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Altera_Forum
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11 years ago

Fmax Improvment

I'm trying to improve Fmax in our design. See the archived quartus II proejct file in the attachment. The source files are also attached. In my currrent design, after compilation, Fmax can reach ...
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Altera_Forum
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11 years ago

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You can find a lot of examples of pipelines in books and on web. Have you found where to insert pipeline in VHDL?

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I think I should insert pipeline in the code below. Am I right? 

-- Gray bar(16 gray bars)
      	HelperGrayBar <= "1111"; -- gray level 15	
      	if unsigned(Setting_Pixel) < shift_right(unsigned(Setting_TotPixel),4) then
      		HelperGrayBar <= "0000"; -- black
      	elsif unsigned(Setting_Pixel) < shift_right(unsigned(Setting_TotPixel),3) then
      		HelperGrayBar <= "0001"; -- gray level 1
			elsif unsigned(Setting_Pixel) < ((shift_right(unsigned(Setting_TotPixel),3)) + (shift_right(unsigned(Setting_TotPixel),4))) then
      		HelperGrayBar <= "0010"; -- gray level 2
      	elsif unsigned(Setting_Pixel) < shift_right(unsigned(Setting_TotPixel),2) then
      		HelperGrayBar <= "0011"; -- gray level 3
			elsif unsigned(Setting_Pixel) < ((shift_right(unsigned(Setting_TotPixel),2)) + (shift_right(unsigned(Setting_TotPixel),4))) then
      		HelperGrayBar <= "0100"; -- gray level 4
			elsif unsigned(Setting_Pixel) < ((shift_right(unsigned(Setting_TotPixel),2)) + (shift_right(unsigned(Setting_TotPixel),3))) then
      		HelperGrayBar <= "0101"; -- gray level 5
			elsif unsigned(Setting_Pixel) < ((shift_right(unsigned(Setting_TotPixel),1)) - (shift_right(unsigned(Setting_TotPixel),4))) then
      		HelperGrayBar <= "0110"; -- gray level 6
			elsif unsigned(Setting_Pixel) < (shift_right(unsigned(Setting_TotPixel),1)) then
      		HelperGrayBar <= "0111"; -- gray level 7
			elsif unsigned(Setting_Pixel) < ((shift_right(unsigned(Setting_TotPixel),1)) + (shift_right(unsigned(Setting_TotPixel),4))) then
      		HelperGrayBar <= "1000"; -- gray level 8
			elsif unsigned(Setting_Pixel) < ((shift_right(unsigned(Setting_TotPixel),1)) + (shift_right(unsigned(Setting_TotPixel),3))) then
      		HelperGrayBar <= "1001"; -- gray level 9
			elsif unsigned(Setting_Pixel) < ((shift_right(unsigned(Setting_TotPixel),1)) + (shift_right(unsigned(Setting_TotPixel),3)) + (shift_right(unsigned(Setting_TotPixel),4))) then
      		HelperGrayBar <= "1010"; -- gray level 10
			elsif unsigned(Setting_Pixel) < ((shift_right(unsigned(Setting_TotPixel),1)) + (shift_right(unsigned(Setting_TotPixel),2))) then
      		HelperGrayBar <= "1011"; -- gray level 11
			elsif unsigned(Setting_Pixel) < ((shift_right(unsigned(Setting_TotPixel),1)) + (shift_right(unsigned(Setting_TotPixel),2)) + (shift_right(unsigned(Setting_TotPixel),4))) then
      		HelperGrayBar <= "1100"; -- gray level 12
			elsif unsigned(Setting_Pixel) < ((shift_right(unsigned(Setting_TotPixel),1)) + (shift_right(unsigned(Setting_TotPixel),2)) + (shift_right(unsigned(Setting_TotPixel),3))) then
      		HelperGrayBar <= "1101"; -- gray level 13
			elsif unsigned(Setting_Pixel) < (unsigned(Setting_TotPixel) - (shift_right(unsigned(Setting_TotPixel),4))) then
      		HelperGrayBar <= "1110"; -- gray level 14
      	end if;

If there are some limitation of the resources that i'm not allowed to add more pipeline, do you have some ideas to simplify the logic in my design?