I should give up??? 

I wonder how many times OLPC herd that???

Ok then I will just give up and go buy a Net20DC :-(

Joseph Smith

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