HDL_workflow/symbiflow.mdwn

   1 # Installation instructions for Symbiflow with Xilinx Artix7 100T Board
   2
   3 * <https://symbiflow.github.io/>
   4 * <https://github.com/SymbiFlow>
   5 * <https://bugs.libre-soc.org/show_bug.cgi?id=654>
   6
   7 This is now possible with the automated devscript
   8 <https://git.libre-soc.org/?p=dev-env-setup.git;a=blob;f=symbiflow-install;hb=HEAD>
   9
  10 It is, as always, your responsibility to check the contents of any
  11 script before running it.
  12
  13 -------
  14
  15 # Manual instructions
  16
  17 These are notes taken during the process of developing the above
  18 script.  you **do not** need to go through this manual process unless
  19 you are very paranoid.  warning: it took several days to get right.
  20
  21 ## Setting up new debootstrap and chroot into it
  22
  23 Run the following if you wish to isolate the symbiflow build
  24 from other software (reproducible builds) or use the schroot
  25 auto-preparation script here:
  26 <https://git.libre-soc.org/?p=dev-env-setup.git;a=blob;f=mk-deb-chroot;hb=HEAD>
  27
  28     export MY_CHROOT=/stable-chroot
  29     mkdir $MY_CHROOT
  30     debootstrap buster $MY_CHROOT http://deb.debian.org/debian/
  31     mount -t proc proc $MY_CHROOT/proc
  32     mount -t sysfs sysfs $MY_CHROOT/sys
  33     mount -t devpts devpts $MY_CHROOT/dev/pts/
  34     chroot $MY_CHROOT /bin/bash
  35
  36 ## Add Buster Backports Repo and Update
  37
  38 ""buster backports is needed for cmake""
  39
  40     cat << EOF > /etc/apt/sources.list.d/buster_backports.list
  41     deb http://deb.debian.org/debian buster-backports main
  42     EOF
  43
  44 ""oooo annoying, pin preferences for buster-backports""
  45
  46     cat << EOF > /etc/apt/preferences.d/99buster-backports
  47     Package: *
  48     Pin: release a=buster-backports
  49     Pin-Priority: 900
  50     EOF
  51
  52 ""upgrade to buster-backports""
  53
  54     apt-get update -y
  55     apt-get upgrade -y
  56
  57
  58 ## Download necessary softwares
  59
  60     apt-get install -y libcurl3-gnutls/buster git/buster wget
  61
  62     git clone https://github.com/steveicarus/iverilog.git
  63     git clone https://github.com/YosysHQ/yosys.git
  64     git clone https://github.com/YosysHQ/abc.git
  65     git clone https://github.com/oneapi-src/oneTBB.git
  66     git clone https://github.com/verilog-to-routing/vtr-verilog-to-routing.git
  67     git clone https://github.com/yosyshq/icestorm.git
  68     git clone https://github.com/SymbiFlow/prjxray.git
  69     git clone https://github.com/SymbiFlow/prjxray-db.git
  70     git clone https://github.com/SymbiFlow/yosys-symbiflow-plugins.git
  71     git clone https://github.com/SymbiFlow/symbiflow-examples.git
  72     git clone https://github.com/SymbiFlow/symbiflow-arch-defs.git
  73     git clone https://github.com/QuickLogic-Corp/quicklogic-fasm.git
  74     git clone https://github.com/QuickLogic-Corp/quicklogic-fasm-utils.git
  75     git clone https://github.com/SymbiFlow/python-fpga-interchange.git
  76     git clone https://github.com/capnproto/capnproto.git
  77     git clone https://github.com/capnproto/pycapnp.git
  78
  79     wget http://xmlsoft.org/sources/libxml2-2.9.12.tar.gz
  80     wget http://xmlsoft.org/sources/libxslt-1.1.34.tar.gz
  81
  82 ## Steps to compile Icarus Verilog
  83
  84 ### Necessary software to install
  85
  86     apt-get install -y build-essential autoconf make g++ bison flex gperf \
  87       libreadline6-dev
  88
  89 ### Build Icarus Verilog
  90
  91     cd iverilog
  92     git checkout v11_0
  93     sh autoconf.sh
  94     ./configure --prefix=/usr/local/symbiflow/iverilog
  95     make -j$(nproc)
  96     make check
  97     make install
  98     export PATH=/usr/local/symbiflow/iverilog/bin:$PATH
  99     cd ..
 100
 101 ## Steps to compile Yosys
 102
 103 ### Necessary software to install
 104
 105     apt-get install -y cmake
 106     apt-get install -y python3 clang libreadline-dev gawk tcl-dev \
 107     libffi-dev pkg-config libboost-system-dev libboost-python-dev \
 108     libboost-filesystem-dev zlib1g-dev
 109
 110 ### Build Yosys
 111
 112     cd abc
 113     git checkout 4f5f73d18b137930fb3048c0b385c82fa078db38
 114     cd ../yosys
 115     git checkout f44110c62561b21fa673f44d8e115c3ee70d2900
 116     ln -s ../abc .
 117     make -j $(nproc) PREFIX=/usr/local/symbiflow/yosys
 118     make PREFIX=/usr/local/symbiflow/yosys install
 119     install -d -m 0755 /usr/local/symbiflow/share
 120     ln -s ../yosys/share/yosys /usr/local/symbiflow/share
 121     export PATH=/usr/local/symbiflow/yosys/bin:$PATH
 122     cd ..
 123
 124 ## Steps to compile oneTBB
 125
 126 * Note: TBB is needed for multi-threading VTR-Verilog-to-routing
 127 * If not need multi-threading do not build TBB and VTR with TBB
 128
 129 ### Necessary software to install
 130
 131     apt-get install -y libhwloc-dev
 132
 133 ### Build TBB
 134
 135     cd oneTBB
 136     git checkout v2020.3
 137     make -j$(nproc) tbb tbbmalloc tbbproxy tbbbind
 138     install -d -m 0755 /usr/local/symbiflow/oneTBB/lib
 139     cp -dpr include /usr/local/symbiflow/oneTBB
 140     install -Dm755 build/linux_*/*.so* -t /usr/local/symbiflow/oneTBB/lib
 141     cmake -DINSTALL_DIR=/usr/local/symbiflow/oneTBB/lib/cmake/TBB \
 142       -DTBB_VERSION_FILE=/usr/local/symbiflow/oneTBB/include/tbb/tbb_stddef.h \
 143       -DSYSTEM_NAME=Linux -P cmake/tbb_config_installer.cmake
 144     echo "/usr/local/symbiflow/oneTBB/lib" > /etc/ld.so.conf.d/symbiflow.conf
 145     ldconfig
 146     cd ..
 147
 148 ## Steps to compile vtr-verilog-to-routing
 149
 150 ### Necessary software to install
 151
 152     apt-get install -y libeigen3-dev
 153
 154     # Only if want GUI place and route
 155     #apt-get install libcairo2-dev libfontconfig1-dev libx11-dev libxft-dev \
 156     #libgtk-3-dev
 157
 158 ### Build vtr
 159
 160     cd vtr-verilog-to-routing
 161     git checkout 77a3df829fdf509a76b9d7b941376f3835c2576a
 162     mkdir build; cd build
 163     cmake -DCMAKE_INSTALL_PREFIX=/usr/local/symbiflow/vtr ..
 164     make -j $(nproc)
 165     make install
 166     install -d -m 0755 /usr/local/symbiflow/share/vtr
 167     install -m 0644 ../libs/libvtrcapnproto/gen/rr_graph_uxsdcxx.capnp \
 168       /usr/local/symbiflow/share/vtr
 169     export PATH=/usr/local/symbiflow/vtr/bin:$PATH
 170     cd ../..
 171
 172 ### Build vtr-tbb
 173
 174     cd vtr-verilog-to-routing
 175     git checkout 77a3df829fdf509a76b9d7b941376f3835c2576a
 176     mkdir build-tbb; cd build-tbb
 177     cmake -DCMAKE_INSTALL_PREFIX=/usr/local/symbiflow/vtr-tbb \
 178       -DTBB_INCLUDE_DIR=/usr/local/symbiflow/oneTBB/include \
 179       -DTBB_LIBRARY=/usr/local/symbiflow/oneTBB/lib -DBUILD_TYPE=Release ..
 180     LIBRARY_PATH=/usr/local/symbiflow/oneTBB/lib make -j $(nproc)
 181     LIBRARY_PATH=/usr/local/symbiflow/oneTBB/lib make install
 182     install -d -m 0755 /usr/local/symbiflow/share/vtr
 183     install -m 0644 ../libs/libvtrcapnproto/gen/rr_graph_uxsdcxx.capnp \
 184       /usr/local/symbiflow/share/vtr
 185     # Choose either one of path for vtr-binaries
 186     # This one or above one
 187     #export PATH=/usr/local/symbiflow/vtr-tbb/bin:$PATH
 188     cd ../..
 189
 190 ## Steps to compile libxml2
 191
 192 * Newer version is needed which fixes a integer overflow error and is not
 193   provided by Buster.
 194
 195 ### Necessary software to install
 196
 197     apt-get install -y python3-dev
 198
 199 ### Build libxml2
 200
 201     tar -xf libxml2-2.9.12.tar.gz
 202     cd libxml2-2.9.12
 203     ./configure --prefix=/usr/local/symbiflow/libxml2 --with-history \
 204       --with-python=/usr/bin/python3
 205     make -j $(nproc)
 206     make install
 207     echo "/usr/local/symbiflow/libxml2/lib" >> /etc/ld.so.conf.d/symbiflow.conf
 208     ldconfig
 209     export PATH=/usr/local/symbiflow/libxml2/bin:$PATH
 210     cd ..
 211
 212 ## Steps to compile libxslt
 213
 214 * Needed by python3 lxml
 215
 216 ### Build libxslt
 217
 218     tar -xf libxslt-1.1.34.tar.gz
 219     cd libxslt-1.1.34
 220     sed -i s/3000/5000/ libxslt/transform.c doc/xsltproc.{1,xml}
 221     sed -i -r '/max(Parser)?Depth/d' ./tests/fuzz/fuzz.c
 222     ./configure --prefix=/usr/local/symbiflow/libxslt --disable-static \
 223       --without-python \
 224        PKG_CONFIG_PATH=/usr/local/symbiflow/libxml2/lib/pkgconfig
 225     make -j $(nproc)
 226     make install
 227     echo "/usr/local/symbiflow/libxslt/lib" >> /etc/ld.so.conf.d/symbiflow.conf
 228     ldconfig
 229     export PATH=/usr/local/symbiflow/libxslt/bin:$PATH
 230     cd ..
 231
 232 ## Steps to compile prjxray
 233
 234 ### Necessary software to install
 235
 236 ### Build prjxray
 237
 238     cd prjxray
 239     git checkout f7f06896ad26bb7c94680dc323d4b871eded1f4e
 240     git submodule update --init --recursive
 241     mkdir build; cd build
 242     cmake -DCMAKE_INSTALL_PREFIX=/usr/local/symbiflow ..
 243     make -j$(nproc)
 244     make install
 245     export PATH=/usr/local/symbiflow/bin:$PATH
 246     cd ../..
 247
 248 ## Steps to compile yosys-symbiflow-plugins
 249
 250 ### Necessary software to install
 251
 252 ### Build yosys-symbiflow-plugins
 253
 254     cd yosys-symbiflow-plugins
 255     git checkout b170f1d3575568d87901422f846b700169e299be
 256     sed -i -e 's@-include third_party/make-env/conda.mk@#-include third_party/make-env/conda.mk@' Makefile
 257     make -j$(nproc)
 258     make install
 259     cd ..
 260
 261 ## Steps to compile prjxray-db
 262
 263 ### Install prjxray-db
 264
 265     cd prjxray-db
 266     git archive --format=tar --prefix=prjxray-db/ \
 267       cd41f08a8a4d2a60053750a0fe10623b1e2e35da | \
 268       tar -C /usr/local/symbiflow -xf -
 269
 270     cat > /usr/local/symbiflow/bin/prjxray-config << EOF
 271     #!/bin/bash
 272     echo /usr/local/symbiflow/prjxray-db
 273     EOF
 274
 275     chmod +x /usr/local/symbiflow/bin/prjxray-config
 276     cd ..
 277
 278 ## Steps to compile Icestorm
 279
 280 ### Necessary software to install
 281
 282     apt-get install -y libftdi-dev
 283
 284 ### Build Icestorm
 285
 286     cd icestorm
 287     git checkout 83b8ef947f77723f602b706eac16281e37de278c
 288     make -j $(nproc) PREFIX=/usr/local/symbiflow/icestorm
 289     make PREFIX=/usr/local/symbiflow/icestorm install
 290     export PATH=/usr/local/symbiflow/icestorm/bin:$PATH
 291     cd ..
 292
 293 ## Steps to compile capnproto
 294
 295 ### Necessary software to install
 296
 297     apt-get install -y automake autoconf libtool
 298
 299 ### Build capnproto
 300
 301     cd capnproto
 302     git checkout v0.8.0
 303     cd c++
 304     autoreconf -i
 305     ./configure --prefix=/usr/local/symbiflow/capnproto
 306     make -j $(nproc)
 307     make install
 308     echo "/usr/local/symbiflow/capnproto/lib" >> /etc/ld.so.conf.d/symbiflow.conf
 309     ldconfig
 310     export PATH=/usr/local/symbiflow/capnproto/bin:$PATH
 311     cd ../..
 312
 313 ## Steps to compile pycapnp
 314
 315 ### Necessary software to install
 316
 317     apt-get install -y python3-pip cython3
 318
 319 ### Build pycapnp
 320
 321     cd pycapnp
 322     git checkout v1.0.0b1
 323     pip3 install .
 324     cd ..
 325
 326 ##  Git checkout python-fpga-interchange
 327
 328     cd python-fpga-interchange
 329     git checkout 1959b40e998db987c604c0a75664ccb209df13f7
 330     cd ..
 331
 332 ##  Git checkout quicklogic-fasm-utils
 333
 334     cd quicklogic-fasm-utils
 335     git checkout 3d6a375ddb6b55aaa5a59d99e44a207d4c18709f
 336     cd ..
 337
 338 ##  Git checkout quicklogic-fasm
 339
 340     cd quicklogic-fasm
 341     git checkout ee546ff09b2ee25894db3f419366afaf3c4bfe32
 342     cd ..
 343
 344 ## Steps to compile symbiflow-arch-defs
 345
 346 ## Necessary software to install
 347
 348     apt-get install -y nodejs npm python-pytest openocd flake8 python3-numpy \
 349       python3-intervaltree python3-simplejson python3-intelhex \
 350       python3-importlib-metadata python3-jsonschema python3-packaging \
 351       python3-pyparsing python3-pyrsistent python3-tqdm python3-zipp \
 352       python3-typing-extensions python3-ply
 353
 354     pip3 install textx fasm pyjson5 pyyaml tinyfpgab tinyprog pyjson lxml \
 355       progressbar2 hilbertcurve==1.0.5 python-constraint parameterized \
 356       yapf==0.26.0 python-sat
 357
 358 ### Build symbiflow
 359
 360     cd symbiflow-arch-defs
 361     git checkout c2c0f00960baf538eb31e4c42bf5d09dca87bad7
 362     git submodule init
 363     git submodule update --init --recursive
 364     pip3 install ../python-fpga-interchange
 365     pip3 install -e third_party/prjxray
 366     pip3 install -e third_party/xc-fasm
 367     pip3 install ../quicklogic-fasm-utils
 368     pip3 install ../quicklogic-fasm
 369     pip3 install -e third_party/qlf-fasm
 370     pip3 install -e quicklogic/common/utils/quicklogic-timings-importer
 371     pip3 install -e third_party/vtr-xml-utils
 372     pip3 install -e third_party/python-symbiflow-v2x
 373     pip3 install -e third_party/python-sdf-timing
 374     pip3 install -e third_party/symbiflow-xc-fasm2bels
 375
 376     mkdir -p env/conda/envs
 377     ln -s /usr/local/symbiflow env/conda/envs/symbiflow_arch_def_base
 378
 379     sed -i -e 's@add_subdirectory(litex)@#add_subdirectory(litex)@g' \
 380       -e 's@add_subdirectory(ibex)@#add_subdirectory(ibex)@g' \
 381       xc/xc7/tests/soc/CMakeLists.txt
 382
 383 ### Build symbiflow-arch-defs-xc7-artix7-100t
 384
 385     export VPR_NUM_WORKERS=$(nproc)
 386
 387     mkdir build; cd build
 388     cmake -DUSE_CONDA=FALSE -DPRJXRAY_DB_DIR=/usr/local/symbiflow/prjxray-db \
 389       -DINSTALL_FAMILIES=xc7 -DINSTALL_ARCHS=artix7_100t \
 390       -DINSTALL_DEVICES=xc7a100t -DCMAKE_INSTALL_PREFIX=/usr/local/symbiflow ..
 391     cd xc/xc7/archs/artix7_100t
 392     make install
 393     cd ../..
 394     make PINMAP_INSTALL_arty100t-full_xc7a100t_test_arty100t-full_pinmap.csv
 395     install -d -m 0755 /usr/local/symbiflow/share/symbiflow/arch/xc7a100t_test/xc7a100tcsg324-1
 396     install -m 0644 arty100t-full_pinmap.csv /usr/local/symbiflow/share/symbiflow/arch/xc7a100t_test/xc7a100tcsg324-1/pinmap.csv
 397
 398     # Now you can skip to symbiflow-examples.git for external test
 399
 400     # To do builtin counter test; it should build top.bit as final bitstream
 401     cd tests/counter
 402     make counter_arty100t_bit
 403
 404     # see file counter_arty100t/artix7_100t-xc7a100t-virt-xc7a100t-test/top.bit
 405     # it is the bitstream file and if built then success
 406
 407     cd ../../../../..
 408
 409 ### Build symbiflow-arch-defs-xc7-artix7 (xc7a50t)
 410
 411 "If you do not want this target skip"
 412
 413     export VPR_NUM_WORKERS=$(nproc)
 414
 415     mkdir build_artix7; cd build_artix7
 416     cmake -DUSE_CONDA=FALSE -DPRJXRAY_DB_DIR=/usr/local/symbiflow/prjxray-db \
 417       -DINSTALL_FAMILIES=xc7 -DINSTALL_ARCHS=artix7_100t \
 418       -DINSTALL_DEVICES=xc7a50t \
 419       -DCMAKE_INSTALL_PREFIX=/usr/local/symbiflow ..
 420     cd xc/xc7/archs/artix7
 421     make install
 422     cd ../..
 423     make PINMAP_INSTALL_arty-full_xc7a50t_test_arty-full_pinmap.csv
 424     install -d -m 0755 /usr/local/symbiflow/share/symbiflow/arch/xc7a50t_test/xc7a50tfgg484-1
 425     install -m 0644 arty-full_pinmap.csv /usr/local/symbiflow/share/symbiflow/arch/xc7a50t_test/xc7a50tfgg484-1/pinmap.csv
 426     install -d -m 0755 /usr/local/symbiflow/share/symbiflow/arch/xc7a50t_test/xc7a35tcsg324-1
 427     ln -s ../xc7a50tfgg484-1/pinmap.csv /usr/local/symbiflow/share/symbiflow/arch/xc7a50t_test/xc7a35tcsg324-1
 428
 429     # Now you can skip to symbiflow-examples.git for external test
 430
 431     # To do builtin counter test; it should build top.bit as final bitstream
 432     cd tests/counter
 433     make counter_arty100t_bit
 434
 435     # see file counter_arty/artix7-xc7a50t-arty-swbut-roi-virt-xc7a50t-arty-swbut-test/top.bit
 436     # it is the bitstream file and if built then success
 437
 438     cd ../../../../../..
 439
 440 ## Steps to compile symbiflow-examples
 441
 442 ### Build counter test for arty_100
 443
 444     cd symbiflow-examples
 445     git checkout 07a6353627e0b6083728d1022ce30f9093d4c2de
 446
 447     cd xc7
 448     TARGET="arty_100" make -C counter_test
 449
 450     # Should produce top.bit bitstream
 451     # see file counter_test/build/arty_100/top.bit
 452
 453 ### Build counter test for arty_35
 454
 455     TARGET="arty_35" make -C counter_test
 456
 457     # Should produce top.bit bitstream
 458     # see file counter_test/build/arty_/top.bit
 459
 460 ### Build picosoc demo for arty_100
 461
 462     TARGET="arty_100" make -C picosoc_demo
 463
 464     # Should produce top.bit bitstream
 465     # see file picosoc_demo/build/arty_100/top.bit
 466
 467 ### Build picosoc demo for arty_35
 468
 469     TARGET="arty_35" make -C picosoc_demo
 470
 471     # Should produce top.bit bitstream
 472     # see file picosoc_demo/build/arty_35/top.bit
 473
 474 ### Build Linux Litex Demo for arty_100
 475
 476     TARGET="arty_100" make -C linux_litex_demo
 477
 478     # Should produce top.bit bitstream
 479     # see file linux_litex_demo/build/arty_100/top.bit
 480
 481 ### Build Linux Litex Demo for arty_35
 482
 483     TARGET="arty_35" make -C linux_litex_demo
 484
 485     # Should produce top.bit bitstream
 486     # see file linux_litex_demo/build/arty_35/top.bit
 487
 488     cd ../..
 489
 490 ## Steps to compile symbiflow-examples Litex
 491
 492 ### Get Litex
 493
 494     mkdir litex
 495     cd litex
 496
 497     git clone https://github.com/m-labs/migen
 498     git clone https://github.com/litex-hub/pythondata-software-compiler_rt
 499     git clone https://github.com/enjoy-digital/litex
 500     git clone https://github.com/enjoy-digital/litedram
 501     git clone https://github.com/enjoy-digital/liteeth
 502     git clone https://github.com/enjoy-digital/liteiclink
 503     git clone https://github.com/enjoy-digital/litesdcard
 504     git clone https://github.com/litex-hub/litespi
 505     git clone https://github.com/litex-hub/litex-boards
 506     git clone https://github.com/litex-hub/pythondata-cpu-picorv32
 507     git clone https://github.com/litex-hub/pythondata-cpu-vexriscv
 508     git clone https://github.com/litex-hub/pythondata-software-picolibc.git
 509
 510 ### Build Litex
 511
 512 "Git Commits"
 513
 514     migen=6e3f8e565704b4293174aedfb15b3470d233f528
 515     pythondata-software-compiler_rt=fcb03245613ccf3079cc833a701f13d0beaae09d
 516     litex=db20cb172dc982c5879aa8080ec7aa18de181cc5
 517     litedram=1d5192f572c2eb97bc85eb56667e25dc88d725f1
 518     liteeth=8ecc3ca6d9476dd1a8b32b2b6bf3584cd6dcfc02
 519     liteiclink=3d8ecdbcf9f0260292221ff63b0ad3f5e409a955
 520     litesdcard=4edf05e627a8b5f03e632215accec8ab588737e3
 521     litespi=4cb907881bb75999e4c6bb68e211dd5cfc301de9
 522     litex-boards=9e18d9bc34bafb18839512a55dc66ba62e0d4824
 523     pythondata-cpu-picorv32=2e8be513726fb6ffd960f7e18d24e3a86d895107
 524     pythondata-cpu-vexriscv=c4eca1837ebca20b637a0a61e3a93d9446488459
 525     pythondata-software-picolibc=e27c8a7ef8a8e75b6474823aae338efb1a2ca1a9
 526
 527     for pkg in migen pythondata-software-compiler_rt litex litedram \
 528                liteeth liteiclink litesdcard litespi litex-boards \
 529                pythondata-cpu-picorv32 pythondata-cpu-vexriscv \
 530                pythondata-software-picolibc; do
 531      cd "$pkg"
 532      eval git checkout $`echo $pkg`
 533      pip3 install -e .
 534      cd ..
 535     done
 536
 537 #### Build Litex Demo
 538
 539     cd litex-boards
 540
 541     # Arty 100T Picorv32
 542     ./litex_boards/targets/digilent_arty.py --toolchain=symbiflow \
 543       --cpu-type=picorv32 --sys-clk-freq 80e6 --variant a7-100 \
 544       --output-dir build/picorv32/arty_100 --build --no-compile-software
 545     # see file build/picorv32/arty_100/gateware/digilent_arty.bit
 546     # this is the built bitstream
 547
 548     # Arty 100T VexRiscv
 549
 550     ./litex_boards/targets/digilent_arty.py --toolchain=symbiflow \
 551       --cpu-type=vexriscv --sys-clk-freq 80e6 --variant a7-100 \
 552       --output-dir build/vexriscv/arty_100 --build --no-compile-software
 553     # see file build/vexriscv/arty_100/gateware/digilent_arty.bit
 554     # this is the built bitstream
 555
 556     # Arty 35T Picorv32
 557
 558     ./litex_boards/targets/digilent_arty.py --toolchain=symbiflow \
 559       --cpu-type=picorv32 --sys-clk-freq 80e6 --variant a7-35 \
 560       --output-dir build/picorv32/arty_35 --build --no-compile-software
 561     # see file build/picorv32/arty_35/gateware/digilent_arty.bit
 562     # this is the built bitstream
 563
 564     # Arty 35T VexRiscv
 565
 566     ./litex_boards/targets/digilent_arty.py --toolchain=symbiflow \
 567       --cpu-type=vexriscv --sys-clk-freq 80e6 --variant a7-35 \
 568       --output-dir build/vexriscv/arty_35 --build --no-compile-software
 569     # see file build/vexriscv/arty_35/gateware/digilent_arty.bit
 570     # this is the built bitstream
 571