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author | Eddie Hung <eddie@fpgeh.com> | 2019-08-23 10:24:59 -0700 |
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committer | Eddie Hung <eddie@fpgeh.com> | 2019-08-23 10:24:59 -0700 |
commit | 4c0404ae024e9595934e738a3e8f52be9c22d090 (patch) | |
tree | 45be3a072228c984358c607d6c60392be8600631 /README.md | |
parent | 4d89c3f468b6090dceabb304b9f56f3a6a597057 (diff) | |
download | yosys-4c0404ae024e9595934e738a3e8f52be9c22d090.tar.gz yosys-4c0404ae024e9595934e738a3e8f52be9c22d090.tar.bz2 yosys-4c0404ae024e9595934e738a3e8f52be9c22d090.zip |
Mention clkbuf_inhibit can be overridden
Diffstat (limited to 'README.md')
-rw-r--r-- | README.md | 15 |
1 files changed, 8 insertions, 7 deletions
@@ -332,17 +332,18 @@ Verilog Attributes and non-standard features that represent module parameters or localparams (when the HDL front-end is run in -pwires mode). -- The ``clkbuf_inhibit`` attribute can be set on a wire to prevent - automatic clock buffer insertion by ``clkbufmap``. - -- The ``clkbuf_sink`` attribute can be set on an input port of a blackbox - module to request clock buffer insertion by the ``clkbufmap`` pass. - - The ``clkbuf_driver`` attribute can be set on an output port of a blackbox module to mark it as a clock buffer output, and thus prevent ``clkbufmap`` from inserting another clock buffer on a net driven by such output. -- The ``iopad_external_pin`` attribute on a blacbox module's port marks +- The ``clkbuf_sink`` attribute can be set on an input port of a module to + request clock buffer insertion by the ``clkbufmap`` pass. + +- The ``clkbuf_inhibit`` is the default attribute to set on a wire to prevent + automatic clock buffer insertion by ``clkbufmap``. This behaviour can be + overridden by providing a custom selection to ``clkbufmap``. + +- The ``iopad_external_pin`` attribute on a blackbox module's port marks it as the external-facing pin of an I/O pad, and prevents ``iopadmap`` from inserting another pad cell on it. |