gnupic: Re: [gnupic] Follow-up question to the thread about Ben's port of Brad's Lab2 to gpasm
Subject:
Re: [gnupic] Follow-up question to the thread about Ben's port of Brad's Lab2 to gpasm
From:
Nicholas Robinson ####@####.####
Date:
3 Jan 2006 11:12:33 +0000
Message-Id: <200601031114.34306.npr@bottlehall.co.uk>
On Tuesday 03 January 2006 09:01, Wojtek Zabolotny wrote:
> Nicholas Robinson napisał(a):
> >lsusb has never shown anything; occasionally I get some dmesg messages but
> > not every time. I've once had a dmesg report that a high speed device had
> > been connected but usually it's something along the lines of:
> >
> >Jan 2 15:41:30 paulo kernel: usb 2-1: new low speed USB device using
> > uhci_hcd and address 11
> >Jan 2 15:41:30 paulo kernel: usb 2-1: device descriptor read/64, error
> > -71 Jan 2 15:41:30 paulo kernel: usb 2-1: device descriptor read/64,
> > error -71 Jan 2 15:41:30 paulo kernel: usb 2-1: new low speed USB device
> > using uhci_hcd and address 12
> >Jan 2 15:41:30 paulo kernel: usb 2-1: device descriptor read/64, error
> > -71 Jan 2 15:41:30 paulo kernel: usb 2-1: device descriptor read/64,
> > error -71 Jan 2 15:41:31 paulo kernel: usb 2-1: new low speed USB device
> > using uhci_hcd and address 13
> >Jan 2 15:41:31 paulo kernel: usb 2-1: device not accepting address 13,
> > error -71
> >Jan 2 15:41:31 paulo kernel: usb 2-1: new low speed USB device using
> > uhci_hcd and address 14
> >Jan 2 15:41:32 paulo kernel: usb 2-1: device not accepting address 14,
> > error -71
> >
> >when they get to syslog.
> >
> >
> >
> >From my experience with USB firmware I can see that to obtain the above
>
> messages it is enough to provide the proper pull-up. I obtained similar
> results when my firmware was absolutely dead ;-).
Funny you should say that, I got a bit suspicious last night and downloaded a
test programme that just blinks a few leds and it is still okay. I don't know
if it is possible for pics to sulk but my one stopped doing anything very
much for about half an hour!
> If you want to see what's going on on the USB bus, then recompile your
> kernel with debugfs (switch it on in "kernel hacking" section), then
> mount debugfs somewhere (I usually do: "#mkdir /tmp/debug; mount mount
> -t *debugfs* none /tmp/debug"), then insert the "usbmon" module.
> It allows you to monitor the low level USB traffic. More info can be
> found in: "Documentation/usb/usbmon.txt" in your kernel sources and
> here: http://people.redhat.com/zaitcev/linux/OLS05_zaitcev.pdf
> I've found the usbmon to be an essential tool when debugging USB
> firmware without debugging capabilities on my target board...
This sounds a great way forward, I've never used this before so it'll be fun
having a go. Thanks very much for your help. I'll try it tonight.
Nick
