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Honored Contributorclock setup problems!
hi, how can I solve problems of clock setup?
I set in Quartus this options: 1.Assignments -> settings -> Fitter Settings->Optimize hold Timing ->All Paths 2.Assignments -> settings -> Classic Timing anallyzer->Clock settings -> ( Clock_global fmax 50 Mhz Clock_derived fmax 2.5 Mhz ---based on Clock_global Clock_pll fmaz 150 Mhz ---based on Clock_global ) I have problems of clock setup, one of this is: Slack -0.509 ns fmax 139.37 MHz ( period = 7.175 ns ) From interface_PWM:inst8|pwm:spi|lpm_dff0:b2v_inst3|lpm_ff:lpm_ff_component|dffs[0] To interface_PWM:inst8|pwm:spi|lpm_compare1:b2v_inst4|lpm_compare:lpm_compare_componen From clk t|cmpr_pji:auto_generated|ageb_dffe[0] altpll2:inst13|altpll:altpll_component|_clk0 To clk altpll2:inst13|altpll:altpll_component|_clk0 Required setup relationship 6.666 ns required longest P2p time 2.671 ns Actual Longest p2p Time 3.180 ns Help Me!! Thanks! I must set other options in quartus?3 Replies
Altera_ForumTools -> Advisors -> Timing Optimization Advisors is a good starting place for switches in Quartus to help with timing. I would recommend that for a data path problem, but if you have a clock skew problem, the cause of the clock skew should be addressed first. You may be aware of what it is, determined that it has to be, and evaluated that there is no way to reduce the skew, but if not, I would do that first.
- Altera_Forum
So these problems are solved by modifying the code?
There aren't other settings that can help me in the Quartus ? Thanks - Altera_Forum
Requires setup relationship is 6.666ns, so it's a setup path and optimize hold timing won't help it. The problem is the required longest p2p time is 2.671ns. That usually means you have clock skew on the domain. Break out the path and look at the clcok paths to the source and destination and see why they're different. You're data path is only 3.180ns, so it's fast and easily meets the requirement, it's the clock skew that's hurting you.
