wpiman@aol.com wrote:
> We have a Xilinx Flash (XCF series I believe) that we would like to
> program in circuit from a microcontroller in order to support field
> reconfigurability.  This flash has a JTAG backend.  We were thinking
> about using the GPIO ports on a microcontroller to wiggle the JTAG
> lines and load the new files that way.  Problem is we don't know much
> about the upper protocol involved in JTAG and the documentation seems
> hazy.  Has anyone done something similar?  Does software exist that
> will do this for us?
>
Why bother about a Configurator.
If you connect a std flash or SPI dataflash (AT45) to
a fast enough controller (AT91:-) you will be cheaper off..


> Thanks,
> WP

-- 
Best Regards,
Ulf Samuelsson
ulf@a-t-m-e-l.com
This message is intended to be my own personal view and it
may or may not be shared by my employer Atmel Nordic AB 

Another software package is JDrive from Xilinx. I was able to modify it
to work with my system. JDrive uses the IEEE1532 standard. This allows
the programming algorithm, which is contained in a seperate file, to
change  while not effecting the program data.

We've done something similar.  Xilinx has a utility called "playxsvf"
that can be probably modified to fit your environment.  I changed it
to work with a dedicated h/w shifter used to send the JTAGS
data stream without requiring our host processor to do the
low level bit banging.

Look through the Xilinx app notes and you should be able to
find the zip archive that has the source code you'll need.

Good luck!

John Providenza

We have a Xilinx Flash (XCF series I believe) that we would like to
program in circuit from a microcontroller in order to support field
reconfigurability.  This flash has a JTAG backend.  We were thinking
about using the GPIO ports on a microcontroller to wiggle the JTAG
lines and load the new files that way.  Problem is we don't know much
about the upper protocol involved in JTAG and the documentation seems
hazy.  Has anyone done something similar?  Does software exist that
will do this for us?

Thanks,
WP