Sunday, March 31, 2019

ULX3S FPGA Examples

March has been FPGA learning month. I created some examples that were accepted by emard into the  new ULX3S Examples repo.

ULX3S SDR with ALINX AD/DA

Last year, I wrote about the ALINX AD/DA Module that I found on fleabay. Anyone interested in this board should certainly watch the video posted by opentechlab.

Key tidbits of information from the video:

  • DAC is powered by onboard 3.3V regulator.


  • Output from the DAC is differential 3vpp; (true output is difference) each output goes though a low pass filter for anti-aliasing. 


  • Fed into AD 8056 op-amp to convert differential signal to single-ended and level shift from 3vpp to 10vpp (-5 to +5V)


  • Potentiometer is used to control gain of output.


  • There's a bit of input protection on the ADC.


  • Input filter converts 10vpp to 3vpp for ADC chip.


  • MC34063 Step-Up/Down/Inverting Switching Regulators to generate negative rail for output from single +5VDC supply.



Links:

Sunday, February 17, 2019

Notes on ulx3s FPGA: Yosys, Verilog, VHDL, vhdl2vl (Convert VHDL to Verilog)

I want to better understand my new ULX3S, and I was hoping to use FOSS FPGA tools. Here I document some things I've recently learned:

Some key points (from https://gitter.im/ulx3s/Lobby/ ):
  • the standard JTAG programming stuff only programs FPGA SRAM; So rebooting the board will "recover" it 
  • In general you have to go through a fairly tedious process involving Diamond Deployment Tool to create a SVF file to program flash, and this will be very slow Otherwise, you are just programming SRAM (update: this is no longer the case; see ujprog -j flash file.bit
-- @daveshah1
and:
  • I guess the ulx3s-passthru bitstream is by default shipped to you, when you have OLED and ESP32 in box then it makes sense to load the board with passthru.
  • Other boards without OLED and/or ESP32 are probably shipped with f32c with FAT filesystem on config flash to run self-test application at power up.
  • You can erase config flash and ESP32 with whatever you want and flash back to "factory default" from my ulx3s-bin repository.
  • passthru is old source and it needs updated makefile like in prjtrellis-dvi. Yes it tries to find diamond.
  • Passthru is very simple and it could be ported done using opensource tools only. I'm using vhd2vl. For most simple vhdl examples it works great.
  • It can't convert if VHDL source is complex/advanced and has functions and packages.
-- @emard
I case you are wondering about that second USB port (the left one, when facing them):
don't touch the second USB port - it's wired directly into FPGA and thus won't even enumerate on the PC as a serial port unless you do some serious coding at FPGA side (see TinyFPGA Bootloader project - it's pretty much all about it) ... instead, use USB1 which is wired through FT231 chip (see info here)
-- @reostat 
My favorite claims / features:
  • ULX3S is unbrickable
-- @emard
and:
  • There is no realistic chance of irreparable damage to the ULX3S in any case
-- @daveshah1

The term "iCEStorm Toolchain" does not mean Yosys, arache-pnr, nextpnr, Trellis; just iCEStorm.

Yosys, arache-pnr, nextpnr, Trellis supports only Verilog, not VHDL

I have a ULX3S 12K. The Blinky from DoctorWkt expects a 45F chip. Even when editing the original Makefile to instead use the --12 option, nextpnr-ecp5 failed:
Yosys 0.8+148 (git sha1 e112d2fb, clang 6.0.0-1ubuntu2 -fPIC -Os)
Time spent: 54% 11x read_verilog (0 sec), 9% 6x techmap (0 sec), ...
nextpnr-ecp5 --12k --json blinky.json --basecfg ulx3s_empty.config \
--lpf ulx3s_v20.lpf \
--textcfg ulx3s_out.config
unrecognised option '--12k'
Makefile:74: recipe for target 'ulx3s_out.config' failed
make: * [ulx3s_out.config] Error 255
In fact, things were looking pretty bleak, as the nextpnr-ecp5 does not even list the 12F:
nextpnr-ecp5 -- Next Generation Place and Route (git sha1 4c73061)

General options:
  -h [ --help ]             show help
  -v [ --verbose ]          verbose output
  -q [ --quiet ]            quiet mode, only errors and warnings displayed
  -l [ --log ] arg          log file, all log messages are written to this file
                            regardless of -q
  --debug                   debug output
  -f [ --force ]            keep running after errors
  --gui                     start gui
  --run arg                 python file to execute instead of default flow
  --pre-pack arg            python file to run before packing
  --pre-place arg           python file to run before placement
  --pre-route arg           python file to run before routing
  --post-route arg          python file to run after routing
  --json arg                JSON design file to ingest
  --seed arg                seed value for random number generator
  -r [ --randomize-seed ]   randomize seed value for random number generator
  --slack_redist_iter arg   number of iterations between slack redistribution
  --cstrweight arg          placer weighting for relative constraint
                            satisfaction
  --pack-only               pack design only without placement or routing
  --ignore-loops            ignore combinational loops in timing analysis
  -V [ --version ]          show version
  --test                    check architecture database integrity
  --freq arg                set target frequency for design in MHz
  --no-tmdriv               disable timing-driven placement
  --save arg                project file to write
  --load arg                project file to read

Architecture specific options:
  --25k                     set device type to LFE5U-25F
  --45k                     set device type to LFE5U-45F
  --85k                     set device type to LFE5U-85F
  --um-25k                  set device type to LFE5UM-25F
  --um-45k                  set device type to LFE5UM-45F
  --um-85k                  set device type to LFE5UM-85F
  --um5g-25k                set device type to LFE5UM5G-25F
  --um5g-45k                set device type to LFE5UM5G-45F
  --um5g-85k                set device type to LFE5UM5G-85F
  --package arg             select device package (defaults to CABGA381)
  --speed arg               select device speedgrade (6, 7 or 8)
  --basecfg arg             base chip configuration in Trellis text format
                            (deprecated)
  --override-basecfg arg    base chip configuration in Trellis text format
  --textcfg arg             textual configuration in Trellis format to write
  --lpf arg                 LPF pin constraint file(s)
@daveshah1 to the rescue once again!
pass --25k to nextpnr, remove the basecfg if your nextpnr is yesterday or today's build otherwise point it to a 25k basecfg, and then pass --idcode 0x21111043 to ecppack
-- @daveshah1

I'm not sure I would have ever guessed the 25F, and certainly not the --idcode 0x21111043 part. I pulled the latest SymbiFlow/prjtrellis and nextpnr now (git sha1 4c73061), cleaned and rebuilt everything with my new Makefile, and success to build!
[... snip ..]
Info: [ 79471,  79958) |
Info: [ 79958,  80445) |***
Info: [ 80445,  80932) |*
Info: [ 80932,  81419) |***
Info: [ 81419,  81906) |********
337 warnings, 0 errors
ecppack ulx3s_out.config ulx3s.bit --idcode 0x21111043
Now recall I am doing this all in WSL Ubuntu, so there are no native USB devices - thus I am forced to use the Windows version of ujprog to actually upload the code to the ULX3S board.

The amazing thing here - is that Windows applications can be run from within WSL!

This seems to completely circumvent the "No Native USB Devices" in WSL. For example, here's the same app compiled for linux, not finding the JTAG device:



I'm using the very latest FTDI code in my fork of the f32c tools (I created this PR #9). I still encountered some problems with the syntax of the ujprog. I opened issue #10, which was promptly closed - regarding the expected operation. Bottom line is this is the syntax that works:
C:\workspace-git\f32c_tools\ujprog>ujprog ulx3s.bit
ULX2S / ULX3S JTAG programmer v 3.0.92 (built Feb 13 2019 12:27:20)
Using USB cable: ULX3S FPGA 12K v3.0.3
Programming: 100%
Completed in 18.66 seconds.
And I learned a few more things in the close comment:
JTAG doesn't work in COM mode, so no wonder that uploading a bitstream can't work that way, especially not when using the -a modifier, which tells the ujprog to send the file as a stream of bytes.
-- gornjas
From gitter:
ujprog note: supported targets are either -j sram or -j flash
-- @emard
So, ya - I get that all this stuff is obvious to the developers & subject matter experts; However, I struggled to learn each of these things when seeing it all for the first time and relatively little documentation. Although there's no README in the f32c/tools/ujprog, I created one in my fork that hopefully will help others.

As mentioned above: in order to program the ESP32, the FPGA needs to be configured in "Pass-Through" mode. @emard's ulx3s-passthru is written in VHDL.

There's a tool called vhdl2vl that can convert some VHDL to Verilog. Yosys has a VDHL reader plugin based on vhdl2vl.
git clone https://github.com/YosysHQ/yosys-plugins.git
cd yosys-plugins/vhdl
make

# mkdir -p /usr/local/share/yosys/plugins
# cp vhdl.so /usr/local/share/yosys/plugins/vhdl.so
sudo make install
then run yosys, and from the yosys> prompt:
plugin  -i vhdl
plugin  -l
This will add a new read_vhdl command to yosys.

There is more documentation on yosys here.

If the plugin is listed and working, typing read_vhdl in yosys will show help:
1. Executing VHDL frontend.

Syntax error in command `read_vhdl':

    read_vhdl [options] [filename]

Load modules from a VHDL file to the current design.

    -dump_ast1
        dump abstract syntax tree (before simplification)

    -dump_ast2
        dump abstract syntax tree (after simplification)

    -no_dump_ptr
        do not include hex memory addresses in dump (easier to diff dumps)

    -dump_vhdl
        dump ast as VHDL code (after simplification)

    -yydebug
        enable parser debug output

    -nolatches
        usually latches are synthesized into logic loops
        this option prohibits this and sets the output to 'x'
        in what would be the latches hold condition

        this behavior can also be achieved by setting the
        'nolatches' attribute on the respective module or
        always block.

    -nomem2reg
        under certain conditions memories are converted to registers
        early during simplification to ensure correct handling of
        complex corner cases. this option disables this behavior.

        this can also be achieved by setting the 'nomem2reg'
        attribute on the respective module or register.

        This is potentially dangerous. Usually the front-end has good
        reasons for converting an array to a list of registers.
        Prohibiting this step will likely result in incorrect synthesis
        results.

    -mem2reg
        always convert memories to registers. this can also be
        achieved by setting the 'mem2reg' attribute on the respective
        module or register.

    -nomeminit
        do not infer $meminit cells and instead convert initialized
        memories to registers directly in the front-end.

    -ppdump
        dump VHDL code after pre-processor

    -nopp
        do not run the pre-processor

    -nodpi
        disable DPI-C support

    -lib
        only create empty blackbox modules. This implies -DBLACKBOX.

    -noopt
        don't perform basic optimizations (such as const folding) in the
        high-level front-end.

    -icells
        interpret cell types starting with '$' as internal cell types

    -nooverwrite
        ignore re-definitions of modules. (the default behavior is to
        create an error message if the existing module is not a black box
        module, and overwrite the existing module otherwise.)

    -overwrite
        overwrite existing modules with the same name

    -defer
        only read the abstract syntax tree and defer actual compilation
        to a later 'hierarchy' command. Useful in cases where the default
        parameters of modules yield invalid or not synthesizable code.

    -noautowire
        make the default of `default_nettype be "none" instead of "wire".

    -setattr <attribute_name>
        set the specified attribute (to the value 1) on all loaded modules

    -Dname[=definition]
        define the preprocessor symbol 'name' and set its optional value
        'definition'

    -Idir
        add 'dir' to the directories which are used when searching include
        files

The command 'vhdl_defaults' can be used to register default options for
subsequent calls to 'read_vhdl'.

Note that the VHDL frontend does a pretty good job of processing valid
VHDL input, but has not very good error reporting. It generally is
recommended to use a simulator for checking the syntax of the code, rather
than to rely on read_vhdl for that.
The yosys VHDL plugin reads a VDHL file like this:
yosys> read_vhdl ulx3s_v20_passthru_wifi.vhd

3. Executing VHDL frontend.
Parsing VHDL input from `ulx3s_v20_passthru_wifi.vhd' to AST representation.
ERROR: NOT IMPLEMENTED: ulx3s_v20_passthru_wifi.vhd:16 (vhdl_parser.y:1583)
There is probably a different message if it was successful.

There's also the vhd2vl noted on the yosys README.
git clone https://github.com/ldoolitt/vhd2vl.git
cd vhd2vl/src
make
./vhd2vl ../../ulx3s-passthru/rtl/ulx3s_v20_passthru_wifi.vhd
With a bit of help info:
./vhd2vl --help
Usage: vhd2vl [--debug] [--quiet] [--std 1995|2001] source_file.vhd > target_file.v
   or  vhd2vl [--debug] [--quiet] [--std 1995|2001] source_file.vhd target_file.v
That also had limited success:

// File ../../ulx3s-passthru/rtl/ulx3s_v20_passthru_wifi.vhd translated with vhd2vl v3.0 VHDL to Verilog RTL translator
// vhd2vl settings:
//  * Verilog Module Declaration Style: 2001

// vhd2vl is Free (libre) Software:
//   Copyright (C) 2001 Vincenzo Liguori - Ocean Logic Pty Ltd
//     http://www.ocean-logic.com
//   Modifications Copyright (C) 2006 Mark Gonzales - PMC Sierra Inc
//   Modifications (C) 2010 Shankar Giri
//   Modifications Copyright (C) 2002-2017 Larry Doolittle
//     http://doolittle.icarus.com/~larry/vhd2vl/
//   Modifications (C) 2017 Rodrigo A. Melo
//
//   vhd2vl comes with ABSOLUTELY NO WARRANTY.  Always check the resulting
//   Verilog for correctness, ideally with a formal verification tool.
//
//   You are welcome to redistribute vhd2vl under certain conditions.
//   See the license (GPLv2) file included with the source for details.

// The result of translation follows.  Its copyright status should be
// considered unchanged from the original VHDL.

WARNING (line 70): port default initialization ignored.
WARNING (line 70): port default initialization ignored.
WARNING (line 70): port default initialization ignored.
WARNING (line 70): port default initialization ignored.
WARNING (line 70): port default initialization ignored.
syntax error, unexpected GENERATE at "generate" in line 145.

So the reality is that I probably won't be converting VHDL to Verilog anytime soon. However, writing my own Verilog passthrough app should be an excellent beginner FPGA to write.

Tuesday, February 12, 2019

ULX3S - ujprog on Windows WSL or MingGW

I continue to learn about my latest gizmo that arrived all the way from Croatia - the ULXS3. (see my prior blog)

TL;DR; @emard has precompiled binaries. Otherwise compile your own ujprog using apt-get install mingw-w64. A specific makefile is needed to use the new compiler. The current f32c repo has a very old 32-bit ftd2xx.lib; the updated 64 bit version will typically be needed on modern machines. New drivers are here. The ujprog and OpenOCD for ULX3S cannot be used concurrently (FTDI vs libusbK drivers). See the ujprog README that I created.

I've been trying to use WSL for FPGA development. I'm primarily a Windows developer for the Day Job. I like the Windows tools - particularly Visual Studio and VS Code. I also simply think WSL is really cool. (see also WSL on GitHub)

As a reminder, do not modify WSL filesystem file from Windows! Yes, I've seen some pretty weird things happen when I tested that. But feel free to edit any other files. For instance, the entire C:\ directory is available in WSL as /mnt/c/.

Note that similar to the TinyFPGA setup script, I also created a ULXS3 Setup Script.

One of the problems with WSL is the lack of native USB support (glaring omission, I know). So I wanted to see if the ujprog JTAG programmer could be used from Windows. Not super cool having a disjointed environment. For example, when creating the ujprog in WSL:
git clone https://github.com/f32c/tools.git f32c_tools
cp Makefile.linux Makefile
make
./ujprog -t
I see this result:

$ ./ujprog -t
ULX2S / ULX3S JTAG programmer v 3.0.92 (built Feb 12 2019 10:14:16)
Cannot find JTAG cable.

If compiling ujprog for Windows (yes, I admit I tried to type make at a DOS prompt - lol!), install MinGW (I downloaded mine from here; the downloads link however points here). See the wiki: HOWTO Install the MinGW GCC Compiler Suite.


Press "Continue" and upon completion:


Then the MinGW install manager runs:


I chose these options:


Then click "Installation - Apply Changes"


When finished, there should be an indication that "all changes applied successfully"


From Windows, run:

C:\MinGW\msys\1.0\msys.bat


The MINGW32 home directory (from the Windows perspective) will be: C:\MinGW\msys\1.0\home\{your user name}

Unlike other bash prompts, this one does not seem to map the entire C:\ drive, so I re-cloned the repo to my home/workspace directory in MinGW32:

mkdir workspace
cd workspace
git clone https://github.com/f32c/tools.git f32c_tools

Try to compile the linux make file:

cp Makefile.linux Makefile
make

of course results in failure:

$ make
cc -Wall -D__linux__  -static ujprog.c /usr/lib/`uname -m`-linux-gnu/libftdi.a /usr/lib/`uname -m`-linux-gnu/libusb.a -o ujprog
/bin/sh: cc: command not found
make: *** [ujprog] Error 127

Try to compile the win make file (copy the respective Makefile so the -f is not needed every time):

cp Makefile.win Makefile
make

results in a bunch of warnings repeated about usleep, but more importantly a critical error: 'EOPNOTSUPP' undeclared as shown here:

In file included from ujprog.c:55:
[... snip ...]
c:\mingw\include\unistd.h:100:29: note: declared here
 int __cdecl __MINGW_NOTHROW usleep( useconds_t )__MINGW_ATTRIB_DEPRECATED;
                             ^~~~~~
ujprog.c: In function 'shutdown_usb':
ujprog.c:621:2: warning: 'usleep' is deprecated [-Wdeprecated-declarations]
  ms_sleep(10);
  ^~~~~~~~
In file included from ujprog.c:55:
c:\mingw\include\unistd.h:100:29: note: declared here
 int __cdecl __MINGW_NOTHROW usleep( useconds_t )__MINGW_ATTRIB_DEPRECATED;
                             ^~~~~~
ujprog.c: In function 'exec_svf_tokenized':
ujprog.c:1488:9: error: 'EOPNOTSUPP' undeclared (first use in this function); did you mean 'WSAEOPNOTSUPP'?
   res = EOPNOTSUPP;
         ^~~~~~~~~~
         WSAEOPNOTSUPP
ujprog.c:1488:9: note: each undeclared identifier is reported only once for each function it appears in
ujprog.c: In function 'async_read_block':
ujprog.c:2788:4: warning: 'usleep' is deprecated [-Wdeprecated-declarations]
    ms_sleep(backoff * 4);
    ^~~~~~~~
In file included from ujprog.c:55:
[... snip ...]
I tried making the changes described in nmap/nmap#183 - specifically adding to ujprog.c:

#undef EOPNOTSUPP
#define EOPNOTSUPP      WSAEOPNOTSUPP  /* Operation not supported */

And Voila! Success! ujprog.exe for Windows! I created issue this f32c/tools/#8 and this PR f32c/tools#9 to help others that may encounter this problem.

I'm not sure this PR will be accepted, as the root cause may be:
 probably including a wrong errno.h
When running ujprog.exe (from either MinGW32 bash prompt, or DOS command prompt):

ULX2S / ULX3S JTAG programmer v 3.0.92 (built Feb 10 2019 15:25:08)
Usage: ujprog [option(s)] [bitstream_file]

 Valid options:
  -p PORT       Select USB JTAG / UART PORT (default is 0)
  -P COM        Select COM port (valid only with -t or -a)
  -j TARGET     Select bitstream TARGET as SRAM (default) or FLASH (XP2 only)
  -f ADDR       Start writing to SPI flash at ADDR, optional with -j flash
  -s FILE       Convert bitstream to SVF FILE and exit
  -r            Reload FPGA configuration from internal Flash (XP2 only)
  -t            Enter terminal emulation mode after completing JTAG operations
  -b SPEED      Set baudrate to SPEED (300 to 3000000 bauds)
  -e FILE       Send and execute a f32c (MIPS/RISCV) binary FILE
  -x SPEED      Set binary transfer speed, optional with -e
  -a FILE       Send a raw FILE
  -d            debug (verbose)
  -D DELAY      Delay transmission of each byte by DELAY ms
  -q            Suppress messages

This seemed to be a convoluted solution (hm. as always). So a bit of googling and I found a stackoverflow regarding using MinGW for Ubuntu. Something a little more direct from WSL:
sudo apt-get install mingw-w64
It is however, massive, at nearly 750 MB:
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following additional packages will be installed:
  binutils-mingw-w64-i686 binutils-mingw-w64-x86-64 g++-mingw-w64 g++-mingw-w64-i686 g++-mingw-w64-x86-64
  gcc-mingw-w64 gcc-mingw-w64-base gcc-mingw-w64-i686 gcc-mingw-w64-x86-64 mingw-w64-common mingw-w64-i686-dev
  mingw-w64-x86-64-dev
Suggested packages:
  gcc-7-locales wine wine64
The following NEW packages will be installed:
  binutils-mingw-w64-i686 binutils-mingw-w64-x86-64 g++-mingw-w64 g++-mingw-w64-i686 g++-mingw-w64-x86-64
  gcc-mingw-w64 gcc-mingw-w64-base gcc-mingw-w64-i686 gcc-mingw-w64-x86-64 mingw-w64 mingw-w64-common
  mingw-w64-i686-dev mingw-w64-x86-64-dev
0 upgraded, 13 newly installed, 0 to remove and 1 not upgraded.
Need to get 127 MB of archives.
After this operation, 744 MB of additional disk space will be used.
So after the install, a quick compile resulted in:
gcc.exe -c ujprog.c -o ujprog.o -I.
make: gcc.exe: Command not found
Makefile:29: recipe for target 'ujprog.o' failed
make: *** [ujprog.o] Error 127
Ah yes, of course. The Makefile needs to be adjusted to use the new mingw compiler (I added to my PR, suggesting to include a new Makefile.ming32_64:
# Project: ujprog

CPP  = x86_64-w64-mingw32-gcc
CC   = x86_64-w64-mingw32-gcc
WINDRES = windres.exe
RES  =
OBJ  = ujprog.o $(RES)
LINKOBJ  = ujprog.o $(RES)
LIBS = -s -static -L. -lftd2xx
INCS = -I.
CXXINCS = -I.
BIN  = ujprog.exe
CXXFLAGS = $(CXXINCS) -wAll
CFLAGS = $(INCS)
RM = rm -f

.PHONY: all all-before all-after clean clean-custom

all: all-before ujprog.exe all-after


clean: clean-custom
        ${RM} $(OBJ) $(BIN)

$(BIN): $(OBJ)
        $(CC) $(LINKOBJ) -lftd2xx -o "ujprog.exe" $(LIBS)

ujprog.o: ujprog.c
        $(CC) -c ujprog.c -o ujprog.o $(CFLAGS)

The next problem was the ftd2xx.lib file was meant for Linux not Windows, 32 bit not 64 bit .

$ make
x86_64-w64-mingw32-gcc -c ujprog.c -o ujprog.o -I.
x86_64-w64-mingw32-gcc ujprog.o  -lftd2xx -o "ujprog.exe" -s -static -L. -lftd2xx
/usr/bin/x86_64-w64-mingw32-ld: skipping incompatible ./ftd2xx.lib when searching for -lftd2xx
/usr/bin/x86_64-w64-mingw32-ld: cannot find -lftd2xx
/usr/bin/x86_64-w64-mingw32-ld: skipping incompatible ./ftd2xx.lib when searching for -lftd2xx
/usr/bin/x86_64-w64-mingw32-ld: cannot find -lftd2xx
collect2: error: ld returned 1 exit status
Makefile:26: recipe for target 'ujprog.exe' failed
make: *** [ujprog.exe] Error 1
Searching my entire drive, I found the Windows DLL version in my C:\downloads\FTDI directory. Specifically from the WSL perspective:
cd ~/workspace/f32c_tools/ujprog
cp '/mnt/c/download/FTDI/CDM v2.12.28 WHQL Certified/amd64/ftd2xx.lib' ./ftd2xx.lib
make clean
make
This successfully compiled the Windows exe, leaving the file in the Windows-equivalent of my Ubuntu directory:
C:\Users\gojimmypi\AppData\Local\Packages\CanonicalGroupLimited.UbuntuonWindows_79rhkp1fndgsc\LocalState\rootfs\home\gojimmypi\workspace\f32c_tools\ujprog
Sadly, I received the same error in Windows as I did in WSL:
ULX2S / ULX3S JTAG programmer v 3.0.92 (built Feb 12 2019 17:48:54)
FT_Open() failed
Cannot find JTAG cable.
I later discovered this problem was a Windows device driver conflict. In my prior blog, I got OpenOCD working. It uses the libusbK drivers. However, ujprog.exe uses the FTDI drivers. Changing the Windows drivers back to FTDI allows the freshly compiled app to work from Windows!

Now on to getting more serious by uploading my own FPGA and ESP32 code. I'll need to be super sure I can get back to "as shipped" FPGA image, otherwise I may not be able to program the ESP32 since it is not connected directly to any of the exposed pins, rather only the FPGA (same with the SPI display). Thus a passthru app is needed:
Yes, if ESP32 needs FPGA as bypass logic to OLED. If you need ESP32 to write to OLED while FPGA is running user defined core then those few OLED bypass signals must be copy pasted from passthru source to user's source. It's makes very small LUT usage.
--@emard
More info coming soon!

Resources, Inspiration, Credits, and Other Links:

Saturday, February 9, 2019

ULX3S - Day 1

I first learned about the ULX3S via the Hackaday Article last month. (see also hackster.io) There was an offer for boards at the bottom of the radiona.org ulx3s page, so I promptly contacted them. There was only one 12F board left (I confirmed mine is the latest v3.0.3 version), and without the ESP32 connected. Goran was so kind: he not only soldered on the ESP32, but he also included a sticker, headers, the SPI display, and even an awesome 3D-Printed case! (for those that follow me - you know my ongoing quest to find good enclosures for projects)

My board arrived all the way from Croatia, and just in time for the weekend! Power-on success is always a good start:


One of the first things I noticed is that there are TWO micro-USB ports:

ULX3S Board Diagram, from http://radiona.org/ulx3s/
One of them is used for JTAG, connected to a  FTDI FT231XS chip. The other is "connected directly to FPGA". Despite having reviewed the online documentation prior to board arrival, I admit I was surprised to see the two USB connectors. (Uh-oh; which do I use?? will there be ground-loop problem if I use them both?) The feature list only names the one used for JTAG, but both are of course clearly labeled on the diagram (see above); Interesting how one sees things differently when actually holding the physical item.

There are a bunch of interesting links for the ulx3s here.

I received a suggestion that I should first test board with this repo: github.com/emard/ulx3s-bin

There's some information on using JTAG with the ULX3S here: github.com/emard/ulx3s-bin.

My board came with what appeared to be a preloaded WiFi AP (source code should be this one). Goran also suggested that:
for using web interface you will need passthru sample; with ujprog you will program this file and you use -j FLASH option:
ujprog -j FLASH passthru_ulx3s_v20_12k.bit
then power off board. Power on with SD card with config file and it will connect to your network then you can use web interface to upload sram.svf files to SD card and program then from WEB interface or use buttons and OLED.

(I didn't actually do this yet)

To use the WiFi AP, a file called ulx3s-wifi.conf should be placed on a fat32 formated SD card:
{
  "host_name": "ULX3S",
  "ssid": "MyMagicSSID",
  "password": "WiFiPassWord8675309",
  "http_username": "user",
  "http_password": "pass"
}

I installed an 8GB SD card that I had used for a Raspberry Pi (I left all the RPi files) - but it did not seem to be used when I connected to the ESP32 AP. I was unable to connect with Windows 10. It seemed to see there was a "problem" in that there was no internet connectivity (duh). I had more success with my phone, connecting to the address shown on the SPI display:  http://192.168.1.4.1/  - however I was not prompted for a WiFi password, nor a username / password. I suspect somehow the SD card was not detected / not used.

The tools include a forked version of OpenOCD (oddly, no PR's accepted, no ability to open issues). Heads up that some fetches are from https://repo.or.cz/ (not sure why everything is not hosted on GitHub, this certainly makes PR's a bit less convenient - but no issue if not accepted anyhow). I built mine for some JTAG devices I had on hand, as I was not sure what "auto" meant (install if found? install everything?).
sudo apt-get install make libtool pkg-config autoconf automake texinfo libusb-1.0-0-dev
git clone https://github.com/emard/openocd.git ulx32_OpenOCD
cd ulx32_OpenOCD
./bootstrap 
./configure --prefix=/home/$USER/workspace --enable-ftdi --enable-ft232r --enable-stlink  --enable-usb-blaster --enable-jlink  --enable-buspirate
make
sudo make install
So ok, that didn't initially work for me. I ended up with this "error: libusb-1.x is required for the MPSSE mode of FTDI based devices" message:
...
checking whether to build a release... no
checking whether to build Doxygen as HTML... yes
checking whether to build Doxygen as PDF... no
checking whether to enable verbose JTAG I/O messages... no
checking whether to enable verbose USB I/O messages... no
checking whether to enable verbose USB communication messages... no
checking whether to enable malloc free space logging... no
checking whether to enable ZY1000 minidriver... no
checking whether to enable dummy minidriver... no
checking whether standard drivers can be built... yes
checking for LIBUSB1... no
configure: WARNING: libusb-1.x not found, trying legacy libusb-0.1 as a fallback; consider installing libusb-1.x insteadchecking for LIBUSB0... yes
checking for HIDAPI... no
checking for HIDAPI... no
checking for HIDAPI... no
checking for LIBFTDI... no
checking for LIBFTDI... yes
checking for LIBJAYLINK... no
configure: error: libusb-1.x is required for the MPSSE mode of FTDI based devices
The solution was to install libusb-1.0-0-dev. (added, above to apt-get install; many thanks to daveshah1 for that tip) Afterwards, all was well:

Enabled transports:
 - USB ............................ yes
 - TCP ............................ yes



OpenOCD configuration summary
--------------------------------------------------
MPSSE mode of FTDI based devices        yes
ST-Link JTAG Programmer                 yes
TI ICDI JTAG Programmer                 yes (auto)
Keil ULINK JTAG Programmer              yes (auto)
Altera USB-Blaster II Compatible        yes (auto)
Bitbang mode of FT232R based devices    yes
Versaloon-Link JTAG Programmer          yes (auto)
TI XDS110 Debug Probe                   yes (auto)
OSBDM (JTAG only) Programmer            yes (auto)
eStick/opendous JTAG Programmer         yes (auto)
Andes JTAG Programmer                   yes (auto)
USBProg JTAG Programmer                 yes (auto)
Raisonance RLink JTAG Programmer        yes (auto)
Olimex ARM-JTAG-EW Programmer           yes (auto)
CMSIS-DAP Compliant Debugger            no
Cypress KitProg Programmer              no
Altera USB-Blaster Compatible           yes
ASIX Presto Adapter                     yes (auto)
OpenJTAG Adapter                        yes (auto)
SEGGER J-Link Programmer                yes

Despite the instructions, @emard commented on gitter:
Don't use my openocd, it's obsolete (I should remove). Use latest mainstream OpenOCD, they included my patch 
That fork of OpenOCD was from github.com/ntfreak/openocd

Unfortunately, I was once again reminded that USB devices are not supported on WSL. For instance:
$ lsusb -t
/sys/bus/usb/devices: No such file or directory
Although I was able to get around this with the TinyFPGA that could use either USB or TTY drivers, OpenOCD does not. It uses only USB drivers. So I ended up downloading a pre-built binary for OpenOCD on Windows. That didn't initially work either - as the default drivers that Windows installed were the FTDI ones:


As the error appeared that OpenOCD was looking for the libusb drivers:
GNU MCU Eclipse 64-bit Open On-Chip Debugger 0.10.0+dev-00462-gdd1d90111 (2019-01-18-11:42)
Licensed under GNU GPL v2
For bug reports, read
        http://openocd.org/doc/doxygen/bugs.html
Info : only one transport option; autoselect 'jtag'
FT232R num: TCK = 5 DSR
FT232R num: TMS = 6 DCD
FT232R num: TDI = 7 RI
FT232R num: TDO = 3 CTS
FT232R num: TRST = 2 RTS
FT232R num: SRST = 4 DTR
adapter speed: 1000 kHz
Error: libusb_open() failed with LIBUSB_ERROR_NOT_SUPPORTED
Error: ft232r not found: vid=0403, pid=6015, serial=[any]
Zadig to the rescue once again, forcing a change to the drivers to libusbK:

This worked! OpenOCD found the Lattice FPGA:
GNU MCU Eclipse 64-bit Open On-Chip Debugger 0.10.0+dev-00462-gdd1d90111 (2019-01-18-11:42)
Licensed under GNU GPL v2
For bug reports, read
        http://openocd.org/doc/doxygen/bugs.html
Info : only one transport option; autoselect 'jtag'
FT232R num: TCK = 5 DSR
FT232R num: TMS = 6 DCD
FT232R num: TDI = 7 RI
FT232R num: TDO = 3 CTS
FT232R num: TRST = 2 RTS
FT232R num: SRST = 4 DTR
adapter speed: 1000 kHz
Info : clock speed 1000 kHz
Info : JTAG tap: lfe5u12.tap tap/device found: 0x21111043 (mfg: 0x021 (Lattice Semi.), part: 0x1111, ver: 0x2)
Warn : gdb services need one or more targets defined
   TapName             Enabled  IdCode     Expected   IrLen IrCap IrMask
-- ------------------- -------- ---------- ---------- ----- ----- ------
 0 lfe5u12.tap            Y     0x21111043 0x21111043     8 0x05  0xff
open("bitstream.svf"): No such file or directory
svf svf [-tap device.tap]  [quiet] [nil] [progress] [ignore_error]
xsvf (tapname|'plain') filename ['virt2'] ['quiet']
I ran OpenOCD like this, as decribed in the docs:
openocd.exe --file=ft231x.ocd --file=ecp5-XXf.cfg
with the contents of ft231x.ocd:
interface ft232r
ft232r_vid_pid 0x0403 0x6015
# ULX3S specific GPIO setting
ft232r_tck_num DSR
ft232r_tms_num DCD
ft232r_tdi_num RI
ft232r_tdo_num CTS
# trst/srst are not used but must have different values than above
ft232r_trst_num RTS
ft232r_srst_num DTR
adapter_khz 1000
and ecp5-XXf.cfg:

telnet_port 4444
gdb_port 3333

# JTAG TAPs
jtag newtap lfe5u12 tap -expected-id 0x21111043 -irlen 8 -irmask 0xFF -ircapture 0x5
#jtag newtap lfe5u25 tap -expected-id 0x41111043 -irlen 8 -irmask 0xFF -ircapture 0x5
#jtag newtap lfe5u45 tap -expected-id 0x41112043 -irlen 8 -irmask 0xFF -ircapture 0x5
#jtag newtap lfe5u85 tap -expected-id 0x41113043 -irlen 8 -irmask 0xFF -ircapture 0x5

init
scan_chain
svf -tap lfe5u12.tap -quiet -progress bitstream.svf
shutdown


 Make the ujprog (ULX2S / ULX3S JTAG programmer)
git clone https://github.com/f32c/tools.git f32c_tools
cd f32c_tools/ujprog
cp Makefile.linux Makefile
make

Usage for ujprog programmer:
ULX2S / ULX3S JTAG programmer v 3.0.92 (built Feb  8 2019 15:32:33)
Usage: ujprog [option(s)] [bitstream_file]

 Valid options:
  -p PORT       Select USB JTAG / UART PORT (default is 0)
  -P TTY        Select TTY port (valid only with -t or -a)
  -j TARGET     Select bitstream TARGET as SRAM (default) or FLASH (XP2 only)
  -f ADDR       Start writing to SPI flash at ADDR, optional with -j flash
  -s FILE       Convert bitstream to SVF FILE and exit
  -r            Reload FPGA configuration from internal Flash (XP2 only)
  -t            Enter terminal emulation mode after completing JTAG operations
  -b SPEED      Set baudrate to SPEED (300 to 3000000 bauds)
  -e FILE       Send and execute a f32c (MIPS/RISCV) binary FILE
  -x SPEED      Set binary transfer speed, optional with -e
  -a FILE       Send a raw FILE
  -d            debug (verbose)
  -D DELAY      Delay transmission of each byte by DELAY ms
  -q            Suppress messages

Make the ftx-prog programmer:
git clone https://github.com/richardeoin/ftx-prog.git
cd ftx-prog
make

Usage for ftx-prog:
ftx_prog: version 0.2
Modified for the FT-X series by Richard Meadows

Based upon:
ft232r_prog: version 1.23, by Mark Lord.

Usage:  ftx_prog [ ]..

where  must be any of:
    --help                                  # (show this help text)
    --dump                                  # (dump eeprom settings to stdout)
    --verbose                               # (show debug info and raw eeprom contents)
    --save                       <file>     # (save original eeprom contents to file)
    --restore                    <file>     # (restore initial eeprom contents from file)
    --8bit-strings                        # (byte strings)
    --cbus  [1..7]  [Tristate|RxLED|TxLED|TxRxLED|PWREN|SLEEP|Drive_0|Drive_1|GPIO|TXDEN|CLK24MHz|CLK12MHz|CLK6MHz|BCD_Charger|BCD_Charger#|I2C_TXE|I2C_RXF|VBUS_Sense|BitBang_WR|BitBang_RD|Time_Stamp|Keep_Awake]
    --manufacturer               <string>   # (new USB manufacturer string)
    --product                    <string>   # (new USB product name string)
    --old-serial-number          <string>   # (current serial number of device to be reprogrammed)
    --new-serial-number          <string>   # (new USB serial number string)
    --max-bus-power              <number>   # (max bus current in milli-amperes)
    --suspend-pull-down          [on|off]   # (force I/O pins into logic low state on suspend)
    --load-vcp                   [on|off]   # (controls if the VCP drivers are loaded)
    --remote-wakeup              [on|off]   # (allows the interface to be woken up by something other than USB)
    --ft1248-cpol                [high|low] # (set the clock polarity on the FT1248 interface to active high or active low)
    --ft1248-bord                [msb|lsb]  # (set the bit order on the FT1248 interface to msb first or lsb first)
    --ft1248-flow-control        [on|off]   # (flow control for FT1248 interface)
    --i2c-schmitt                [on|off]   # (schmitt trigger on I2C interface)
    --i2c-slave-address          <number>   # (I2C slave address)
    --i2c-device-id              <number>   # (I2C device ID)
    --rs485-echo-supp            [on|off]   # (enable echo supression on the RS485 bus)
    --old-vid                    <number>   # (current vendor id of device to be reprogrammed, eg. 0x0403)
    --old-pid                    <number>   # (current product id of device to be reprogrammed, eg. 0x6001)
    --new-vid                    <number>   # (new/custom vendor id to be programmed)
    --new-pid                    <number>   # (new/custom product id be programmed)
    --invert  [txd|rxd|rts|cts|dtr|dsr|dcd|ri]
    --self-powered               [on|off]   # (specify if chip is bus-powered or self-powered)
    --ignore-crc-error                      # Ignore CRC errors and continue
    --erase-eeprom                          # Erase the EEPROM and exit

So that's my first day with the ULXS3. Pretty cool so far. Stay tuned for more...

Resources, Inspiration, Credits, and Other Links:

Sunday, February 3, 2019

Reinstalling WSL Ubuntu (prep for TinyFPGA RISC-V toolchain)

In my prior blogs, I wrote about the difficulties I encountered in using WSL for the TinyFPGA Verilog tool chain.

TL;DR - Run wslconfig /u Ubuntu in a DOS command prompt. WSL may need to be manually deleted by uninstalling and removing the CanonicalGroupLimited.Ubuntu{...} directory in %USERPROFILE%\AppData\Local\Packages\. Uninstall the Windows "Apps & Features" Ubuntu app, then visit https://aka.ms/wslstore
and re-install Ubuntu app.

As a reminder, do not modify WSL filesystem file from Windows! Yes, I've seen some pretty weird things happen when I tested that. But feel free to edit any other files. For instance, the entire C:\ directory is available in WSL as /mnt/c/.

As it turns out, the biggest problem was the version of Ubuntu I had. Although I didn't think I had it installed for all that long - it was way outdated. 

The first thing to do: completely wipe out the old Ubuntu. I found some instructions on removing Ubuntu - that included both of these options:

From DOS Prompt:
lxrun /uninstall /full
or also from DOS Prompt:
DEL /S %localappdata%\lxss\
I didn't have the lxrun command, nor a C:\Users\gojimmypi\AppData\Local\lxss directory. I tried DOS command prompt, a powershell prompt, the Windows bash prompt (C:\Windows\system32\bash.exe) and Ubuntu prompt. Indeed according to Microsoft, lxrun is deprecated as of Windows 10 1803 and later. As noted in a prior blog, my Ubuntu was installed in this directory:
C:\Users\gojimmypi\AppData\Local\Packages\CanonicalGroupLimited.UbuntuonWindows_79rhkp1fndgsc\LocalState\rootfs\home\gojimmypi
To help find it, you can run a command like this in your WSL instance:
echo wow > ~/zowie.tag
then from a DOS command-prompt:
C:\Users\gojimmypi>dir zowie.tag /s
 Volume in drive C is Windows
 Volume Serial Number is 9078-2015

 Directory of C:\Users\gojimmypi\AppData\Local\Packages\CanonicalGroupLimited.UbuntuonWindows_79rhkp1fndgsc\LocalState\rootfs\home\gojimmypi

02/03/2019  01:43 PM                 4 zowie.tag
               1 File(s)              4 bytes




So in my case, Ubuntu needed to be removed from

 C:\Users\gojimmypi\AppData\Local\Packages\CanonicalGroupLimited.UbuntuonWindows_79rhkp1fndgsc

I was reluctant to try the brute-force directory deletion  route. In part, I've seen where Windows did not "see" the proper file sizes and permissions. I eventually found the wslconfig command.

del CanonicalGroupLimited.UbuntuonWindows_79rhkp1fndgsc /s /q > null:wslconfig /list
pause
wslconfig /unregister distroname


That didn't go so well:

And it didn't just fail, but corrupted the install:

Sometimes I really wonder why I continue to fuss with the Microsoft environment. :/

So in the end, I ran the brute-force directoy delete like this:
del CanonicalGroupLimited.UbuntuonWindows_79rhkp1fndgsc /s /q > null:
wslconfig /unregister distroname
The /s deletes all subdirectories. The /q is "quiet mode" (don't confirm every directory to delete), and I send output to null: as the RISC-V toolchain is massive, and showing all that on the screen would take forever. That actually didn't work, either - leaving behind a ton of directories. So then I tried:
rmdir CanonicalGroupLimited.UbuntuonWindows_79rhkp1fndgsc /s /q
which also did not work, giving an error: CanonicalGroupLimited.UbuntuonWindows_79rhkp1fndgsc\LOCALS~1\rootfs\lib\recovery-mode - The directory is not empty. So I continued to manually delete directories manually until everything was gone. Running WSL from a DOS command prompt shows that nothing is installed:

So on to installing Ubuntu fresh from the Microsoft Store - Linux on Windows upon launching the Ubuntu, we should be able to confirm we have version 18.04 installed:
Installing, this may take a few minutes...
Please create a default UNIX user account. The username does not need to match your Windows username.
For more information visit: https://aka.ms/wslusers
Enter new UNIX username: gojimmypi
Enter new UNIX password:
Retype new UNIX password:
passwd: password updated successfully
Installation successful!
To run a command as administrator (user "root"), use "sudo ".
See "man sudo_root" for details.

gojimmypi@HOSTNAME:~$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 18.04.1 LTS
Release:        18.04
Codename:       bionic

You may wish to setup a custom bash prompt like mine (or see bashrcgenerator.com).


Finally on to installing the tool chain again. I've created a TinyFPGA install gist:
mkdir -p ~/workspace/
cd ~/workspace/
git clone https://gist.github.com/243fc3a6eead72ae3db8fd32f2567c96.git TinyFPGA_Toolchain
cd TinyFPGA_Toolchain
chmod +x TinyFPGA_Toolchain.sh
sudo ./TinyFPGA_Toolchain.sh

Or if you prefer:
sudo ls # pause if copy/paste password prompt
sudo apt-get update --assume-yes
sudo apt-get upgrade --assume-yes

mkdir -p ~/workspace/

cd ~/workspace/
# install icestorm dependencies
# this next install needs a bit of disk space:
#   0 upgraded, 205 newly installed, 0 to remove and 3 not upgraded.
#   Need to get 130 MB of archives.
#   After this operation, 652 MB of additional disk space will be used.
#
sudo apt-get install build-essential clang bison flex libreadline-dev \
                     gawk tcl-dev libffi-dev git mercurial graphviz   \
                     xdot pkg-config python python3 libftdi-dev  --assume-yes

# tinyFPGA BX
git clone --recursive https://github.com/tinyfpga/TinyFPGA-BX.git
cd ~/workspace/

# icestorm
git clone https://github.com/cliffordwolf/icestorm.git icestorm
cd icestorm
make -j$(nproc)
sudo make install
cd ~/workspace/

# arachne-pnr
git clone https://github.com/cseed/arachne-pnr.git arachne-pnr
cd arachne-pnr
make -j$(nproc)
sudo make install
cd ~/workspace/

# nextpnr
git clone https://github.com/YosysHQ/nextpnr.git
# this next line is about another half gig of files!
#   0 upgraded, 249 newly installed, 0 to remove and 3 not upgraded.
#   Need to get 132 MB of archives.
#   After this operation, 623 MB of additional disk space will be used.
#
sudo apt-get install libboost-all-dev python3-dev qt5-default clang-format

cd nextpnr
cmake -DARCH=ice40 .
make -j$(nproc)
sudo make install
cd ~/workspace/

# yosys
git clone https://github.com/cliffordwolf/yosys.git yosys
cd yosys
make -j$(nproc)
sudo make install
cd ~/workspace/

#RISC-V
git clone https://github.com/cliffordwolf/picorv32.git

sudo mkdir /opt/riscv32i
sudo chown $USER /opt/riscv32i

sudo apt-get install autoconf automake autotools-dev curl libmpc-dev \
        libmpfr-dev libgmp-dev gawk build-essential bison flex texinfo \
    gperf libtool patchutils bc zlib1g-dev git libexpat1-dev  --assume-yes

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Wednesday, January 30, 2019

WSL GUI - Using Cygwin X-Server for Graphical Interface

As noted in my prior blog on nextpnr, WSL does not support graphic apps. Yes, in this case nextpnr is a Qt application that should compile in Windows. However, my entire toolchain is currently in WSL. Besides, I simply wanted to see if I could persuade a GUI app to work in WSL. I had used XMing X-windows in the past (click-bait ads on this softonic site, beware). My prior OpenWRT / Wireshark exercise worked well with XMing. However I could not get XMing to work with the latest version of WSL (Ubuntu 18.04 on Windows) so I tried Cygwin instead.

TL;DR: Install Cygwin/X to Windows, consider copy of .Xauthority and then launch the Cygwin server like this:
C:\cygwin64\bin\run.exe --quote /usr/bin/bash.exe -l -c "cd; exec /usr/bin/startxwin -- -listen tcp -nowgl"
Apparently every Cygwin user must have a corresponding Windows user. The user in WSL is not the Cygwin user.

Details: I selected all and only components related to "xorg":


Don't let the small numbers for download size fool you. I ended up with nearly 4GB in my local C:\cygwin64 - install takes a very long time.

In WSL:
# DOS (default C:\cygwin64\bin\) run.exe call to startxwin calls cygwin bash: "/usr/bin/XWin :0 ..." 
export DISPLAY=:0 # you may wish you put in this your ~/.bashrc
 
# copy the Cygwin/X user file to the WSL current user home directory
cp /mnt/c/cygwin64/home/gojimmypi/.Xauthority   ~/.Xauthority
Note that the username / security context in the DOS Windows may be different depending on the username selected when installing the Ubuntu WSL. When running a GUI app in WSL, remember that security is handled by the app started from the DOS prompt.

xclock can be a simple and useful X-Windows app to test if the XServer is working, and can be found in x11-apps:
sudo apt-get install x11-apps
xclock 
The default XWin Server launch as installed does not work for our WSL exercise:
C:\cygwin64\bin\run.exe --quote /usr/bin/bash.exe -l -c "cd; exec /usr/bin/startxwin"
Note: every time you attempt to launch the Cygwin X-Windows Server from a DOS prompt, you should close all running instances in the task bar before opening another. (mine was in the same pop-up menu on the taskbar where USB devices can be disconnected)

To properly launch a Cygwin X-Server for WSL, from a DOS command prompt, launch cygwin with two extra parameters: -- -listen tcp and -nowgl like this:
C:\cygwin64\bin\run.exe --quote /usr/bin/bash.exe -l -c "cd; exec /usr/bin/startxwin -- -listen tcp -nowgl"
The last two options are rather important. Prior to this exercise, I had never used cygwin, so this did take a bit of time to figure out. I've included some of the errors and solutions. Hopefully this document will help others avoid this frustration.

Without setting export DISPLAY=:0 in WSL, this error appears when trying to run xclock in WSL:
Error: Can't open display:
This is of course the same error when the X-Server is not running. Alternatively for nextpnr, we'd see this error:
QStandardPaths: XDG_RUNTIME_DIR not set, defaulting to '/tmp/runtime-gojimmypi'
qt.qpa.screen: QXcbConnection: Could not connect to display
Could not connect to any X display.
Without launching from DOS command prompt with -listen tcp, I saw this same error, as if the server was not running at all:
QStandardPaths: XDG_RUNTIME_DIR not set, defaulting to '/tmp/runtime-gojimmypi'
qt.qpa.screen: QXcbConnection: Could not connect to display :0
Could not connect to any X display.
Without the -nowgl option, I saw this error:
$ nextpnr-ice40 --gui
QStandardPaths: XDG_RUNTIME_DIR not set, defaulting to '/tmp/runtime-gojimmypi'
No XVisualInfo for format QSurfaceFormat(version 2.0, options QFlags(), depthBufferSize -1, redBufferSize 1, greenBufferSize 1, blueBufferSize 1, alphaBufferSize -1, stencilBufferSize -1, samples 1, swapBehavior QSurfaceFormat::SwapBehavior(SingleBuffer), swapInterval 1, profile  QSurfaceFormat::OpenGLContextProfile(CoreProfile))
Falling back to using screens root_visual.
Could not initialize GLX
Aborted (core dumped)
This error means you need a fresh copy of the .Xauthority from cygwin to WSL:
~$ nextpnr-ice40 --gui
QStandardPaths: XDG_RUNTIME_DIR not set, defaulting to '/tmp/runtime-gojimmypi'
Invalid MIT-MAGIC-COOKIE-1 keyqt.qpa.screen: QXcbConnection: Could not connect to display :0
Could not connect to any X display.


Resources, Inspiration, Credits, and Other Links:

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ULX3S FPGA Examples

March has been FPGA learning month. I created some examples that were accepted by emard into the  new ULX3S Examples repo .