Timequest Timescale

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Are timequest timing constraints always in nanseconds? I have trawled through the documents, the help system, the forum and via Gxxgle, finding nothing. If I put "5ns" in an SDC is the ns ignored?

Cheers,

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excerpt from altera doc:

"Enter time values in default time units of nanoseconds (ns) with up to three decimal

places. Note that the TimeQuest analyzer does not display the default time unit when

it displays time values.

You can specify a different default time unit with the set_time_format -unit <default

time unit> command, or specify another unit when you enter a time value, for

example, 300ps."

You can also define frequency of clocks as -period "<val> MHz" but this is not standard sdc but unique to TQ

Thanks, Kaz, that's exactly what I wanted to know. Where did you find it?

Regards,

Simon

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Thanks, Kaz, that's exactly what I wanted to know. Where did you find it?

Regards,

Simon

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not easy to find.

qts_qii53019.pdf

topic: switching to quartus timequest timing analyser

timing units, page 8-6

Ah, now I know what to look for, it is also in the SDC and TimeQuest API Reference Manual, although not in the November 2008 version which I printed out long ago.

As an observation, there are a huge number of documents explaining SDC constraints, for an end result of a few sentances of commands at least for the average FPGA. I can't help feeling that the concept is flawed if it is so difficult to use.

Regards,

Simon