On 06/27/2017 01:15 AM, Steve Tell wrote:
I got a message off-list from someone who had used the pin description in my message and patch to construct an openocd configuration
that worked. But I haven't heard of any success with those digilent boards and urjtag.
-Steve
Hi,
one remark about the schematics behind the 'Digilent style JTAG':
Digilent makes a big fuzz about the logic used to connect the FT2232
to the JTAG pins, the schematics of all Digilent boards feature an
'intentionally left blank' page for this part of the schematics.
The vendor Trenz manufactures very nice FPGA boards and accessories.
They offer for example
TE0790 "Xilinx compatible JTAG adapter"
even as 'open hardware', you find the schematics under
https://shop.trenz-electronic.de/en/TE0790-02-XMOD-FTDI-JTAG-Adapter-Xilinx-compatible
and 'Downloads'.
That leaves open what the Lattice CPLD is doing. Trenz offers a nice carrier
board, which also features a integrated 'Xilinx compatible JTAG adapter' as
TE0703 "Carrier Board for ...."
https://shop.trenz-electronic.de/en/TE0703-05-TE0703-Carrier-board-for-Trenz-Electronic-modules-with-4-x-5-cm-form-factor
and under 'Download' you'll find again schematics and in file
SC-PGM-TE703-05_CCSpecial4x5-01_20150121.zip
the sources of the CPLD.
Taken it all together that documents nicely what Digilent doesn't show.
And this is about as simple and trivial as it can be, so it remains
unclear to me they they don't include it in their schematics.
The only unknown is the content of the configuration EEPROM for the FT2232.
With best regards, Walter
--
Dr. Walter F.J. Müller Mail: w.f.j.muel...@gsi.de
------------------------------------------------------------------------------
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot
_______________________________________________
UrJTAG-development mailing list
UrJTAG-development@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/urjtag-development
