Honored Contributor
Honored ContributorThanks you both of you for helping out!
I did not pipelined it yet, in order to investigate how much pipeline I needed although I started to think it was a bad idea! Is there any rule of thumb to use for pipelining? I guess the longer it may take the data path the more pipeline registers I need but I am open to your advice... What I am trying to ask is... How can I anticipate at design time how many pipeline stages I may need? At this time I am realizing it later in the design cycle... Due to the recommendations I will go back to the one clock design. I am also starting to pipelining the address calculator and the fir filter. Johannes, What would be the benefit of running the design at 120Mhz instead of 60Mhz? I understand that this may reduce area using resource sharing... is there anything else? Kaz, Regarding your advice --- Quote Start --- - Identify which paths are failing - Your addressing must be pipelined if it takes long paths. - add fabric registers to your multiplier outputs (apart from dedicated block registers). I find this very useful to shorten routing. - adders should pipelined internally and at outputs. --- Quote End --- - I am doing timing report to check failing paths although sometimes it is not that easy to see where really the problem is. - I will pipeline the addressing engine. It has products, sums and sqrt so I made a mistake not pipelining it. However I hoped to run the design wo/pipeline as the speed was not that high (60Mhz) - I am sorry but how do I add fabric registers? Do you mean to edit the design in chip planner? - Most of the adders are being inferred but I may need to use synthesis attributes to let the tool know to pipeline the adders Regarding the side note, The address engine has a sample and hold circuit that holds the address for 3 cycles. So the effective address rate is also 60Mhz matching the ram data port. I am sorry I did not mention that before. Thanks you much for taking the time to carefully read my post! Thanks both of you again and please let me know of any other thoughts!
