Re: [UrJTAG-dev] current hardware experiences

[Arnim L. <arn...@gm...>]

Hi Steve,

> 2) cable xpc_ext: slow - we know this is the case because the 
> necessary reverse-engineering of the protocol has yet to be done, and
>  we're just bit-banging the thing, AFAIK.  No complaint there.  The
> one thing I would suggest we look into is that the Xilinx tools
> always kick a "frequency" command into their svf's, which used to
> blow the thing up, but now just hangs it.  Short of making a script
> or tweaking a makefile to parse the "freq" lines out of the svf, just
> ignoring freq for the xpc would be preferable, I think.

While working on the segfault for the RUNTEST commands, I found that the
calibration loop was broken. Under certain conditions the calibrated
delay value would underflow and you'd end up delaying for 2^32 x 100000
and even more.
The calibration should now quickly find a solution for frequencies above
200k. Below of that some iterations are still required.
Please let me know if this brings the xpc_ext driver back into the game.

Cheers
Arnim