gnupic: DIY USB programmer ?
Subject:
Re: DIY USB programmer ?
From:
David Willmore ####@####.####
Date:
11 Jan 2005 17:31:22 +0000
Message-Id: <200501111731.j0BHVBSl031367@localhost.localdomain>
> On Tue, 2005-01-11 at 20:45, Justin Fielding wrote:
> > USB2 would be even better?
>
> Just a quick "heads up" on this, but I presume the only reason, since
> speed is not a consideration in the operation of a PIC programmer, that
> USB2 is desirable, is that a USB1 device forces the bus to spend
> inordinate periods of *time* passing data at the slower rate and thus
> reduces the overall throughput for USB2 capable devices sharing the bus?
Either put the programmer on it's own port off of the root hub or use a
USB2.0 hub. That way High Speed devices sit on their own bus and the
low speed devices sit on their own separate bus.
A USB2.0 hub contains a device called a TT (transaction translator) which
bridges between the USB2.0 high speed world and the Full and Low speed
devices plugged into that hub.
So, there's really no reason for the programmer to be a USB2.0 High Speed
device.
Cheers,
David
