[Discuss OpenCPI] [UK OFFICIAL] Multiple Constraints files for a HdlConfig

From: Walters Dominic A <dawalters_at_mail.dstl.gov.uk>
Date: Mon, 27 Jan 20 14:45:45 +0000

Classification: UK OFFICIAL


Hello again,

Is it possible for a HdlConfig file to specify multiple constraints files to be used?
I have a platform atm that has grown to 4 possible configurations, each requiring a complete Constraints file.
These configs are largely very similar (GPIO and RAM pins and iostandards are identical, clocks are set up the same way) with a section of FMC related iostandard constraints and associated input delays that differ.

Currently my HdlConfig looks like this:

    <hdlconfig constraints="<file-name>">
......
    </hdlconfig>

I tried a comma separated list of constraint files, but that doesn't seem to be supported and I struggled to find the section of ocpigen that parses this.
The way I've gotten around this at the moment is by editing vivado-impl.tcl:

_at_ -52,7 +54,7 @@link_design -mode $mode -part $part
    puts "Loading XDC: $constraints"
- read_xdc $constraints
+ read_xdc -unmanaged $constraints
}

This allows the constraints file to be read as pure .tcl, so the .xdc file itself is then allowed use the whole syntax of .tcl, such as:

Ø read_xdc <second_constraints_file>.xdc

Without this change vivado complains, saying that "read_xdc can't be used in a .xdc file".
Is adding "-unmanaged" here okay?
You turn off managed design flows in vivado-synth.tcl, although I'm not sure if that is related to this -unmanaged flag.

Thanks,
Dominic Walters

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Received on Mon Jan 27 2020 - 14:45:45 CST