Timequest Timescale

[Altera_Forum]

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,

[Altera_Forum]

--- Quote Start ---  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,  --- Quote End ---    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

[Altera_Forum]

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

Regards, Simon

[Altera_Forum]

--- Quote Start ---  Thanks, Kaz, that's exactly what I wanted to know. Where did you find it? Regards, Simon  --- Quote End ---    not easy to find.  qts_qii53019.pdf topic: switching to quartus timequest timing analyser timing units, page 8-6

[Altera_Forum]

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