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RTimothyEdwards / open_pdks

PDK installer for open-source EDA tools and toolchains. Distributed with setups for the SkyWater 130nm and Global Foundries 180nm open processes.
http://opencircuitdesign.com/open_pdks
Apache License 2.0
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Put biggest buffer 1st in CTS_CLK_BUFFER_LIST #242

Open maliberty opened 2 years ago

maliberty commented 2 years ago

In sky130/openlane/sky130_fd_sc_hd/config.tcl you have:

set ::env(CTS_CLK_BUFFER_LIST) "sky130_fd_sc_hd__clkbuf_2 sky130_fd_sc_hd__clkbuf_4 sky130_fd_sc_hd__clkbuf_8"

it is currently better to put the largest buffer first like:

set ::env(CTS_CLK_BUFFER_LIST) "sky130_fd_sc_hd__clkbuf_8 sky130_fd_sc_hd__clkbuf_4 sky130_fd_sc_hd__clkbuf_2"

OR will eventually not care but for now this gives better results.

@antonblanchard FYI

maliberty commented 2 years ago

This applies to hs and the other config.tcl too

RTimothyEdwards commented 2 years ago

Thanks, done.