- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
I am getting a fitter error caused by a 'get_combs' command in the .sdc file; the get_combs command is part of a create_generated_clock command:
-source [get_combs {blah_blah_blah\
|blah_blah_bla\
|blah_blah_bla\
|blah_blah_bla\
|altera_xcvr_10gkr_a10\
|CHANNEL\
|RX_CLK_MUX_LS.gf_rx_clk_mux_inst\
|reduce_or_0~0~la_mlab/laboutt[6]}]
The create_generated _clock command was automatically generated by Timing Analyzer; the chip built without issues before I added the SDC file. The SDC reference manual I have makes no mention of a 'get_combs' command.
I tied replacing the 'get_combs' with a 'get_pins', which seems to work (fitter is still running) but I don't know what effect that might have on the actual application of timing constraints. Any ideas? thanks.
Link Copied
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
Hi,
You can use either of the following to indicate the source node for the generated clock
- get_keepers
- get_nets
- get_pins
- get_ports
- get_registers
You may refer to https://www.intel.com/content/dam/www/programmable/us/en/pdfs/literature/manual/mnl_sdctmq.pdf Chapter 2 to check the differences.
Thanks.
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
Thanks. I have that document, but as I wrote above it does not mention a 'get_combs' command. And any time Quartus/Timing Analyzer has occasion to write the .sdc file, it puts that 'get_combs' command back in there. Replacing the 'get_combs' instances with 'get_nets' seems to work, but I don't understand why the tool inserts a command which it can't process; it seems to me that this is a bug which needs to be addressed.
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
I don't understand. Something in your design is generating this .sdc file? get_combs is not a valid collection. You say "any time Quartus/Timing Analyzer has occasion to write the .sdc file". Are you saying you're doing a "Write SDC" command in the timing analyzer to generate this or is it getting generated in some other way?
#iwork4intel
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
As you probably know, if you use the TA GUI to create a timing constraint, you can then cue TA to write out the updated .sdc file. When TA writes to the .sdc file, it is overwriting the edits I made to eliminate the offending 'get_combs' command. Then I have to manually edit the .sdc file, or Quartus errors out again when I try to do a build.
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
Hi,
Any updates?
Thanks.
-YY
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
Can you post your original .sdc?
#iwork4intel
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
no
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
Hi,
Can you provide a sample test case to reproduce the error?
Thanks
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
I cannot post my design, so I would have to create something which has the same problem, and right now I don't have the spare time for that task.
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
Hi,
It would be difficult to duplicate the error if we cannot have the test case. Is this happened only for some IP?
Thanks.
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
I can't say what IP (if any) caused it.
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
Hi,
Could you share some simple steps to reproduce the error?
Thanks.
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
Hi,
May I know if you have any updates?
Thanks.

- Subscribe to RSS Feed
- Mark Topic as New
- Mark Topic as Read
- Float this Topic for Current User
- Bookmark
- Subscribe
- Printer Friendly Page