Hi Everyone,
In this post i will be covering the Basics of Floorplanning and how is it done.
Let me start with the question, what is floorplanning? In simple words, Floorplanning is nothing but trying to find good places for the blocks on the floor or chip whatever, so that it minimizes the wirelength and so the delay. It is something like construction plan for a house. When you draw a plan for house you try to place the kitchen, bedroom, rest room, hall and dinning hall according to the area constraints and the rooms which should be close. Similarly in Floorplan, we will try to place the blocks which should be near and others far.
At floorplan level we have two kinds of Macro, called the Hard Macro and the Soft macro. The one which cannot be moved at any point of the ASIC flow are called Hard Macros. These macros come in a fixed position when we get a floorplan file. The one that can have its aspect ratio and connector locations, variable is called Soft Macro. We have standard cells which are generally placed in rows have theirs widths, variable, in the sense these are flexible cells.
Now that we have understood some of the basic terminology, let us try to place these cells or blocks. Let us say i have given a design to a tool and it has brought out the seed (initial floorplan is called seed). There are so many approaches to solve problem of long wire lengths. Basic and most common practice is based on number of interconnects between the cells or blocks. Needless to say, that we have to place the blocks or cells which are highly connected, nearer too each. By doing so we reduce the wirelength required to connect those blocks.
Some times we see a better timing, when we replace a particular cell or block with the existing one. And at times, we see that one particular placement of a soft macro improves the timing rather than keeping it at the place where the tool has suggested us. Once we are done with this we have the final floorplan ready. From here we will proceed with the Power plan.
The resource for all the above definition is from the World's best search engine also called Google. Please search words which you didn't understand in http://www.google.com and know more about them.
Thank You
In this post i will be covering the Basics of Floorplanning and how is it done.
Let me start with the question, what is floorplanning? In simple words, Floorplanning is nothing but trying to find good places for the blocks on the floor or chip whatever, so that it minimizes the wirelength and so the delay. It is something like construction plan for a house. When you draw a plan for house you try to place the kitchen, bedroom, rest room, hall and dinning hall according to the area constraints and the rooms which should be close. Similarly in Floorplan, we will try to place the blocks which should be near and others far.
At floorplan level we have two kinds of Macro, called the Hard Macro and the Soft macro. The one which cannot be moved at any point of the ASIC flow are called Hard Macros. These macros come in a fixed position when we get a floorplan file. The one that can have its aspect ratio and connector locations, variable is called Soft Macro. We have standard cells which are generally placed in rows have theirs widths, variable, in the sense these are flexible cells.
Now that we have understood some of the basic terminology, let us try to place these cells or blocks. Let us say i have given a design to a tool and it has brought out the seed (initial floorplan is called seed). There are so many approaches to solve problem of long wire lengths. Basic and most common practice is based on number of interconnects between the cells or blocks. Needless to say, that we have to place the blocks or cells which are highly connected, nearer too each. By doing so we reduce the wirelength required to connect those blocks.
Some times we see a better timing, when we replace a particular cell or block with the existing one. And at times, we see that one particular placement of a soft macro improves the timing rather than keeping it at the place where the tool has suggested us. Once we are done with this we have the final floorplan ready. From here we will proceed with the Power plan.
The resource for all the above definition is from the World's best search engine also called Google. Please search words which you didn't understand in http://www.google.com and know more about them.
Thank You
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