On Tuesday 02 February 2010 04:29:36 David Brownell wrote:
> On Monday 01 February 2010, Xiaofan Chen wrote:
> > I do not think libusb0.dll is the problem. It is said that arm-jtag-ew
> > emulates the J-Link in low level API. It takes quite some for
> > OpenOCD to get J-Link working properly. So I will think the
> > first support is probably done by reverse-engineering and there
> > may be something missing in the process.
Arm-jtag-ew does not emulate J-Link on the USB-level protocol because the 
Jlink protocol license forbids that. Arm-jtag-ew uses its own proprietary 
protocol. The compatibility with JLink is on the Jlink.DLL level.

I would suggest to make sure you have the latest firmware installed into the 
device. Simply download the latest driver from olimex.com and use the included 
tool to upgrade the firmware.

> 
> I kind of thought that Dimitar had an "in" at Olimex ... after
> all, he had pre-release access to the USB-TINY-H adapter too!
> Given the right "in", "reverse engineering" might not be needed.
> 
> Regardless, as original author of that code, I've cc'd him to be
> sure he's aware of this reported problem on MS-Windows (modulo
> problems with too-much-email-to-read-it-all).

Unfortunately I don't have hardware to test right now. I could try to help, 
however, if someone posts USB comm dump, e.g. by the usbmon linux driver. Or 
better yet, a dump from HW USB analyzer.

> > There are different firmware version for the J-link. They even
> > use different endpoints and supported command set are
> > not always the same. Maybe this is the case for Olimex
> > Arm-Jtag-EW as well. In that case, even if the original support
> > is good, it may not be good for yours.
> 
> But the arm-jtag-ew driver isn't the same as the jlink driver...
Correct.
> 
> > The first thing to check is the USB Descriptors. You can
> > post yours. Probably the original author of the patch can
> > compare yours with his.
> >
> > Under Windows, you can use usbview to post the
> > USB descriptors.
> > http://www.ftdichip.com/Resources/Utilities.htm
> 

Please note that there is a known issue with RTCK mode. You can disable it 
altogether (fastest), or try to configure around the arm-jtag-ew HW quirk. You 
just have to take into account that is TDI delayed by 3 cycles by the arm-
jtag-ew output.  A possible workaround is to introduce 3 artificial devices on 
the JTAG chain with 1 bit IR lenght and 1 bit DR bypass registers. The driver 
source has a comment on this issue.

Regards,
Dimitar
_______________________________________________
Openocd-development mailing list
[email protected]
https://lists.berlios.de/mailman/listinfo/openocd-development

Reply via email to