Forum Discussion
Question about Monitor
Hello,
is it possible to synthesize the "monitors" on the altera fpgas'. There are Monitor IPs such as Avalon MM Monitor. Can I synthesize such "Monitors"?117 Replies
- Altera_Forum
Honored Contributor
So, "set_multicycle_path" is not a "timing relaxation tool" and should be only used if the design actually has multicycle setup right?.
And if a Path has two cloks of different frequencies [if this difference is INTEGER multiple then it becomes "multicycle" right?] then i can consider these clocks a asynchronous and i can either set this path is "false path" or " separate those two clocks using "set_clock_group -asynchronous" [each clock will be in different groups] right? Thanks, AA - Altera_Forum
Honored Contributor
No. Never add multicycles to someone else's code(i.e. IP) unless you're certain it was designed to be a multicycle. Most likely it is real and is a real problem.
- Altera_Forum
Honored Contributor
I can get rid of this error by adding "set_multicyle_path" and relax the timing, but is this the right way?
- Altera_Forum
Honored Contributor
Yes. (I'm not sure if it's 100% 1:1, but the principles are the same, and it shoudl be very close)
- Altera_Forum
Honored Contributor
Thanks I will take a look at it. Does this manual hold good for Qsys also?
- Altera_Forum
Honored Contributor
Look at:
http://www.altera.com/literature/hb/nios2/edh_ed51007.pdf You're probably well beyond what can be done in Quartus/TimeQuest. You have a design and with all the options switched it only runs so fast due to lots of logic. You may need to optimize the design. (And note that designs only run fast, so you're requirement may be too high for your design...) - Altera_Forum
Honored Contributor
Hello Dave,
I have a Total Negative Slack of 1646 [reduced from 17000 after adding pipeline stages in Qsys]. I have reached maximum pipeline and cannot go any further. The Latch clock and the Launch clocks are the same. How do I solve this problem without using "set_false_path" [This basically does tells TQA not to analyse that particular path and does not solve the problem right?] I can get rid of this error by adding "set_multicyle_path" and relaxing the timing, but is this the right way? And also I don't get a right estimate of the Fmax unless I use the right timing exceptions right? Addition to Above Post: I have found that the failing path is between within the Nios and there is a huge combinational logic between the input and output. Thanks, Aditya - Altera_Forum
Honored Contributor
Thanks Dave.
- Altera_Forum
Honored Contributor
--- Quote Start --- I used Timing Optimization Advisor[TOA] to tweak my design. The results were not consistent. [some times the teaks seems to work and some times it doesn't. Some times there are variations in the normal cases[with no tweaks] that outperforms the cases with tweaks] --- Quote End --- I do not use these tools. However, a general recommendation would be to only use them when optimizing individual components, not an entire design. You may have a single poorly designed component that is affecting the entire design. Determine if all components need to run at the same clock rate, or whether the design can be arranged to have slower peripherals separated into another part of the design, and then access those components via a clock-crossing bridge. Cheers, Dave - Altera_Forum
Honored Contributor
I looked at my private sent message. I said Zero, but I did send you one message, So I am posting it here again since I was not sure whether you had actually received the message.
My message: I used Timing Optimization Advisor[TOA] to tweak my design. The results were not consistent. [some times the teaks seems to work and some times it doesn't. Some times there are variations in the normal cases[with no tweaks] that outperforms the cases with tweaks] Here are my observations: observation 1: Some of the settings after following the TOA suggestions looked like this: restructure multiplexers: OFF state machine encoding: One Hot smart compilation: ON. In spite of this the Fmax did not exceed one of the cases when I hadn't followed the TOA suggestions. observation 2: The compilation time did not change after switching the "Smart Compilation" option to ON. But in one case it reduced from 12min to 8 min. Are these options reliable? Looks like the randomness that occurs during the compilation is very dominant. Am I doing something wrong? Thanks, AA