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Gated clocks are used under some constraints .. usually circuits used for that are technology dependant and can be infered during synthesis if your RTL was originally coded in a specific style/way in order to do that ..
hello all in the multi-clock synchronous design synthesis, there will be virtual clocks for IO port constraints ,when we use it ? can anyone expand more? regards drizzle
synthesis is a process of GIGO. You can think it may be Good Input Good Output ot Garbage In Garbage Out. Syntheis is mainly dependent on design constraints. The validity of synthesis is 100% validity of design constraints. QOR report is the initial phase of analysis. FV report cant guarentee 100% transformation. (...)
for rapid timing closure, U can take bottom-up flow. synthesis the sub-module firstly, then in top-level, set_dont_touch for the pre-synthesis module, and run synthesis. It need more work for interface constraints.
you write what is called RTL code in an HDL putting in mind certain rules and guides to follow in order to have good results in synthesis (meaning not having inferred elements)... then the synthesizer converts the HDL code to gate level netlist :) but u have to give the synthesizer (along with the HDL code), the different constraints for your d
It is done by the synthesis/place and route tool.. in order to meet the timing constraints.. mainly the idea behind doing it is to reduce the routing length... and if the fan out is too high then to reduce it...
See the "PERIOD" item in your ISE "constraints Guide". It shows several ways to apply the constraint to your project. Banjo demonstrated the UCF method. Here's a simple Verilog counter project with a clock PERIOD constraint that's recognized by XST. module top (clk, count); input clk; // synthesis attribute PERIOD clk "50
There are two main things to observe which are the device utilization (how much resources your design is using) and the timing. synthesis report gives an estimate, other steps like (place and route) give more accurate numbers. You should keep adjusting your design till you reach your design constraints requirements. I suggest you dive deep in the X
In general, it is better to give tighter restrictrictions to the tool than you really need. It helps make the synthesis tool more pro-active in terms of meeting timing constraints and also gives you a sort of engineering margin (if your freq. is 62.5 MHz, you dont need a design that cannot run at 62.6 MHZ!!). However, 60MHz+ is a pretty hig
The current synthesis tool can not estimate post-layout long wire delay very well for submicron technologies. set_max_transition: smaller number can force synthesis tool to add more buffers to minimized the RC delay for the heavy loaded singal. set_clock_uncertainty: bigger number can increase the setup time margin to help to overcome the diff
the .db file is for synthesis by DC, Physical Compiler (PC) uses .pdb instead of .db
Generally buffering of nets in layout is refered to as high-fanout-net synthesis rather than CTS. The answer to your question is: remove the two constraints AFTER high-fanout-net synthesis
Hi, Gate Level Simulations gives violations on any signals which are affected due to synthesis. For example, due to some delays statemachines in RTL may go into X state. From such signals identified from Gatelevel netlist, we need to identify, whether it is due to synthesis constraints or due to bugs in RTL design. Regards, ramana
STA comes after you have done logic synthesis and also after place&route. You can use STA when you have a gate-level netlist. Use STA to check for setup, hold and pulse width. Basically use it to check if your design meets its timing constraints.
Yes Surely you can do that . In mentor tool for RTL precison tool you can go block by block and do synthesis and find the edif file. People often do that as there might be the case when each module might hve different contraints for the design. vipul
UCF are used in synthesis as well as in implementation when we r talking abt the FPGA implementation. It consist of all the pin location info, path timing info and other stuff like intilization or ROM values, any other constarint related to placement etc
because of incorrect statistical WLM at synthesis level so proper hold time info is not accurate for STA engine of synthesis tool.
Assertions are a feature HDL of used by simulator for Functional verification. Normally assertion are aplied on expression or on nets. But After synthesis the net names are modified by the synthesis tools also assertion are ignored by sunthesis tool. so i don't think same assertion can be used after synthesis provided u keep assertions (...)
Depends on the synthesis tool you're using. Synplicity Synplify is very popular and easy to use for targetting FPGAs
is the "after" operation of VHDL synthesisable into a actual hardware design or it was only be used for simulation modeling? let say, if i write: a <= b or c after 20ns; will the synthesised hardware actually update the output after (appx) 20ns after a change in inputs or it will just use the default hardware delay and ignore the "after" operatio